Detection of multi-residue insecticides in bitter gourd using Glutathione-S-Transferase enzyme based different analytical techniques

Detection of multi-residue insecticides in bitter gourd using Glutathione-S-Transferase enzyme based different analytical techniques | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Detection of multi-residue insecticides in bitter gourd using Glutathione-S-Transferase enzyme based different analytical techniques M. M. Mawtham, K. Bhuvaneswari, S. Thirumalairajan, A. Suganthi, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4900144/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract The food safety issues related to the pesticide residues in agricultural produce have increased the demand for instruments that can rapidly, sensitively, and selectively detect pesticide residues in food commodities. This idea served as the impetus for the development of protocols for the detection and quantification of various insecticide residues using GST-based biosensor probes. We demonstrated the effectiveness of GST-based biosensor and compared with analytical methods such as GC-MS/LC-MS for application in detection of multi-residue insecticides viz. , synthetic pyrethroid and neonicotinoid in bitter gourd samples. Spectrophotometric analysis was confirmed from Michaelis-Menten constant ( K m ) and maximum velocity ( V max ) in the range 0.00178–0.00767 M and 0.01519–0.05249 mM/s for six different insecticides. Further, GST-based biosensor for the detection of various insecticides showed good linear curve (R 2 > 0.98) in the range from 0.01 to 0.5 mg kg − 1 with LOD and LOQ calculated in 0.01 and 0.05 mg kg − 1 . Method validation parameters namely linearity, recovery inhibition were calculated 1.83–65.10%, accuracy (71–100%) and precision (RSD < 6.0%), respectively. Among the 20 farmgate and market samples subjected to different techniques, imidacloprid residues were detected in four bitter gourd samples ranging from 0.042 to 0.099 mg kg − 1 in LC-MS and 0.050–0.10 mg kg − 1 for three samples in GST-based biosensor techniques. Food Science & Technology Insecticide bitter gourd Glutathione-S-Transferase biosensor GC-MS/LC-MS food safety Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 1. Introduction Bitter gourd ( Momordica charantia L.) is well known and demanded vegetable among cucurbits grown in India. During 2021-22, India produced 12.96 lakh metric tonnes of bitter gourd and cultivated in 1.07 lakh hectares (Indiastat, 2022 ). The extent of losses in bitter gourd may range from 30 to 100%, depending on the pest infestation (Kumari et al., 2021 ). Therefore, insecticides are necessary and important in modern-day agricultural practices for pest management in vegetable cultivation. However, the application of insecticides indiscriminately, especially during the fruiting stage, and failure to adopt safe waiting period result in the accumulation of pesticide residues in marketable vegetables (Rani et al., 2021 ; Upadhayay et al., 2020 ). Thus, detection and quantification of insecticide residues in fruits and vegetables have become essential requirement for consumers, producers and food quality control authorities. During the last two decades, synthetic pyrethroids (lambda-Cyhalothrin, Deltamethrin, Fenvalerate, etc.,) and neonicotinoid (imidacloprid, acetamiprid, thiacloprid, clothianidin etc.,) have become a predominant class of insecticides used against pests in agricultural lands, gardens, and houses, accounting for 25–30% of the insecticide market, worldwide (Demeneix et al., 2020 ; Hladik et al., 2016 ; Soderlund, 2008 ). Glutathione S-Transferase (GST) is a multigenic family of cytosolic proteins involved in multiple biological roles like, biotransformation of chemicals, reducing oxidative stress and cell regulatory mechanisms in major living organisms (Strange et al., 2001 ; Friedman, 2011 ). GST-mediated detoxification in insects can occur directly (phase I) or through the metabolism of secondary metabolites produced by other detoxification enzymes (phase II), (Kostaropoulos et al., 2001 ; Shou-Min, 2012 ). The primary detoxification process in insects is GST catalysed reaction of formation of thioether conjugates between insecticides compounds and endogenous tripeptide glutathione (GSH) (Enayati et al., 2005 ; Noori et al., 2020 ). Thus in-vitro study of the GST catalysed reaction is important not only to understand the molecular basis of insecticide resistance but also to develop protocols for detection and quantification of those pesticides and could be used in developing biosensor (Choi et al., 2003 ; Singh et al., 2009 ). The most popular conventional techniques such as GC, HPLC, GC-MS, LC-MS, UV-spectrophotometry and ELISA (Tankiewicz and Berg, 2022 ; Harshit et al., 2017 ; Watanabe, 2015 ) are used for detecting and quantification insecticides residue in food samples. These conventional techniques are time-consuming, labour-intensive, and need sophisticated equipment as well as proper sample preparation (Beitollahi et al., 2020 ; Xie et al., 2021 ; Kaur and Singh, 2020 ; Kalyani et al., 2021 ). The enzyme inhibition based electrochemical biosensors are suitable approach due to their capabilities of quick detection, reliability, less expensive, no/less sample preparation and feasibility. The development of bioanalytical methods and biosensors for different classes of pesticide residues using various kinds of enzymes, including acetylcholinesterase, choline oxidase, organophosphate hydrolase and tyrosinase (Thakkar et al., 2019 ; Yotova and Medhat, 2012; Lee et al., 2010 ; Anh et al., 2004 ). It is challenging to develop unique enzyme or bioreceptor molecules for each class of chemicals due to the class specificity of enzyme action on the one hand and the availability of several classes of pesticides in the market on the other hand (Bucur et al., 2018 ; Karadurmus et al., 2021 ). A recent report revealed that the electrochemical biosensor method can be employed to evaluate the GST catalysed interaction between GSH and CDNB as well as the influence of the effect on insecticidal reaction. The present work is on the development of protocols for detection and quantification of synthetic pyrethroid (lambda cyhalothrin, deltamethrin and fenvalerate) and neonicotinoid (imidacloprid, thiamethoxam and acetamiprid) insecticides GST-based biosensor probes detection. Inhibition kinetics of the six insecticides were studied and the method has been validated through analysis of bitter gourd sample and results were compared with GC-MS/LC-MS. 2. Materials and methods 2.1. Materials Glutathione-s-transferase (GST) (from equine liver), 1-chloro-2,4-dinitrobenzene (CDNB), reduced glutathione (GSH), bovine serum albumin (BSA), glutaraldehyde (25%), gelatin, N,N-dimethylformamide (DMF), 3-mercaptopropionic acid (3-MPA), synthetic pyrethroid (lambda-cyhalothrin, deltamethrin and fenvalerate) and neonicotinoid (Imidacloprid, acetamiprid and thiamethoxam) insecticides were purchased from Sigma Aldrich, India. LC-MS grade methanol (MeOH) (Fisher chemical, USA), disodium hydrogen phosphate (dibasic) (Na 2 HPO 4 ), sodium dihydrogen phosphate (monobasic) (NaH 2 PO 4 .H 2 O), NaCl and ethanol were procured from Merck, India, cellulose membrane (10 µ pore size) (Hi media) and potentiometer (Systronics µ pH system), Glass Membrane Electrode (GME) and Ag/AgCl electrode were purchased from Systronics, India. Glassy Carbon Electrode (GCE) as working electrode, platinum wire (Pt) as counter electrode, Ag/AgCl active as reference electrode and also polishing kits were purchased from Labkarts (India). Ultrapure water (18.2 MΩ) from a lab-scale (Q3 Merck) Millipore unit was used throughout the analysis. 2.2. Preparation of standard solutions Imidacloprid, thiamethoxam and acetamiprid stock solutions (400 mg/L) were prepared in acetonitrile (LC-MS grade) by weighing 10.17, 10.11 and 10.12 mg of analytical standards into a calibrated (Class A) volumetric flask (25 ml). Lambda cyhalothrin, deltamethrin and fenvalerate were prepared by dissolving 10.17 mg, 10.01 mg and 10.06 mg respective analyte in 25 ml acetonitrile to prepare 400 mg/L of primary stock solutions. The intermediate standards (40 mg/L) were prepared by transferring 2.5 ml from the stock solution (400 mg/L) into a 25 ml volumetric flask and the volume was made with respective solvent. Serial dilution from the intermediate standard solution was made in the range of 0.0025–0.5 mg/L. Matrix match standard solutions were prepared at concentration of 0.01, 0.025, 0.05, 0.075, 0.1 and 0.25 mg/L. All standard solutions were kept in a -20 0 C freezer for further use. 2.3. Instrumentation Potentiometric experiments were carried out on digital potentiometer connected with modified glass membrane working electrode and Ag/AgCl reference electrode. Amperometric measurement was achieved using an electrochemical workstation (BioLogic, VSP-300, France). All electrochemical protocols were performed and recorded with a computer interfaced to a BioLogic electrochemical analyser and EC-Lab (V10.44) software. In this instrument two-compartment with three-electrode system was used for the measurement. Glassy carbon electrode, platinum electrode and Ag/AgCl electrode were used as working electrode, counter electrode and reference electrode, respectively. Data obtained by Cyclic Voltammetry (CV) was analysed with the software Origin 9.5 (OriginLab Corporation), using linear models to fit data from current vs potential. Glassy carbon electrode was polished with aqueous slurry containing 0.3 mm of alumina powder before use and rinsed with deionized water followed by acetone. UV Visible spectra were recorded by using spectrophotometer (Shimadzu, Japan). The synthetic pyrethroid residues in bitter gourd was detected in GC (Shimadzu 2010) and the confirmed in GC-EI-MS (Shimadzu, QP 2010 plus). The GC-EI-MS analytical method validated with DB-1MS analytical capillary column (30 m × 0.25 mm × 0.25 µm) for residue analysis. Neonicotinoid insecticide residues were determined by validated method in Shimadzu 2020 series LC-MS (single quadrupole) containing reverse phase C18 (Shim pack- Shimadzu) column (250 mm length x 4.6 mm id, 5 µm particle size). 2.4. Preparation of electrochemical biosensor The electrode surface was modified by immersion for 60 min in 3-MPA (1.0×10 − 2 mol L − 1 ) ethanol solution and ultrapure water was used to remove unwanted impurities. The mixture of BSA (4 mg), gelatin (10%) with glutaraldehyde (2.5%) was vortexed and GST enzyme with N, N-dimethylformamide (DMF) (1%) were added to the mixture for gelation process. Further, mixture (10 µl) was immobilised over cellulose membrane and placed on GCE and GME. The immobilised electrode was dried and kept at 4 0 C. 'O' ring made of silicone was used for the attachment of immobilised membrane to the GME. 2.5. Analytical procedure 2.5.1. Spectrophotometric measurement The substrates CDNB and GSH conjugate in the presence of GST produce yellow-colored product (2,4-dinitrophenyl) S-glutathione, which is having absorbance at 340 nm. Presence of insecticides reduce catalytic activity of GST and substrate conjugation reaction interfering the UV absorbance. The transformation of substrate into a yellow product gets reduced in the presence of inhibitor and vice versa (Choi et al., 2003 ). Enzyme activity was calculated using parameters like Michaelis constant ( K m ) and maximum reaction velocity ( V max ) through Lineweaver-Burk (LB) plot (Schnell and Maini, 2003 ; Ellman et al., 1961 ). V max is the maximum reaction rate at the state where the enzyme is fully saturated by its substrate. K m is the concentration of substrate at half of V max (Yanuar, 2001 ; Ismail, 2021). The K m and V max are obtained from the graph of reaction rate (1/V) vs. substrate concentration (1/S). Enzyme activity was analysed by the addition of 50 µl GST into cuvette containing mixture of 5 mM CDNB + 5 mM GSH + 0.1 M phosphate buffer (950 µl). The absorbance at a wavelength of 340 nm for 10 min at 30 sec intervals was measured in the UV- VIS spectrophotometer. The catalytic inhibition reaction was measured by adding 50 µl of synthetic pyrethroid and neonicotinoid standards (0.01–0.5 ppm) into cuvette containing GSH mixture and the absorbance was recorded at 340 nm (Borah et al., 2017 ). 2.5.2. Potentiometric measurement A digital potentiometer was connected with modified glass membrane working electrode and Ag/AgCl reference electrode, potential signal was measured on the digital display of the potentiometric instrument. The total volume of the working solution in the reaction cell was 5 ml containing 5 mM of GSH in phosphate buffer and 5 mM CDNB (1:1). The solution mixture was stirred to measure the initial potential. Further, insecticide standard was added into reaction cell ranging from lower (0.01 mg kg − 1 ) to higher concentration (0.5 mg kg − 1 ) and the potential was measured within 0–15 min. 2.5.3. Amperometric measurement The electrochemical workstation consists of glassy carbon electrode as working electrode, platinum wire counter electrode and Ag/AgCl reference electrode. Five ml of GSH and CDNB mixture (1:1) taken into reaction cell was used as analytical solution for catalytic reaction. Selected synthetic pyrethroid and neonicotinoid insecticides in different concentration of 0.01 to 0.5 mg kg − 1 were added to the test solution and measured through CV technique. CV was performed at a scan rate of 20 mV.s − 1 by applying a linear potential scan between − 0.5 to + 1.0 mV (vs. Ag/AgCl). 2.6. Analysis of selected insecticides in bitter gourd using electrochemical biosensor Ten-gram of homogenised bitter gourd sample was taken in 50 ml centrifuge tube and 20 ml of acetonitrile was added. The mixture was shaken for 2 min. and 3 ml of aliquot was used for determination of residues in enzymatic biosensor. Initial current of test solution was measured using 5 mM GSH and CDNB substrate in 3 ml of acetonitrile (25%) solvent in reaction cell. Further, sample solution current was measured and per cent of inhibition was calculated using the following formula (Tang and Wu, 2014 ), I 1 – I 2 I (%) = × 100 I 1 Where, I (%) – percentage of inhibition, I 1 - current values before inhibition (mV), I 2 - current values after inhibition (mV). 2.7. Chromatographic measurement The residues of lambda cyhalothrin, deltamethrin, fenvalerate, imidacloprid, thiamethoxam, and acetamiprid residues were extracted and cleaned up from bitter gourd fruit by modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) method (Anastassiades et al., 2003 ). Ten gram sample was taken in 50 ml polypropylene centrifuge tube along with 20 ml acetonitrile and vortexed for one min. Then four grams of anhydrous magnesium sulphate and one gram of sodium chloride were added, vortexed and centrifuged for 10 min. at 6000 rpm. After centrifugation, the upper acetonitrile layer (10 ml) was passed through anhydrous sodium sulphate (4 g) to remove any remaining moisture. A six-millilitre of supernatant was transferred into a 15 ml centrifuge tube containing PSA (150 mg), GCB (25 mg) and MgSO 4 (900 mg), vortexed for one min. and centrifuged at 3000 rpm for 10 min. A portion of acetonitrile (4 ml) phase was carefully pipetted out in to a clean glass tube and evaporated to near dryness using turbovap LV (35 0 C) with a gentle stream of nitrogen. The residues were then redissolved in one millilitre of respective solvent, filtered through a 0.2 µm PTFE syringe filter (Agilent, USA). The final volume was reconstituted to about one ml using n-hexane for GC-MS analysis and methanol for LC-MS analysis. 2.8. Validating the method for detection of selected insecticides The effectiveness of the analytical method for the detection of multi-residue (lambda cyhalothrin, deltamethrin, fenvalerate, imidacloprid, thiamethoxam and acetamiprid) analysis of insecticides were standardised in bitter gourd sample using electrochemical biosensor and GC-MS/LC-MS and validated through parameters such as linearity, sensitivity, recovery precision and matrix effect (SANTE, 2022). Linearity The standard linearity curve was obtained by analysing seven different concentrations of selected insecticides ranging from 0.005 to 0.5 mg kg − 1 in biosensor and GC-MS/LC-MS with six replications. The matrix match linearity of calibration curve was established in the range of 0.01 to 0.25 mg kg − 1 for synthetic pyrethroids and neonicotinoids. The linear relationship and coefficient of variation were calculated through response of current signal in biosensor. Sensitivity The enzymatic biosensor was evaluated using 3 ml phosphate buffer (0.1 M) test solution with insecticide standard and replicated thrice. A calibration graph of current versus analyte concentration was constructed to establish the slope and linear range. Limit of Detection (LOD) and Limit of Quantification (LOQ) were calculated in GC-MS/LC-MS by injecting the matrix match standards of synthetic pyrethroid and neonicotinoid insecticides starting from lowest concentration level. The LOD and LOQ were calculated with the following equations, LOD = 3× standard deviation / slope LOQ = 10 × standard deviation / slope Recovery Electrochemical biosensor techniques Untreated bitter gourd samples were cut into small piece and homogenised. A sample of 10 g was spiked at five different concentrations of selected insecticides with three replications. Recovery (%) was calculated by comparing the current response of the known quantity of analytes in the fortified sample and spiked matrix match sample. Chromatography techniques Homogenized untreated bitter gourd fruit samples (10g) were spiked at five different concentrations of lambda cyhalothrin, deltamethrin and fenvalerate (0.01, 0.025, 0.05, 0.075 and 0.1 mg kg − 1 ), imidacloprid, thiamethoxam and acetamiprid (0.025, 0.05, 0.075,0.1 and 0.25 mg kg − 1 ) with six replications. Recovery (%) was calculated by comparing the peak area of the known quantity of analytes in the fortified sample (prior extraction) and spiked matrix match sample (after extraction). Precision The precision of the method was evaluated by determining the Relative Standard Deviation (RSD) at each spiking level (0.01 to 0.25 mg kg − 1 ) of bitter gourd fruit sample. 2.9. Monitoring of market and farmgate samples of bitter gourd for insecticides residues Twenty samples of bitter gourd were collected from market and farmgate of Coimbatore and nearby areas. The samples were labelled, brought to laboratory, homogenised and stored at -4 0 C for further analysis. The samples were analysed for the presence of synthetic pyrethroid and neonicotinoid residues using electrochemical biosensor and the results are compared to GC-MS/LC-MS. 3. Results and Discussions 3.1. Glutathione -S- Transferase (GST) enzyme activity Spectrophotometric analysis showed significant absorbance of GSH and CDNB substrate solution at 320 nm wavelength (Fig. 1 ). Lineweaver-Burk Plot (LB) of reaction rate (1/V) vs. substrate (1/S) concentration in the presence and absence of synthetic pyrethroid and neonicotinoid are shown in Fig. 2. The results of GST inhibited by synthetic pyrethroid (lambda cyhalothrin, deltamethrin and fenvalerate) and neonicotinoid (imidacloprid, thiamethoxam and acetamiprid) insecticides are given in Table 1 . Based on the conjugation reaction of the reduced GSH and CDNB substrate, Michaelis-Menten constant ( K m ) and maximum velocity ( V max ) were calculated to be 0.00154 M and 0.01329 mM/s. Kinetic reaction measured in terms of V max of substrate in the presence of selected insecticides at 0.01 to 0.5 mg kg − 1 were 0.01519–0.05249 mM/s and the value of K m were 0.00178–0.00767 M, respectively. K m for the immobilised GST enzyme with graphene oxide-gelatin matrix was 0.083 mmol L − 1 . The slope (1/ V max ) vs. substrate concentration provided a linear curve with K i values of 219.29 mM for chlorpyriphos, 54.82 mM for ethion and 21.27 mM for DDT (Borah et al., 2018 ). Table 1 Kinetic parameters of GST in presence and absence of inhibitors S.No. Insecticides R 2 K m (M) V max (mM/s) 1. Substrate (GSH + CDNB) 0.99 0.00154 0.01329 2. Lambda cyhalothrin 0.98 0.00329 0.03629 3. Deltamethrin 0.98 0.00636 0.03635 4. Fenvalerate 0.99 0.00767 0.05249 5. Imidacloprid 0.99 0.00178 0.03109 6. Thiamethoxam 0.99 0.00194 0.01519 7. Acetamiprid 0.98 0.00509 0.01797 Km -Michaelis-Menten, Vmax -maximum velocity, R 2 - Correlation coefficient The results indicated that K m and V max value of enzyme-insecticide-substrate complex were higher than enzyme-substrate complex. Therefore, obtained results showed higher affinity of inhibitors to the GST enzymes. In the present study, the curve on the plot intersected in the second quadrant, is a characteristic behaviour of fully mixed inhibition (Ribeiro et al., 2022 ; Albuquerque and Ferreira, 2007 ; Hofer and Fringeli, 1981 ). This type of inhibition occurs when the inhibitor is capable of binding to both free enzyme and to the enzyme-substrate complex. Figure 2. Lineweaver-Burk Plot of substrate (GSH-CDNB) and various insecticides 3.1.1. Optimization of the measurement conditions The insecticide detection based on measurement of GST dependent on the enzyme catalytic reaction. The amount of enzyme and its substrate are crucial for enzymatic reaction and are to be optimised for measurement of insecticide residues. LB plot showed the good relationship between enzyme and substrate with good linearity (> 0.98) in the range of 0.01 to 0.5 mg kg − 1 at 2 U of GST enzyme. A rise of absorbance was observed when the concentration of substrate increased from 1 to 7 mM. For the detection of insecticide residues, 2 U enzyme with 5 mM GSH-CDNB level was optimised. 3.2. Method validation of developed biosensor for detection of selected insecticides The effectiveness of the analytical method used for synthetic pyrethroid (lambda cyhalothrin, deltamethrin and fenvalerate) and neonicotinoid (imidacloprid, thiamethoxam and acetamiprid) insecticide residue analysis was standardized for bitter gourd matrix. The results of method validation parameters such as linearity, sensitivity, recovery and precision are discussed below. 3.2.1. Potentiometric measurement Potentiometric instrument measures the potential differences caused by ions in an electrochemical reaction that correlates with the concentration of analyte (Renault, 2001 ; Rostiyanti and Mubarok, 2021 ). The correlation coefficient (R 2 ) value was above 0.98 for the linearity standard of synthetic pyrethroid and neonicotinoid insecticides in the concentration ranging from 0.01 and 0.5 mg kg − 1 and RSD was less than 11 per cent (Table 2 ). LOD and LOQ were 0.01 and 0.05 mg kg − 1 respectively. The LOQ of the biosensor was calculated based on enzyme inhibition rate which ranged from 16.22 to 30.05 per cent (Table 3 ). The mean per cent recovery of selected insecticides in bitter gourd fruits were in the range of 75.85 to 98.72 with RSD less than 4.0 per cent at concentration 0.01–0.5 mg kg − 1 (Table 4 ). The linearity and recovery experiments showed inhibition percentages ranging from 3.19 to 65.10 (Fig. 3 ). The results demonstrate that the inhibition ability of fenvalerate was the strongest and that of lambda cyhalothrin was the weakest among the selected insecticides. Table 2 Analytical data of synthetic pyrethroid and neonicotinoid insecticides by potentiometric method Parameters Substrate (GSH + CDNB) Lambda cyhalothrin Deltamethrin Fenvalerate Imidacloprid Thiamethoxam Acetamiprid Response time (min) 5 10 10 10 10 10 10 Linearity range 1–7 mM 0.01–0.5 ppm 0.01–0.5 ppm 0.01–0.5 ppm 0.01–0.5 ppm 0.01–0.5 ppm 0.01–0.5 ppm Regression line y = 7.6429x + 4.2857 y = 8.5305x + 4.9062 y = 34.211x + 0.5246 y = 7.8773x + 0.6463 y = 10.405x + 0.0678 y = 5.5046x + 1.906 y = 16.581x − 3.5004 Correlation coefficient 0.998 0.981 0.984 0.983 0.985 0.991 0.993 LOD (ppm) - 0.01 0.01 0.01 0.01 0.01 0.01 LOQ (ppm) - 0.05 0.05 0.05 0.05 0.05 0.05 RSD (%) 1.24–5.55 1.19–6.94 0.60–6.87 0.63–7.22 0.58–5.23 0.61–9.31 0.59–10.52 GSH- reduced glutathione, CDNB-1-chloro-2,4-dinitrobenzene, LOD- Limit of Detection, LOQ-Limit of Quantification, RSD- Relative Standard Deviation Table 3 Percentage inhibition of GST for selected insecticides in potentiometric method Concentration (mg/kg) Lambda cyhalothrin Deltamethrin Fenvalerate Imidacloprid Thiamethoxam Acetamiprid 0.01 4.58 10.40 14.12 3.08 5.23 3.19 0.025 10.99 16.66 22.72 10.25 12.45 10.99 0.05 16.55 29.04 30.05 16.22 20.27 17.23 0.075 22.96 32.59 38.13 24.81 28.88 26.64 0.1 30.74 40.34 46.28 31.09 32.85 32.85 0.25 37.26 49.08 55.35 38.72 40.14 40.84 0.50 45.68 56.47 65.10 46.40 48.56 48.20 Table 4 Recovery percentage of synthetic pyrethroid and neonicotinoid insecticides in bitter gourd by potentiometric method Synthetic pyrethroid Neonicotinoid Insecticide/ Spiked concentration (mg kg − 1 ) Mean recovery (%) ± SD RSD (%) Insecticide/ Spiked concentration (mg kg − 1 ) Mean recovery (%) ± SD RSD (%) Lambda cyhalothrin Imidacloprid 0.05 95.22 ± 2.43 2.56 0.05 94.46 ± 1.83 1.94 0.075 98.72 ± 1.43 1.45 0.075 88.19 ± 2.89 3.27 0.1 85.15 ± 0.97 1.14 0.1 95.07 ± 3.71 3.90 0.25 76.53 ± 0.85 1.17 0.25 98.65 ± 1.08 1.08 0.5 83.31 ± 2.84 3.41 0.5 79.26 ± 0.83 1.04 Deltamethrin Thiamethoxam 0.05 91.55 ± 0.78 0.85 0.05 76.47 ± 1.48 1.94 0.075 93.05 ± 0.65 0.69 0.075 84.07 ± 2.29 2.72 0.1 96.38 ± 2.08 2.16 0.1 75.49 ± 2.21 2.93 0.25 87.67 ± 2.38 2.71 0.25 91.75 ± 3.17 3.46 0.5 92.00 ± 2.21 2.40 0.5 98.38 ± 1.03 1.04 Fenvalerate Acetamiprid 0.05 81.85 ± 0.88 1.08 0.05 94.81 ± 1.59 1.68 0.075 78.81 ± 2.79 3.54 0.075 81.47 ± 1.70 2.09 0.1 82.28 ± 2.18 2.65 0.1 82.97 ± 2.81 3.39 0.25 82.56 ± 1.51 1.82 0.25 87.89 ± 3.02 3.45 0.5 95.74 ± 1.94 2.03 0.5 93.98 ± 2.26 2.41 *Mean of three replications, SD- Standard Deviation, RSD- Relative Standard Deviation 3.2.2. Amperometric measurement Amperometric biosensors generally measure the variations in current based on electroactive chemical reaction between the recognition component and the analyte (Sadullayeva and Rakhmatov, 2022 ). Cyclic Voltammetry (CV) was carried out from − 0.5 to + 1 mV with scan rate of 20 mV/s in phosphate buffer solution at pH 7.0. The sharpness of peaks in CV indicated the well binding of enzyme layer onto the GCE surface (Fig. 4 ). The Cyclic Voltammetry (CV) responses of different concentration of substrate (GST-CDNB) in potential window range of -0.5 to + 1 mV, recorded at a scan rate of 20 mV/s are shown in Fig. 4 . The linearity of the calibration curves for substrate (GST-CDNB) was established with seven levels of concentration (1–7 mM) having significant R 2 value (0.99) and satisfactory RSD (0.75–2.60%) (Table 5 ). The R 2 value of more than 0.98 and RSD less than 10 per cent were obtained when the linearity range of selected insecticides were 0.01 to 0.5 mg kg − 1 . The LOD and LOQ for synthetic pyrethroid and neonicotinoid insecticides were 0.01 and 0.5 mg kg − 1 , respectively. The LOQ of the biosensor was calculated based on enzyme inhibition rate, which ranged from 22.24 to 32.00 per cent (Table 6 ). The mean per cent recovery of selected insecticides in bitter gourd fruits ranged from 71.44 to 99.04 with RSD less than 6.0 per cent at the concentration 0.01–0.5 mg kg − 1 (Table 7 ). The inhibition percentages ranged from 6.04 to 59.75 in linearity and recovery experiments (Figs. 5 & 6 ). These results indicated a good performance for determination of selected insecticides in bitter gourd samples. Borah et al. ( 2017 ) determined the LOD of insecticides temephos, dimethoate and fenbucarb using GST immobilised glassy carbon electrode as 0.002, 0.004 and 0.005 ppm respectively and R 2 of 0.99 for the linear range of 2–50 ppb. Table 5 Analytical data of synthetic pyrethroid and neonicotinoid insecticides by amperometric method Parameters Substrate (GSH + CDNB) Lambda cyhalothrin Deltamethrin Fenvalerate Imidacloprid Thiamethoxam Acetamiprid Response time (min) 5 10 10 10 10 10 10 Linearity range 1–7 mM 0.01–0.5 ppm 0.01–0.5 ppm 0.01–0.5 ppm 0.01–0.5 ppm 0.01–0.5 ppm 0.01–0.5 ppm Regression line y = 7.9746x + 12.756 y = 14.619x + 40.23 y = 6.6775x + 16.786 y = 6.3759x + 23.403 y = 2.8371x + 15.401 y = 2.2111x + 16.458 y = 8.6593x + 13.164 Correlation coefficient 0.996 0.982 0.981 0.989 0.992 0.986 0.986 LOD (ppm) - 0.01 0.01 0.01 0.01 0.01 0.01 LOQ (ppm) - 0.05 0.05 0.05 0.05 0.05 0.05 RSD (%) 0.75–2.60 0.63–9.79 0.75–9.18 1.89–7.05 0.98–6.39 1.66–9.45 1.14–5.69 GSH- reduced glutathione, CDNB-1-chloro-2,4-dinitrobenzene, LOD- Limit of Detection, LOQ-Limit of Quantification, RSD- Relative Standard Deviation Table 6 The percentage of inhibition of GST for selected insecticides in amperometric method Concentration (mg kg − 1 ) Lambda cyhalothrin Deltamethrin Fenvalerate Imidacloprid Thiamethoxam Acetamiprid 0.01 9.07 10.13 9.26 10.94 9.94 6.04 0.025 17.92 18.89 18.67 15.65 17.03 19.25 0.05 25.63 29.04 27.3 22.24 23.87 32.00 0.075 30.73 37.48 31.79 29.72 30.76 37.16 0.1 34.53 40.62 32.25 32.88 32.45 40.27 0.25 40.62 51.61 40.82 40.49 38.51 52.01 0.50 47.47 59.75 50.08 48.31 43.47 59.28 Table 7 Recovery percentage of synthetic pyrethroid and neonicotinoid insecticides in bitter gourd by amperometric method Synthetic pyrethroid Neonicotinoid Insecticide/ Spiked concentration (mg kg − 1 ) Mean recovery (%) ± SD RSD (%) Insecticide/ Spiked concentration (mg kg − 1 ) Mean recovery (%) ± SD RSD (%) Lambda cyhalothrin Imidacloprid 0.05 92.73 ± 0.96 1.03 0.05 92.93 ± 3.68 3.96 0.075 94.85 ± 1.27 1.34 0.075 78.23 ± 1.28 1.64 0.1 92.85 ± 2.58 2.78 0.1 99.04 ± 2.23 2.25 0.25 81.63 ± 3.75 4.59 0.25 81.37 ± 2.96 3.63 0.5 85.15 ± 2.97 3.49 0.5 77.74 ± 2.86 3.68 Deltamethrin Thiamethoxam 0.05 93.51 ± 3.29 3.52 0.05 80.59 ± 2.00 2.48 0.075 77.33 ± 1.93 2.47 0.075 78.24 ± 3.83 4.89 0.1 77.23 ± 1.14 1.48 0.1 81.63 ± 1.99 2.44 0.25 76.15 ± 4.35 5.72 0.25 87.99 ± 1.67 1.90 0.5 71.44 ± 1.21 1.69 0.5 81.92 ± 3.52 4.29 Fenvalerate Acetamiprid 0.05 75.13 ± 1.88 2.51 0.05 77.89 ± 3.03 3.89 0.075 73.76 ± 3.54 4.79 0.075 97.75 ± 1.85 1.89 0.1 84.41 ± 2.47 2.92 0.1 94.40 ± 1.29 1.36 0.25 86.48 ± 4.77 5.51 0.25 96.09 ± 3.29 3.43 0.5 81.71 ± 3.03 3.71 0.5 80.12 ± 0.77 0.96 *Mean of three replications, SD- Standard Deviation, RSD- Relative Standard Deviation The CV results of GST reaction as depicted in Fig. 4 showed strong oxidation peak with addition of the substrate (GSH + CDNB) and the magnitude of the anodic current ( E p = + 75 µA (vs. Ag/AgCl)) was higher than in the absence of substrate ( E p = + 8 µA). The CV results are depicted in Fig. 5 , the prominent redox peaks were observed for the biosensor before inhibition. After inhibition by selected insecticides relative decrease in anodic current was observed (5–40 µA) and peak potential range of + 600 and + 850 mV (vs. Ag/AgCl) was obtained. The peak currents of electrochemical reaction were indirectly proportional to the insecticide concentration and further an increase in the insecticide concentration leads to decrease in the peak current. The observed CV behaviour of GST enzyme with substrate (GSH + CDNB) could be explained with the following reaction mechanism. Enzyme-substrate complex in organic solvent dissociates into COH and CO − ions. The CO − thus produced interacts with GSH to produce electro active intermediate. Under electrochemical process in which CO − formed from oxidation at higher potential (0.90 V) triggers the reaction of GSH (Borah et al., 2016 ). 3.2.3. Optimization of experimental parameters In the electrochemical study, enzyme was immobilised in cellulose membrane connected to glass membrane and glassy carbon electrode integrated with transducer signal of potentiometer and potentiostat/ galvanostat. Working of biosensor is highly influenced by the type and thickness of membrane as they are the supporting material for working electrode of biosensor (Reybier et al., 2002 ; Bucur et al., 2018 ). The most important step in the development of an enzyme biosensor is the stable attachment of enzyme to the surface of working electrode. It was governed by various interactions between enzyme and electrode surface for improved response, stability and reproducibility (Ivanov et al., 2010 ; Rodrigues et al., 2022 ). According to research, GST enzyme based biosensor designed for detection of selected insecticides works in the range of 600–850 mV. This over potential may affect the activity of enzyme resulting in poor biosensing performance and instability of the biosensor. Moreover, high working potential can cause oxidation of other species present in the media (Raghu et al., 2014 ). Thus, possible lower potentials are preferred in amperometric systems. To overcome the problem, immobilization materials could be achieved using electrochemical mediators onto the transducers. In this system, combination of different techniques such as cross-linking, entrapment, covalent binding and adsorption are used. The cellulose membrane was used as the supporting material for glass membrane and glassy carbon electrode and immobilization of enzyme GST by the process of cross-linking, entrapment and adsorption using Bovine Serum Albumin (BSA) (4 mg), glutaraldehyde (2.5%) and gelatin (10%). The combination-based GST immobilisation was reported to be more effective than one based glutaraldehyde or BSA alone (Pohanka and Skladal, 2008 ; Rekha and Murthy, 2008 ). The interaction energy that occurs between enzyme-substrate-inhibitor increases the conductive area and electron-transfer rate between the electrode surface and analyte. Linearity between the reaction of the enzyme modified electrode and the anodic peak current of oxidation was good, which resulted due to a controlled diffusion process (Mashuni et al., 2021 ; Kesik et al., 2014 ). These findings support high electrooxidation ability of the enzyme-modified electrode towards insecticides, which showed synchronised electrochemical response. The developed biosensor was tested at different working potentials for the 2.0 U GST with 5 mM of substrate to investigate optimum working potential. As illustrated in Fig. 7 , the amperometric response was recorded at different scan rates (20-100 mV/s) applied potential versus Ag/AgCl wire reference electrode. It can be seen that the potential response increases with scan rate increasing within 20-100 mV. Optimum inhibition rate was obtained with the scan rate of 20 mV/s for all insecticides. To examine the relationship between amount of enzyme and biosensor response, biosensors was prepared with different GST concentration between 0.5 U and 2.0 U where other components were kept constant. As seen in Fig. 4 , the highest signal was recorded with 2.0 U GST. In case of excess loading of enzyme, the enzyme molecules leached from the surface since adsorbed enzyme was not sufficiently stable on the limited electrode area (Cesarino et al., 2014). On the other hand, if substantial amount of biomolecule could not be immobilized onto the electrode, biosensor responses decreased due to inadequate enzymatic reaction which leads to low sensitivity (Songa and Okonkwo, 2016 ). Sufficient working stability and reasonable signals were achieved with 2 U GST. Low pesticide concentrations could not be detected and the response decreased at low substrate concentrations. The percentage of inhibition was evaluated from the response of the active and inhibited forms of the enzyme. Therefore, all the enzyme molecules in the medium have to take part in the reaction and this could only be possible in substrate concentrations corresponding to the saturation portion of the activity versus substrate (GSH) curves. High substrate concentrations (5 mM) were then selected for use in further studies, namely for entrapped 2 U GST immobilized enzymes (Fig. 4 ). Under such conditions, the inhibition mechanism is mixed inhibition, so that the substrate would compete/non-compete with the analyte for the enzyme active site and inhibition, especially at low analyte concentrations could be detected. Insecticide concentrations ranging from 0.01 to 0.5 ppm were tested in terms of their effect on enzyme activity at different incubation times in pesticide solution (5, 10, 15 and 20 min). It can be seen that (Fig. 5 ) level of inhibition of the enzyme increased with increasing incubation period until reaching a plateau level. The GST immobilized enzyme system responds to the presence of the insecticide more quickly than the entrapped form. The decrease in activity was less pronounced beyond 10 min for both systems and therefore, the incubation time was selected as 10 min. 3.3. Validation of multi-residue analysed method using GC-MS/LC-MS The effectiveness of the analytical method used for multi-residue insecticide analysis was standardized for bitter gourd matrix as per SANTE guidelines (SANTE, 2021 ). Excellent linear relationships and correlation coefficients (R 2 > 0.99) for lambda cyhalothrin, deltamethrin, fenvalerate, imidacloprid, thiamethoxam and acetamiprid in solvent and matrix match standard were observed (Table 8 and Fig. 8 ). The LOD and LOQ for synthetic pyrethroid were 0.0025 and 0.01 mg kg − 1 and 0.0075 and 0.025 mg kg − 1 for neonicotinoids, respectively. Recovery ranged between 76.70-104.20 per cent, with an RSD less than seven per cent (Table 9 and Fig. 9 ). The matrix effect was within 0.68–10.26 per cent of the spiked standards (Table 8 ). Matrix effect values were less than 11 per cent in both matrices, indicating that the samples had no apparent matrix effect and that the cleanup effect was adequate. These results suggested that the method provided repeatable and reliable results with acceptable recovery. Table 8 Linearity parameters and matrix effect for selected insecticides in bitter gourd Insecticides Calibration (matrix) Calibration range (mg/L) Regression equation Correlation coefficient (R 2 ) Matrix effect (%) Lambda cyhalothrin Solvent 0.0025-0.1 y = 7E + 06x + 67004 0.993 - Fruit 0.01–0.1 y = 125677x − 121395 0.991 0.68–6.69 Deltamethrin Solvent 0.0025-0.1 y = 5E + 06x + 35242 0.997 - Fruit 0.01–0.1 y = 101004x − 83609 0.993 1.11–3.92 Fenvalerate Solvent 0.0025-0.1 y = 6E + 06x + 11374 0.997 - Fruit 0.01–0.1 y = 112784x − 112367 0.985 0.83–3.41 Imidacloprid Solvent 0.005–0.25 y = 2E + 06x + 25602 0.997 - Fruit 0.025–0.25 y = 1E + 06x − 4682.1 0.997 1.10–5.62 Acetamiprid Solvent 0.005–0.25 y = 8E + 06x + 81868 0.994 - Fruit 0.025–0.25 y = 2E + 06x − 6549.1 0.997 1.89–8.97 Thiamethoxam Solvent 0.005–0.25 y = 912330x + 13711 0.995 - Fruit 0.025–0.25 y = 1E + 06x + 6632.1 0.995 1.91–10.26 Table 9 Recovery percentage of synthetic pyrethroid and neonicotinoid insecticides in bitter gourd by GC-MS/LC-MS Synthetic pyrethroid Neonicotinoid Insecticide/ Spiked concentration (mg kg − 1 ) Mean recovery (%) ± SD RSD (%) Insecticide/ Spiked concentration (mg kg − 1 ) Mean recovery (%) ± SD RSD (%) Lambda cyhalothrin Imidacloprid 0.05 88.34 ± 1.71 1.93 0.05 95.86 ± 2.71 2.82 0.075 83.57 ± 2.02 2.43 0.075 99.90 ± 2.51 2.51 0.1 95.98 ± 1.03 1.07 0.1 99.93 ± 2.52 2.52 0.25 82.09 ± 5.43 6.62 0.25 95.83 ± 4.18 4.36 0.5 80.93 ± 3.87 4.79 0.5 101.32 ± 2.62 2.59 Deltamethrin Thiamethoxam 0.05 84.15 ± 1.97 2.34 0.05 98.65 ± 2.29 2.32 0.075 84.48 ± 1.89 2.23 0.075 102.89 ± 2.53 2.46 0.1 83.61 ± 2.46 2.94 0.1 97.58 ± 4.21 4.27 0.25 85.42 ± 1.63 1.91 0.25 98.58 ± 2.19 2.22 0.5 77.85 ± 0.23 0.29 0.5 104.20 ± 2.79 2.68 Fenvalerate Acetamiprid 0.05 82.55 ± 2.20 2.67 0.05 89.95 ± 1.11 1.23 0.075 76.70 ± 1.59 2.08 0.075 95.40 ± 2.50 2.62 0.1 83.47 ± 1.83 2.19 0.1 99.68 ± 4.00 4.01 0.25 80.95 ± 2.29 2.82 0.25 96.18 ± 3.13 3.25 0.5 77.58 ± 1.36 1.76 0.5 102.17 ± 1.65 1.62 *Mean of three replications, SD- Standard Deviation, RSD- Relative Standard Deviation 3.4. Monitoring of market and farmgate bitter gourd samples for insecticides residues Biosensor based detection method was validated by performing a twostep experiment. In first step the linearity, recovery, LOD and LOQ of the developed biosensor in bitter gourd sample were determined. In the second step, bitter gourd samples collected from farmgate and market were subjected to bioanalysis using developed biosensor and the results were compared with GC-MS/LC-MS) (Table 10 ). The monitoring results showed that four out of twenty bitter gourd samples were found to have detectable residues of imidacloprid residues (LOQ-0.025 mg kg − 1 ) in LC-MS. The samples were found to contain imidacloprid residues in four samples ranging from 0.011–0.055 mg kg − 1 . In none of the sample imidacloprid residues exceeded MRL level set by the European Union (EU, 2022). The EU MRL for imidacloprid in bitter gourd is 0.2 mg kg − 1 . Table 10 Detection of selected insecticides residues in market and farmgate bitter gourd samples using different analytical methods S. No. Sample Insecticides GC/LC-MS (mg kg − 1 ) Potentiometric method Amperometric method Inhibition (%) Residue (mg kg − 1 ) Inhibition (%) Residue (mg kg − 1 ) 1. Sample 1 ND - - - - - 2. Sample 2 ND - - - - - 3. Sample 3 ND - - - - - 4. Sample 4 Imidacloprid 0.060 43.00 0.051 28.56 0.063 5. Sample 5 Imidacloprid 0.058 42.20 0.050 24.55 0.055 6. Sample 6 ND - - - - 7. Sample 7 ND - - - - 8. Sample 8 ND - - - - 9. Sample 9 ND - - - - 10. Sample 10 Imidacloprid 0.042 BLQ BLQ BLQ BLQ 11. Sample 11 ND - - - - - 12. Sample 12 ND - - - - - 13. Sample 13 ND - - - - - 14. Sample 14 Imidacloprid 0.099 76.37 0.090 45.17 0.10 Fenvalerate 0.010 BLQ BLQ BLQ BLQ 15. Sample 15 ND - - - - - 16. Sample 16 ND - - - - - 17. Sample 17 ND - - - - - 18. Sample 18 ND - - - - - 19. Sample 19 ND - - - - - 20. Sample 20 Fenvalerate 0.020 BLQ BLQ BLQ BLQ ND- Not Detected, BLQ-Below the Limit of Quantification - GC-MS (0.01 mg kg − 1 ), LC-MS (0.025 mg kg − 1 ) and Potentiometric/Amperometric methods (0.05 mg kg − 1 ) In potentiometric and amperometric methods, detection and quantification of insecticide residues in samples was standardized based on per cent inhibition in current at LOQ level (0.05 mg kg − 1 ). The per cent inhibition recorded was 16.55 and 25.63% lambda cyhalothrin, 20.04 and 29.04% deltamethrin, 30.05 and 27.30% fenvalerate, 16.62 and 22.24% imidacloprid, 20.27 and 23.87% thiamethoxam and 17.23 and 32.00% acetamiprid. By employing potentiometric technique, the residues of imidacloprid were detected in three bitter gourd samples ranged from 0.050–0.090 mg kg − 1 with respective inhibition percentages ranging from 42.20 to 76.37. In amperometric method, imidacloprid residues were found in three samples (0.055-0.10 mg kg − 1 ) and the corresponding inhibition percentages were in the range of 20.97–45.17. Borah et al. ( 2018 ) developed GST enzyme-based biosensor to detect residues of five insecticides in potato using amperometric method and compared with the results of GC-MS. LOD of amperometric method was calculated in carbendazim (0.002 ppm), chlorpyriphos (0.06 ppm), DDT (0.04 ppm), dinocap (0.05 ppm) and ethion (0.1 ppm) with 10 per cent inhibition. While, GC-MS analysis found LOD at 0.01 ppm and recovery rate of five insecticides ranged from 88 to 100 per cent in potato samples, whereas biosensor recovery from potato samples ranged from 25 to 101 per cent. The application of the developed biosensor analysis for monitoring bitter gourd samples were shown in the present study. The developed biosensor method does not require any sample extraction, clean up procedures, low cost and real samples can directly be analysed using biosensor probe. In GC-MS/LC-MS analysis, pre-treatment procedures were required before residue analysis and chromatographic methods for residue detection are generally laborious, time consuming and require expensive sophisticated instruments (Hassani et al., 2017 ; Zamora et al., 2019 ). Our study laid a foundation for the development of a biosensor-based device for in-situ detection of synthetic pyrethroid and neonicotinoid insecticide residues in harvested agricultural produce. Conclusion The standardised GST biosensor based method has the ability for the in-situ detection of insecticide residue in vegetable and it requires no clean-up and extraction steps. The method uses the GST catalyzed in vitro detoxification reaction between glutathione and 1-chloro-2,4-dinitrobenzene as the benchmark reaction. This biosensor can be employed for rapid detection of synthetic pyrethroid (lambda cyhalothrin, deltamethrin and fenvalerate) and neonicotinoid (imidacloprid, thiamethoxam and acetamiprid) residues. The detection accuracy of biosensor results was confirmed through GC-MS/LC-MS analysis. The average recovery, sensitivity and precision of synthetic pyrethroid and neonicotinoid detection in the actual samples of bitter gourd showed good potential for the application in food safety. Declarations CRediT authorship contribution statement M. M. Mawtham: Methodology, Investigation, Formal analysis, Writing-original draft, formal analysis, Visualization. K. Bhuvaneswari: Methodology, Conceptualization, Supervision, Writing-review & editing. S. Thirumalairajan: Resources, Investigation, Formal analysis. A. Suganthi: Resources, Supervision. S. Kulanthaisami: Resources, Investigation. K. S. Subramanian: Resources,Investigation. Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Acknowledgements The authors are thankful to the Pesticide Toxicology Laboratory, Department of Agricultural Entomology, Centre for Plant Protection Studies and Department of Nano Science & Technology, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India, for providing necessary facilities during the study. This work was supported by Jawaharlal Nehru Memorial Fund, New Delhi, India [SU-1/1454/2022-23/78]. Chemical compounds studied in this article: Lambda-Cyhalothrin (PubChem CID:443046 ) Deltamethrin (PubChem CID:40585 ) Fenvalerate (PubChem CID:3347 ) Imidacloprid (PubChem CID:86287518 ) Thiamethoxam (PubChem CID:107646 ) Acetamiprid (PubChem CID:213021 ) References Albuquerque YDT, Ferreira LF (2007) Amperometric biosensing of carbamate and organophosphate pesticides utilizing screen-printed tyrosinase-modified electrodes. Anal Chim Acta 596(2):210–221. https://doi.org/10.1016/j.aca.2007.06.013 Anastassiades M, Lehotay SJ, stajnbaher D, Schenck FJ (2003) Fast and easy multiresidue method employing acetonitrile extraction/partitioning and dispersive solid-phase extraction for the determination of pesticide residues in produce. J AOAC Int 86(2):412–431. https://doi.org/10.1093/jaoac/86.2.412 Anh TM, Dzyadevych SV, Van MC, Renault NJ, Duc CN, Chovelon JM (2004) Conductometric tyrosinase biosensor for the detection of diuron, atrazine and its main metabolites. 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Earth and Environmental Science, 924(1) , Article 012005. https://iopscience.iop.org/article/10.1088/1755-1315/924/1/012005/meta Sadullayeva GG, Rakhmatov SB (2022) Amperometric method of analysis and its advantages over other methods. Int J Res Commer it Eng social Sci 16(2):4–8. http://www.gejournal.net/index.php/IJRCIESS/article/view/244 SANTE (2021) Guidance document on analytical quality control and method validation procedures for pesticide residues analysis in food and feed. https://www.eurl-pesticides.eu/userfiles/file/EurlALL/SANTE_11312_2021.pdf . Accessed February 27, 2023 Schnell S, Maini PK (2003) A Century of Enzyme Kinetics: Reliability of the KM and vmax Estimates. Comments Theoretical Biology 8:169–187. https://ora.ox.ac.uk/objects/uuid:d75c660d-d149-4f8e-994d-bb5b5fc0cec1 /download _file?file_format = application%2Fpdf&safe_filename = 151.pdf&type_of_work = Journal + article Shou-Min FANG (2012) Insect glutathione S-transferase: a review of comparative genomic studies and response to xenobiotics. Bull Insectol 65:265–271. http://www.bulletinofinsectology.org/pdfarticles/vol65-2012-265-271fang.pdf Singh RP, Kim YJ, Oh BK, Choi JW (2009) Glutathione-s-transferase based electrochemical biosensor for the detection of captan. Electrochem Commun 11(1):181–185. https://doi.org/10.1016/j.elecom.2008.11.003 Soderlund DM (2008) Pyrethroids, knockdown resistance and sodium channels. Pest Manag Sci 64(6):610–616. https://doi.org/10.1002/ps.1574 Songa EA, Okonkwo JO (2016) Recent approaches to improving selectivity and sensitivity of enzyme-based biosensors for organophosphorus pesticides: A review. Talanta 155:289–304. https://doi.org/10.1016/j.talanta.2016.04.046 Strange RC, Spiteri MA, Ramachandran S, Fryer AA (2001) Glutathione-S-transferase family of enzymes. Mutat Research/Fundamental Mol Mech Mutagen 482(2):21–26. https://doi.org/10.1016/S0027-5107(01)00206-8 Tang W, Wu J (2014) Amperometric determination of organophosphorus pesticide by silver electrode using an acetylcholinesterase inhibition method. Anal Methods 6(3):924–929. https://doi.org/10.1039/C3AY41932K Tankiewicz M, Berg A (2022) Improvement of the QuEChERS method coupled with GC–MS/MS for the determination of pesticide residues in fresh fruit and vegetables. Microchem J 181:107794. https://dx.doi.org/10.2139/ssrn.4125938 Thakkar JB, Gupta S, Prabha CR (2019) Acetylcholine esterase enzyme doped multiwalled carbon nanotubes for the detection of organophosphorus pesticide using cyclic voltammetry. Int J Biol Macromol 137:895–903. https://doi.org/10.1016/j.ijbiomac.2019.06.162 Upadhayay J, Rana M, Juyal V, Bisht SS, Joshi R (2020) Impact of pesticide exposure and associated health effects. In: Srivastava PK, Singh VP, Singh A, Tripathi DK, Singh S, Prasad SM, Chauhan DK (eds) Pesticides in crop production: physiological and biochemical action. John Wiley & Sons Ltd, pp 69–88. https://doi.org/10.1002/9781119432241.ch5 Watanabe E, Baba K (2015) Highly sensitive quantification of pyrethroid insecticide etofenprox in vegetables with high-performance liquid chromatography and fluorescence detection. J Chromatogr A 1385:35–41. https://doi.org/10.1016/j.chroma.2015.01.056 Xie X, Zhou B, Zhang Y, Zhao G, Zhao B (2021) A multi-residue electrochemical biosensor based on graphene/chitosan/parathion for sensitive organophosphorus pesticides detection. Chem Phys Lett 767:138355. https://doi.org/10.1016/j.cplett.2021.138355 Yanuar H (2001) Kinetics of the acetylcholinesterase (ache) inhibition. Indonesian J Chem 1(3):131–137. https://doi.org/10.22146/ijc.21939 Yotova L, Medhat N (2011) Optical biosensor with multienzyme system immobilized onto hybrid membrane for pesticides determination. Int J Bioautomation 15(4):267. http://www.biomed.bas.bg/bioautomation/2011/vol_15.4/files/15.4_05.pdf Zamora S, Perez SRR, Carillo RO, Villalobos VS (2019) What are the main sensor methods for quantifying pesticides in agricultural activities? A review. Molecules 24(14):2659. https://doi.org/10.3390/molecules24142659 Additional Declarations The authors declare no competing interests. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4900144","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":339135598,"identity":"cb439e36-b376-4620-a0cb-b44c30d3fda2","order_by":0,"name":"M. M. 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1","display":"","copyAsset":false,"role":"figure","size":86715,"visible":true,"origin":"","legend":"\u003cp\u003eUV-Vis measured for the mixture of GST and GSH with CDNB\u003c/p\u003e","description":"","filename":"image1.png","url":"https://assets-eu.researchsquare.com/files/rs-4900144/v1/2d23b1af77f1b82d1b7a75c9.png"},{"id":62354989,"identity":"8058300c-6dcc-4c2c-8aef-634c2eb17298","added_by":"auto","created_at":"2024-08-13 09:00:35","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":120706,"visible":true,"origin":"","legend":"\u003cp\u003eLineweaver-Burk Plot of substrate (GSH-CDNB) and various insecticides\u003c/p\u003e","description":"","filename":"image2.png","url":"https://assets-eu.researchsquare.com/files/rs-4900144/v1/ffc4a7b61d568451a35fa453.png"},{"id":62355945,"identity":"a2bc0441-88bc-47f6-98c1-5a071eb53d54","added_by":"auto","created_at":"2024-08-13 09:08:35","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":255466,"visible":true,"origin":"","legend":"\u003cp\u003eCalibration curve of inhibition rate (%) \u003cem\u003evs.\u003c/em\u003e negative logarithm of various insecticides (-Log C) (0.01-0.5 mg kg\u003csup\u003e-1\u003c/sup\u003e) using potentiometric method\u003c/p\u003e","description":"","filename":"image3.png","url":"https://assets-eu.researchsquare.com/files/rs-4900144/v1/621435b6435e61f1822944bf.png"},{"id":62356754,"identity":"59f3db08-8b0e-4019-b54c-ff3125137277","added_by":"auto","created_at":"2024-08-13 09:16:35","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":164373,"visible":true,"origin":"","legend":"\u003cp\u003eCyclic voltammograms of GST with different substrate (GSH-CDNB) concentrations (1-7 Mm)\u003c/p\u003e","description":"","filename":"image4.png","url":"https://assets-eu.researchsquare.com/files/rs-4900144/v1/090a339a255e3f3fc5539667.png"},{"id":62355947,"identity":"9116a2b4-12f1-4858-863b-c1db499d998e","added_by":"auto","created_at":"2024-08-13 09:08:35","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":183533,"visible":true,"origin":"","legend":"\u003cp\u003eInhibition of GST with imidacloprid insecticide at different concentrations (0.01-0.5 mg kg\u003csup\u003e-1\u003c/sup\u003e)\u003c/p\u003e","description":"","filename":"image5.png","url":"https://assets-eu.researchsquare.com/files/rs-4900144/v1/cd0e14120d3ea91e943f196b.png"},{"id":62354995,"identity":"13c3e0d7-f364-4ca2-b4ce-1954557e0089","added_by":"auto","created_at":"2024-08-13 09:00:35","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":277139,"visible":true,"origin":"","legend":"\u003cp\u003eCalibration curve of inhibition rate (%) \u003cem\u003evs.\u003c/em\u003e negative logarithm of synthetic pyrethroid and neonicotinoid insecticides (-Log C) (0.01-0.5 mg kg\u003csup\u003e-1\u003c/sup\u003e) using amperometric method\u003c/p\u003e","description":"","filename":"image6.png","url":"https://assets-eu.researchsquare.com/files/rs-4900144/v1/cee0905def9edd7ff80d2268.png"},{"id":62354991,"identity":"6ae918f1-89e9-440d-a1f6-3fcf7df58076","added_by":"auto","created_at":"2024-08-13 09:00:35","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":784475,"visible":true,"origin":"","legend":"\u003cp\u003eCyclic voltammograms of GST with substrate (GSH-CDNB) and lambda cyhalothrin insecticide (0.01 mg kg\u003csup\u003e-1\u003c/sup\u003e) at different scan rate (20-100 mV/s)\u003c/p\u003e","description":"","filename":"image7.png","url":"https://assets-eu.researchsquare.com/files/rs-4900144/v1/27afd78b590ed2dd19d29618.png"},{"id":62355950,"identity":"0cccb9d0-55d6-4802-bb8a-e4398786f679","added_by":"auto","created_at":"2024-08-13 09:08:35","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":535299,"visible":true,"origin":"","legend":"\u003cp\u003eStandard chromatograms of (a) imidacloprid (0.025 mg kg-1), (b) thiamethoxam (0.025 mg kg-1), (c) acetamiprid (0.025 mg kg-1), (d) synthetic pyrethroids (0.01 mg kg-1) analysed in GC-MS/LC-MS\u003c/p\u003e","description":"","filename":"image8.png","url":"https://assets-eu.researchsquare.com/files/rs-4900144/v1/934e88af98f13fc7640d7812.png"},{"id":62354992,"identity":"9218da94-6db1-49b3-9b91-0d778c742ed8","added_by":"auto","created_at":"2024-08-13 09:00:35","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":585880,"visible":true,"origin":"","legend":"\u003cp\u003eRecovery chromatogram of (a) imidacloprid (0.025 mg kg-1), (b) thiamethoxam (0.025 mg kg-1), (c) acetamiprid (0.025 mg kg-1), (e) synthetic pyrethroid (0.01 mg kg-1) in bitter gourd fruit analysed in GC-MS/LC-MS\u003c/p\u003e","description":"","filename":"image9.png","url":"https://assets-eu.researchsquare.com/files/rs-4900144/v1/fcb61296a9d4a2d7d040c139.png"},{"id":62357341,"identity":"ee23e2d4-6ffd-43e3-a134-3ad832b47a0f","added_by":"auto","created_at":"2024-08-13 09:24:40","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":4355702,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4900144/v1/1fe9c380-7741-4f9a-82bf-bc2848efde77.pdf"},{"id":62355944,"identity":"48bef04c-acf9-49bc-bd6b-bbdbce8c721e","added_by":"auto","created_at":"2024-08-13 09:08:35","extension":"jpg","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":231506,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"graphicalabstract.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4900144/v1/544e46c8a665d580b1f33d16.jpg"},{"id":62354987,"identity":"c265bc3c-3954-4941-8c90-efd8a2ec56ad","added_by":"auto","created_at":"2024-08-13 09:00:34","extension":"doc","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":32768,"visible":true,"origin":"","legend":"","description":"","filename":"Highlights.doc","url":"https://assets-eu.researchsquare.com/files/rs-4900144/v1/5f2faebc691c58696323afd8.doc"}],"financialInterests":"The authors declare no competing interests.","formattedTitle":"\u003cp\u003e\u003cstrong\u003eDetection of multi-residue insecticides in bitter gourd using Glutathione-S-Transferase enzyme based different analytical techniques\u003c/strong\u003e\u003c/p\u003e","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eBitter gourd (\u003cem\u003eMomordica charantia\u003c/em\u003e L.) is well known and demanded vegetable among cucurbits grown in India. During 2021-22, India produced 12.96 lakh metric tonnes of bitter gourd and cultivated in 1.07 lakh hectares (Indiastat, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). The extent of losses in bitter gourd may range from 30 to 100%, depending on the pest infestation (Kumari et al., \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). Therefore, insecticides are necessary and important in modern-day agricultural practices for pest management in vegetable cultivation. However, the application of insecticides indiscriminately, especially during the fruiting stage, and failure to adopt safe waiting period result in the accumulation of pesticide residues in marketable vegetables (Rani et al., \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Upadhayay et al., \u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). Thus, detection and quantification of insecticide residues in fruits and vegetables have become essential requirement for consumers, producers and food quality control authorities. During the last two decades, synthetic pyrethroids (lambda-Cyhalothrin, Deltamethrin, Fenvalerate, etc.,) and neonicotinoid (imidacloprid, acetamiprid, thiacloprid, clothianidin etc.,) have become a predominant class of insecticides used against pests in agricultural lands, gardens, and houses, accounting for 25\u0026ndash;30% of the insecticide market, worldwide (Demeneix et al., \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Hladik et al., \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2016\u003c/span\u003e; Soderlund, \u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e2008\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eGlutathione S-Transferase (GST) is a multigenic family of cytosolic proteins involved in multiple biological roles like, biotransformation of chemicals, reducing oxidative stress and cell regulatory mechanisms in major living organisms (Strange et al., \u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e2001\u003c/span\u003e; Friedman, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2011\u003c/span\u003e). GST-mediated detoxification in insects can occur directly (phase I) or through the metabolism of secondary metabolites produced by other detoxification enzymes (phase II), (Kostaropoulos et al., \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2001\u003c/span\u003e; Shou-Min, \u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e2012\u003c/span\u003e). The primary detoxification process in insects is GST catalysed reaction of formation of thioether conjugates between insecticides compounds and endogenous tripeptide glutathione (GSH) (Enayati et al., \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2005\u003c/span\u003e; Noori et al., \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). Thus in-vitro study of the GST catalysed reaction is important not only to understand the molecular basis of insecticide resistance but also to develop protocols for detection and quantification of those pesticides and could be used in developing biosensor (Choi et al., \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2003\u003c/span\u003e; Singh et al., \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e2009\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe most popular conventional techniques such as GC, HPLC, GC-MS, LC-MS, UV-spectrophotometry and ELISA (Tankiewicz and Berg, \u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Harshit et al., \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Watanabe, \u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e2015\u003c/span\u003e) are used for detecting and quantification insecticides residue in food samples. These conventional techniques are time-consuming, labour-intensive, and need sophisticated equipment as well as proper sample preparation (Beitollahi et al., \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Xie et al., \u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Kaur and Singh, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Kalyani et al., \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). The enzyme inhibition based electrochemical biosensors are suitable approach due to their capabilities of quick detection, reliability, less expensive, no/less sample preparation and feasibility. The development of bioanalytical methods and biosensors for different classes of pesticide residues using various kinds of enzymes, including acetylcholinesterase, choline oxidase, organophosphate hydrolase and tyrosinase (Thakkar et al., \u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Yotova and Medhat, 2012; Lee et al., \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Anh et al., \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2004\u003c/span\u003e). It is challenging to develop unique enzyme or bioreceptor molecules for each class of chemicals due to the class specificity of enzyme action on the one hand and the availability of several classes of pesticides in the market on the other hand (Bucur et al., \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2018\u003c/span\u003e; Karadurmus et al., \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). A recent report revealed that the electrochemical biosensor method can be employed to evaluate the GST catalysed interaction between GSH and CDNB as well as the influence of the effect on insecticidal reaction.\u003c/p\u003e \u003cp\u003eThe present work is on the development of protocols for detection and quantification of synthetic pyrethroid (lambda cyhalothrin, deltamethrin and fenvalerate) and neonicotinoid (imidacloprid, thiamethoxam and acetamiprid) insecticides GST-based biosensor probes detection. Inhibition kinetics of the six insecticides were studied and the method has been validated through analysis of bitter gourd sample and results were compared with GC-MS/LC-MS.\u003c/p\u003e"},{"header":"2. Materials and methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1. Materials\u003c/h2\u003e \u003cp\u003eGlutathione-s-transferase (GST) (from equine liver), 1-chloro-2,4-dinitrobenzene (CDNB), reduced glutathione (GSH), bovine serum albumin (BSA), glutaraldehyde (25%), gelatin, N,N-dimethylformamide (DMF), 3-mercaptopropionic acid (3-MPA), synthetic pyrethroid (lambda-cyhalothrin, deltamethrin and fenvalerate) and neonicotinoid (Imidacloprid, acetamiprid and thiamethoxam) insecticides were purchased from Sigma Aldrich, India. LC-MS grade methanol (MeOH) (Fisher chemical, USA), disodium hydrogen phosphate (dibasic) (Na\u003csub\u003e2\u003c/sub\u003eHPO\u003csub\u003e4\u003c/sub\u003e), sodium dihydrogen phosphate (monobasic) (NaH\u003csub\u003e2\u003c/sub\u003ePO\u003csub\u003e4\u003c/sub\u003e.H\u003csub\u003e2\u003c/sub\u003eO), NaCl and ethanol were procured from Merck, India, cellulose membrane (10 \u0026micro; pore size) (Hi media) and potentiometer (Systronics \u0026micro; pH system), Glass Membrane Electrode (GME) and Ag/AgCl electrode were purchased from Systronics, India. Glassy Carbon Electrode (GCE) as working electrode, platinum wire (Pt) as counter electrode, Ag/AgCl active as reference electrode and also polishing kits were purchased from Labkarts (India). Ultrapure water (18.2 MΩ) from a lab-scale (Q3 Merck) Millipore unit was used throughout the analysis.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2. Preparation of standard solutions\u003c/h2\u003e \u003cp\u003eImidacloprid, thiamethoxam and acetamiprid stock solutions (400 mg/L) were prepared in acetonitrile (LC-MS grade) by weighing 10.17, 10.11 and 10.12 mg of analytical standards into a calibrated (Class A) volumetric flask (25 ml). Lambda cyhalothrin, deltamethrin and fenvalerate were prepared by dissolving 10.17 mg, 10.01 mg and 10.06 mg respective analyte in 25 ml acetonitrile to prepare 400 mg/L of primary stock solutions. The intermediate standards (40 mg/L) were prepared by transferring 2.5 ml from the stock solution (400 mg/L) into a 25 ml volumetric flask and the volume was made with respective solvent. Serial dilution from the intermediate standard solution was made in the range of 0.0025\u0026ndash;0.5 mg/L. Matrix match standard solutions were prepared at concentration of 0.01, 0.025, 0.05, 0.075, 0.1 and 0.25 mg/L. All standard solutions were kept in a -20 \u003csup\u003e0\u003c/sup\u003eC freezer for further use.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3. Instrumentation\u003c/h2\u003e \u003cp\u003ePotentiometric experiments were carried out on digital potentiometer connected with modified glass membrane working electrode and Ag/AgCl reference electrode. Amperometric measurement was achieved using an electrochemical workstation (BioLogic, VSP-300, France). All electrochemical protocols were performed and recorded with a computer interfaced to a BioLogic electrochemical analyser and EC-Lab (V10.44) software. In this instrument two-compartment with three-electrode system was used for the measurement. Glassy carbon electrode, platinum electrode and Ag/AgCl electrode were used as working electrode, counter electrode and reference electrode, respectively. Data obtained by Cyclic Voltammetry (CV) was analysed with the software Origin 9.5 (OriginLab Corporation), using linear models to fit data from current vs potential. Glassy carbon electrode was polished with aqueous slurry containing 0.3 mm of alumina powder before use and rinsed with deionized water followed by acetone. UV Visible spectra were recorded by using spectrophotometer (Shimadzu, Japan). The synthetic pyrethroid residues in bitter gourd was detected in GC (Shimadzu 2010) and the confirmed in GC-EI-MS (Shimadzu, QP 2010 plus). The GC-EI-MS analytical method validated with DB-1MS analytical capillary column (30 m \u0026times; 0.25 mm \u0026times; 0.25 \u0026micro;m) for residue analysis. Neonicotinoid insecticide residues were determined by validated method in Shimadzu 2020 series LC-MS (single quadrupole) containing reverse phase C18 (Shim pack- Shimadzu) column (250 mm length x 4.6 mm id, 5 \u0026micro;m particle size).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e2.4. Preparation of electrochemical biosensor\u003c/h2\u003e \u003cp\u003eThe electrode surface was modified by immersion for 60 min in 3-MPA (1.0\u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e mol L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) ethanol solution and ultrapure water was used to remove unwanted impurities. The mixture of BSA (4 mg), gelatin (10%) with glutaraldehyde (2.5%) was vortexed and GST enzyme with N, N-dimethylformamide (DMF) (1%) were added to the mixture for gelation process. Further, mixture (10 \u0026micro;l) was immobilised over cellulose membrane and placed on GCE and GME. The immobilised electrode was dried and kept at 4 \u003csup\u003e0\u003c/sup\u003eC. 'O' ring made of silicone was used for the attachment of immobilised membrane to the GME.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e2.5. Analytical procedure\u003c/h2\u003e \u003cdiv id=\"Sec8\" class=\"Section3\"\u003e \u003ch2\u003e2.5.1. Spectrophotometric measurement\u003c/h2\u003e \u003cp\u003eThe substrates CDNB and GSH conjugate in the presence of GST produce yellow-colored product (2,4-dinitrophenyl) S-glutathione, which is having absorbance at 340 nm. Presence of insecticides reduce catalytic activity of GST and substrate conjugation reaction interfering the UV absorbance. The transformation of substrate into a yellow product gets reduced in the presence of inhibitor and vice versa (Choi et al., \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2003\u003c/span\u003e). Enzyme activity was calculated using parameters like Michaelis constant (\u003cem\u003eK\u003c/em\u003e\u003csub\u003e\u003cem\u003em\u003c/em\u003e\u003c/sub\u003e) and maximum reaction velocity (\u003cem\u003eV\u003c/em\u003e\u003csub\u003e\u003cem\u003emax\u003c/em\u003e\u003c/sub\u003e) through Lineweaver-Burk (LB) plot (Schnell and Maini, \u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e2003\u003c/span\u003e; Ellman et al., \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e1961\u003c/span\u003e). \u003cem\u003eV\u003c/em\u003e\u003csub\u003e\u003cem\u003emax\u003c/em\u003e\u003c/sub\u003e is the maximum reaction rate at the state where the enzyme is fully saturated by its substrate. \u003cem\u003eK\u003c/em\u003e\u003csub\u003e\u003cem\u003em\u003c/em\u003e\u003c/sub\u003e is the concentration of substrate at half of \u003cem\u003eV\u003c/em\u003e\u003csub\u003e\u003cem\u003emax\u003c/em\u003e\u003c/sub\u003e (Yanuar, \u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e2001\u003c/span\u003e; Ismail, 2021). The \u003cem\u003eK\u003c/em\u003e\u003csub\u003e\u003cem\u003em\u003c/em\u003e\u003c/sub\u003e and \u003cem\u003eV\u003c/em\u003e\u003csub\u003e\u003cem\u003emax\u003c/em\u003e\u003c/sub\u003e are obtained from the graph of reaction rate (1/V) vs. substrate concentration (1/S).\u003c/p\u003e \u003cp\u003eEnzyme activity was analysed by the addition of 50 \u0026micro;l GST into cuvette containing mixture of 5 mM CDNB\u0026thinsp;+\u0026thinsp;5 mM GSH\u0026thinsp;+\u0026thinsp;0.1 M phosphate buffer (950 \u0026micro;l). The absorbance at a wavelength of 340 nm for 10 min at 30 sec intervals was measured in the UV- VIS spectrophotometer. The catalytic inhibition reaction was measured by adding 50 \u0026micro;l of synthetic pyrethroid and neonicotinoid standards (0.01\u0026ndash;0.5 ppm) into cuvette containing GSH mixture and the absorbance was recorded at 340 nm (Borah et al., \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2017\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section3\"\u003e \u003ch2\u003e2.5.2. Potentiometric measurement\u003c/h2\u003e \u003cp\u003eA digital potentiometer was connected with modified glass membrane working electrode and Ag/AgCl reference electrode, potential signal was measured on the digital display of the potentiometric instrument. The total volume of the working solution in the reaction cell was 5 ml containing 5 mM of GSH in phosphate buffer and 5 mM CDNB (1:1). The solution mixture was stirred to measure the initial potential. Further, insecticide standard was added into reaction cell ranging from lower (0.01 mg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) to higher concentration (0.5 mg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) and the potential was measured within 0\u0026ndash;15 min.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section3\"\u003e \u003ch2\u003e2.5.3. Amperometric measurement\u003c/h2\u003e \u003cp\u003eThe electrochemical workstation consists of glassy carbon electrode as working electrode, platinum wire counter electrode and Ag/AgCl reference electrode. Five ml of GSH and CDNB mixture (1:1) taken into reaction cell was used as analytical solution for catalytic reaction. Selected synthetic pyrethroid and neonicotinoid insecticides in different concentration of 0.01 to 0.5 mg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e were added to the test solution and measured through CV technique. CV was performed at a scan rate of 20 mV.s\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e by applying a linear potential scan between \u0026minus;\u0026thinsp;0.5 to +\u0026thinsp;1.0 mV (vs. Ag/AgCl).\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003e2.6. Analysis of selected insecticides in bitter gourd using electrochemical biosensor\u003c/h2\u003e \u003cp\u003eTen-gram of homogenised bitter gourd sample was taken in 50 ml centrifuge tube and 20 ml of acetonitrile was added. The mixture was shaken for 2 min. and 3 ml of aliquot was used for determination of residues in enzymatic biosensor. Initial current of test solution was measured using 5 mM GSH and CDNB substrate in 3 ml of acetonitrile (25%) solvent in reaction cell. Further, sample solution current was measured and per cent of inhibition was calculated using the following formula (Tang and Wu, \u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e2014\u003c/span\u003e),\u003cdiv class=\"BlockQuote\"\u003e\u003cp\u003eI\u003csub\u003e1\u003c/sub\u003e \u0026ndash; I\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003cp\u003e I (%) = \u0026times; 100\u003c/p\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003eI\u003csub\u003e1\u003c/sub\u003e\u003c/p\u003e \u003cp\u003eWhere, I (%) \u0026ndash; percentage of inhibition, I\u003csub\u003e1\u003c/sub\u003e- current values before inhibition (mV), I\u003csub\u003e2\u003c/sub\u003e- current values after inhibition (mV).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003e2.7. Chromatographic measurement\u003c/h2\u003e \u003cp\u003eThe residues of lambda cyhalothrin, deltamethrin, fenvalerate, imidacloprid, thiamethoxam, and acetamiprid residues were extracted and cleaned up from bitter gourd fruit by modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) method (Anastassiades et al., \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2003\u003c/span\u003e). Ten gram sample was taken in 50 ml polypropylene centrifuge tube along with 20 ml acetonitrile and vortexed for one min. Then four grams of anhydrous magnesium sulphate and one gram of sodium chloride were added, vortexed and centrifuged for 10 min. at 6000 rpm. After centrifugation, the upper acetonitrile layer (10 ml) was passed through anhydrous sodium sulphate (4 g) to remove any remaining moisture. A six-millilitre of supernatant was transferred into a 15 ml centrifuge tube containing PSA (150 mg), GCB (25 mg) and MgSO\u003csub\u003e4\u003c/sub\u003e (900 mg), vortexed for one min. and centrifuged at 3000 rpm for 10 min. A portion of acetonitrile (4 ml) phase was carefully pipetted out in to a clean glass tube and evaporated to near dryness using turbovap LV (35 \u003csup\u003e0\u003c/sup\u003eC) with a gentle stream of nitrogen. The residues were then redissolved in one millilitre of respective solvent, filtered through a 0.2 \u0026micro;m PTFE syringe filter (Agilent, USA). The final volume was reconstituted to about one ml using n-hexane for GC-MS analysis and methanol for LC-MS analysis.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003e2.8. Validating the method for detection of selected insecticides\u003c/h2\u003e \u003cp\u003eThe effectiveness of the analytical method for the detection of multi-residue (lambda cyhalothrin, deltamethrin, fenvalerate, imidacloprid, thiamethoxam and acetamiprid) analysis of insecticides were standardised in bitter gourd sample using electrochemical biosensor and GC-MS/LC-MS and validated through parameters such as linearity, sensitivity, recovery precision and matrix effect (SANTE, 2022).\u003c/p\u003e \u003cp\u003e \u003cem\u003eLinearity\u003c/em\u003e \u003c/p\u003e \u003cp\u003eThe standard linearity curve was obtained by analysing seven different concentrations of selected insecticides ranging from 0.005 to 0.5 mg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e in biosensor and GC-MS/LC-MS with six replications. The matrix match linearity of calibration curve was established in the range of 0.01 to 0.25 mg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e for synthetic pyrethroids and neonicotinoids. The linear relationship and coefficient of variation were calculated through response of current signal in biosensor.\u003c/p\u003e \u003cp\u003e \u003cem\u003eSensitivity\u003c/em\u003e \u003c/p\u003e \u003cp\u003eThe enzymatic biosensor was evaluated using 3 ml phosphate buffer (0.1 M) test solution with insecticide standard and replicated thrice. A calibration graph of current versus analyte concentration was constructed to establish the slope and linear range. Limit of Detection (LOD) and Limit of Quantification (LOQ) were calculated in GC-MS/LC-MS by injecting the matrix match standards of synthetic pyrethroid and neonicotinoid insecticides starting from lowest concentration level. The LOD and LOQ were calculated with the following equations,\u003c/p\u003e \u003cp\u003eLOD\u0026thinsp;=\u0026thinsp;3\u0026times; standard deviation / slope\u003c/p\u003e \u003cp\u003eLOQ\u0026thinsp;=\u0026thinsp;10 \u0026times; standard deviation / slope\u003c/p\u003e \u003cp\u003e \u003cem\u003eRecovery\u003c/em\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eElectrochemical biosensor techniques\u003c/em\u003e \u003c/p\u003e \u003cp\u003eUntreated bitter gourd samples were cut into small piece and homogenised.\u003c/p\u003e \u003cp\u003eA sample of 10 g was spiked at five different concentrations of selected insecticides with three replications. Recovery (%) was calculated by comparing the current response of the known quantity of analytes in the fortified sample and spiked matrix match sample.\u003c/p\u003e \u003cp\u003e \u003cem\u003eChromatography techniques\u003c/em\u003e \u003c/p\u003e \u003cp\u003eHomogenized untreated bitter gourd fruit samples (10g) were spiked at five different concentrations of lambda cyhalothrin, deltamethrin and fenvalerate (0.01, 0.025, 0.05, 0.075 and 0.1 mg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e), imidacloprid, thiamethoxam and acetamiprid (0.025, 0.05, 0.075,0.1 and 0.25 mg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) with six replications. Recovery (%) was calculated by comparing the peak area of the known quantity of analytes in the fortified sample (prior extraction) and spiked matrix match sample (after extraction).\u003c/p\u003e \u003cp\u003e \u003cem\u003ePrecision\u003c/em\u003e \u003c/p\u003e \u003cp\u003eThe precision of the method was evaluated by determining the Relative Standard Deviation (RSD) at each spiking level (0.01 to 0.25 mg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) of bitter gourd fruit sample.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003e2.9. Monitoring of market and farmgate samples of bitter gourd for insecticides residues\u003c/h2\u003e \u003cp\u003eTwenty samples of bitter gourd were collected from market and farmgate of Coimbatore and nearby areas. The samples were labelled, brought to laboratory, homogenised and stored at -4 \u003csup\u003e0\u003c/sup\u003eC for further analysis. The samples were analysed for the presence of synthetic pyrethroid and neonicotinoid residues using electrochemical biosensor and the results are compared to GC-MS/LC-MS.\u003c/p\u003e \u003c/div\u003e"},{"header":"3. Results and Discussions","content":"\u003cdiv id=\"Sec16\" class=\"Section2\"\u003e \u003ch2\u003e3.1. Glutathione -S- Transferase (GST) enzyme activity\u003c/h2\u003e \u003cp\u003eSpectrophotometric analysis showed significant absorbance of GSH and CDNB substrate solution at 320 nm wavelength (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Lineweaver-Burk Plot (LB) of reaction rate (1/V) vs. substrate (1/S) concentration in the presence and absence of synthetic pyrethroid and neonicotinoid are shown in Fig.\u0026nbsp;2. The results of GST inhibited by synthetic pyrethroid (lambda cyhalothrin, deltamethrin and fenvalerate) and neonicotinoid (imidacloprid, thiamethoxam and acetamiprid) insecticides are given in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. Based on the conjugation reaction of the reduced GSH and CDNB substrate, Michaelis-Menten constant (\u003cem\u003eK\u003c/em\u003e\u003csub\u003e\u003cem\u003em\u003c/em\u003e\u003c/sub\u003e) and maximum velocity (\u003cem\u003eV\u003c/em\u003e\u003csub\u003e\u003cem\u003emax\u003c/em\u003e\u003c/sub\u003e) were calculated to be 0.00154 M and 0.01329 mM/s. Kinetic reaction measured in terms of \u003cem\u003eV\u003c/em\u003e\u003csub\u003e\u003cem\u003emax\u003c/em\u003e\u003c/sub\u003e of substrate in the presence of selected insecticides at 0.01 to 0.5 mg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e were 0.01519\u0026ndash;0.05249 mM/s and the value of \u003cem\u003eK\u003c/em\u003e\u003csub\u003e\u003cem\u003em\u003c/em\u003e\u003c/sub\u003e were 0.00178\u0026ndash;0.00767 M, respectively. \u003cem\u003eK\u003c/em\u003e\u003csub\u003e\u003cem\u003em\u003c/em\u003e\u003c/sub\u003e for the immobilised GST enzyme with graphene oxide-gelatin matrix was 0.083 mmol L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. The slope (1/\u003cem\u003eV\u003c/em\u003e\u003csub\u003e\u003cem\u003emax\u003c/em\u003e\u003c/sub\u003e) vs. substrate concentration provided a linear curve with \u003cem\u003eK\u003c/em\u003ei values of 219.29 mM for chlorpyriphos, 54.82 mM for ethion and 21.27 mM for DDT (Borah et al., \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2018\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eKinetic parameters of GST in presence and absence of inhibitors\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eS.No.\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eInsecticides\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eR\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003eK\u003c/em\u003e\u003csub\u003e\u003cem\u003em\u003c/em\u003e\u003c/sub\u003e (M)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003eV\u003c/em\u003e\u003csub\u003e\u003cem\u003emax\u003c/em\u003e\u003c/sub\u003e (mM/s)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSubstrate (GSH\u0026thinsp;+\u0026thinsp;CDNB)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.99\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.00154\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.01329\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLambda cyhalothrin\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.98\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.00329\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.03629\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDeltamethrin\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.98\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.00636\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.03635\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e4.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eFenvalerate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.99\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.00767\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.05249\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e5.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eImidacloprid\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.99\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.00178\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.03109\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e6.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eThiamethoxam\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.99\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.00194\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.01519\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e7.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAcetamiprid\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.98\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.00509\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.01797\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003e\u003cem\u003eKm\u003c/em\u003e-Michaelis-Menten, \u003cem\u003eVmax\u003c/em\u003e-maximum velocity, R\u003csup\u003e2\u003c/sup\u003e- Correlation coefficient\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eThe results indicated that \u003cem\u003eK\u003c/em\u003e\u003csub\u003e\u003cem\u003em\u003c/em\u003e\u003c/sub\u003e and \u003cem\u003eV\u003c/em\u003e\u003csub\u003e\u003cem\u003emax\u003c/em\u003e\u003c/sub\u003e value of enzyme-insecticide-substrate complex were higher than enzyme-substrate complex. Therefore, obtained results showed higher affinity of inhibitors to the GST enzymes. In the present study, the curve on the plot intersected in the second quadrant, is a characteristic behaviour of fully mixed inhibition (Ribeiro et al., \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Albuquerque and Ferreira, \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2007\u003c/span\u003e; Hofer and Fringeli, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e1981\u003c/span\u003e). This type of inhibition occurs when the inhibitor is capable of binding to both free enzyme and to the enzyme-substrate complex.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eFigure\u0026nbsp;2.\u003c/b\u003e Lineweaver-Burk Plot of substrate (GSH-CDNB) and various insecticides\u003c/p\u003e \u003cdiv id=\"Sec17\" class=\"Section3\"\u003e \u003ch2\u003e3.1.1. Optimization of the measurement conditions\u003c/h2\u003e \u003cp\u003eThe insecticide detection based on measurement of GST dependent on the enzyme catalytic reaction. The amount of enzyme and its substrate are crucial for enzymatic reaction and are to be optimised for measurement of insecticide residues. LB plot showed the good relationship between enzyme and substrate with good linearity (\u0026gt;\u0026thinsp;0.98) in the range of 0.01 to 0.5 mg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e at 2 U of GST enzyme. A rise of absorbance was observed when the concentration of substrate increased from 1 to 7 mM. For the detection of insecticide residues, 2 U enzyme with 5 mM GSH-CDNB level was optimised.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec18\" class=\"Section2\"\u003e \u003ch2\u003e3.2. Method validation of developed biosensor for detection of selected insecticides\u003c/h2\u003e \u003cp\u003eThe effectiveness of the analytical method used for synthetic pyrethroid (lambda cyhalothrin, deltamethrin and fenvalerate) and neonicotinoid (imidacloprid, thiamethoxam and acetamiprid) insecticide residue analysis was standardized for bitter gourd matrix. The results of method validation parameters such as linearity, sensitivity, recovery and precision are discussed below.\u003c/p\u003e \u003cdiv id=\"Sec19\" class=\"Section3\"\u003e \u003ch2\u003e3.2.1. Potentiometric measurement\u003c/h2\u003e \u003cp\u003ePotentiometric instrument measures the potential differences caused by ions in an electrochemical reaction that correlates with the concentration of analyte (Renault, \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2001\u003c/span\u003e; Rostiyanti and Mubarok, \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). The correlation coefficient (R\u003csup\u003e2\u003c/sup\u003e) value was above 0.98 for the linearity standard of synthetic pyrethroid and neonicotinoid insecticides in the concentration ranging from 0.01 and 0.5 mg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e and RSD was less than 11 per cent (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). LOD and LOQ were 0.01 and 0.05 mg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e respectively. The LOQ of the biosensor was calculated based on enzyme inhibition rate which ranged from 16.22 to 30.05 per cent (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). The mean per cent recovery of selected insecticides in bitter gourd fruits were in the range of 75.85 to 98.72 with RSD less than 4.0 per cent at concentration 0.01\u0026ndash;0.5 mg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). The linearity and recovery experiments showed inhibition percentages ranging from 3.19 to 65.10 (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e3\u003c/span\u003e). The results demonstrate that the inhibition ability of fenvalerate was the strongest and that of lambda cyhalothrin was the weakest among the selected insecticides.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eAnalytical data of synthetic pyrethroid and neonicotinoid insecticides by potentiometric method\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"8\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eParameters\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSubstrate (GSH\u0026thinsp;+\u0026thinsp;CDNB)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eLambda cyhalothrin\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eDeltamethrin\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eFenvalerate\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eImidacloprid\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eThiamethoxam\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003eAcetamiprid\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eResponse time (min)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLinearity range\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1\u0026ndash;7 mM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.01\u0026ndash;0.5 ppm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.01\u0026ndash;0.5 ppm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.01\u0026ndash;0.5 ppm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.01\u0026ndash;0.5 ppm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.01\u0026ndash;0.5 ppm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.01\u0026ndash;0.5 ppm\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRegression line\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ey\u0026thinsp;=\u0026thinsp;7.6429x\u0026thinsp;+\u0026thinsp;4.2857\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ey\u0026thinsp;=\u0026thinsp;8.5305x\u0026thinsp;+\u0026thinsp;4.9062\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ey\u0026thinsp;=\u0026thinsp;34.211x\u0026thinsp;+\u0026thinsp;0.5246\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003ey\u0026thinsp;=\u0026thinsp;7.8773x\u0026thinsp;+\u0026thinsp;0.6463\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003ey\u0026thinsp;=\u0026thinsp;10.405x\u0026thinsp;+\u0026thinsp;0.0678\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003ey\u0026thinsp;=\u0026thinsp;5.5046x\u0026thinsp;+\u0026thinsp;1.906\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003ey\u0026thinsp;=\u0026thinsp;16.581x \u0026minus;\u0026thinsp;3.5004\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCorrelation coefficient\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.998\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.981\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.984\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.983\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.985\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.991\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.993\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLOD (ppm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.01\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLOQ (ppm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRSD (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.24\u0026ndash;5.55\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.19\u0026ndash;6.94\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.60\u0026ndash;6.87\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.63\u0026ndash;7.22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.58\u0026ndash;5.23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.61\u0026ndash;9.31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.59\u0026ndash;10.52\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"8\"\u003eGSH- reduced glutathione, CDNB-1-chloro-2,4-dinitrobenzene, LOD- Limit of Detection, LOQ-Limit of Quantification,\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"8\"\u003eRSD- Relative Standard Deviation\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003ePercentage inhibition of GST for selected insecticides in potentiometric method\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"7\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eConcentration (mg/kg)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLambda cyhalothrin\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eDeltamethrin\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eFenvalerate\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eImidacloprid\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eThiamethoxam\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eAcetamiprid\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e4.58\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e10.40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e14.12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e3.08\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e5.23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e3.19\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.025\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e10.99\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e16.66\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e22.72\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e10.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e12.45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e10.99\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e16.55\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e29.04\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e30.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e16.22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e20.27\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e17.23\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.075\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e22.96\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e32.59\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e38.13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e24.81\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e28.88\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e26.64\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e30.74\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e40.34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e46.28\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e31.09\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e32.85\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e32.85\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e37.26\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e49.08\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e55.35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e38.72\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e40.14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e40.84\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e45.68\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e56.47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e65.10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e46.40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e48.56\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e48.20\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eRecovery percentage of synthetic pyrethroid and neonicotinoid insecticides in bitter gourd by potentiometric method\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c3\" namest=\"c1\"\u003e \u003cp\u003eSynthetic pyrethroid\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c6\" namest=\"c4\"\u003e \u003cp\u003eNeonicotinoid\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInsecticide/ Spiked concentration\u003c/p\u003e \u003cp\u003e(mg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMean recovery\u003c/p\u003e \u003cp\u003e(%)\u0026thinsp;\u0026plusmn;\u0026thinsp;SD\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRSD (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eInsecticide/ Spiked concentration\u003c/p\u003e \u003cp\u003e(mg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMean recovery\u003c/p\u003e \u003cp\u003e(%)\u0026thinsp;\u0026plusmn;\u0026thinsp;SD\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eRSD (%)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLambda cyhalothrin\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eImidacloprid\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e95.22\u0026thinsp;\u0026plusmn;\u0026thinsp;2.43\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2.56\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e94.46\u0026thinsp;\u0026plusmn;\u0026thinsp;1.83\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e1.94\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.075\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e98.72\u0026thinsp;\u0026plusmn;\u0026thinsp;1.43\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.075\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e88.19\u0026thinsp;\u0026plusmn;\u0026thinsp;2.89\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e3.27\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e85.15\u0026thinsp;\u0026plusmn;\u0026thinsp;0.97\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e95.07\u0026thinsp;\u0026plusmn;\u0026thinsp;3.71\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e3.90\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e76.53\u0026thinsp;\u0026plusmn;\u0026thinsp;0.85\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e98.65\u0026thinsp;\u0026plusmn;\u0026thinsp;1.08\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e1.08\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e83.31\u0026thinsp;\u0026plusmn;\u0026thinsp;2.84\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e3.41\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e79.26\u0026thinsp;\u0026plusmn;\u0026thinsp;0.83\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e1.04\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDeltamethrin\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eThiamethoxam\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e91.55\u0026thinsp;\u0026plusmn;\u0026thinsp;0.78\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.85\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e76.47\u0026thinsp;\u0026plusmn;\u0026thinsp;1.48\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e1.94\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.075\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e93.05\u0026thinsp;\u0026plusmn;\u0026thinsp;0.65\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.69\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.075\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e84.07\u0026thinsp;\u0026plusmn;\u0026thinsp;2.29\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e2.72\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e96.38\u0026thinsp;\u0026plusmn;\u0026thinsp;2.08\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2.16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e75.49\u0026thinsp;\u0026plusmn;\u0026thinsp;2.21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e2.93\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e87.67\u0026thinsp;\u0026plusmn;\u0026thinsp;2.38\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2.71\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e91.75\u0026thinsp;\u0026plusmn;\u0026thinsp;3.17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e3.46\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e92.00\u0026thinsp;\u0026plusmn;\u0026thinsp;2.21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2.40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e98.38\u0026thinsp;\u0026plusmn;\u0026thinsp;1.03\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e1.04\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFenvalerate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eAcetamiprid\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e81.85\u0026thinsp;\u0026plusmn;\u0026thinsp;0.88\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.08\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e94.81\u0026thinsp;\u0026plusmn;\u0026thinsp;1.59\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e1.68\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.075\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e78.81\u0026thinsp;\u0026plusmn;\u0026thinsp;2.79\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e3.54\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.075\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e81.47\u0026thinsp;\u0026plusmn;\u0026thinsp;1.70\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e2.09\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e82.28\u0026thinsp;\u0026plusmn;\u0026thinsp;2.18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2.65\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e82.97\u0026thinsp;\u0026plusmn;\u0026thinsp;2.81\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e3.39\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e82.56\u0026thinsp;\u0026plusmn;\u0026thinsp;1.51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.82\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e87.89\u0026thinsp;\u0026plusmn;\u0026thinsp;3.02\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e3.45\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e95.74\u0026thinsp;\u0026plusmn;\u0026thinsp;1.94\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2.03\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e93.98\u0026thinsp;\u0026plusmn;\u0026thinsp;2.26\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e2.41\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"6\"\u003e*Mean of three replications, SD- Standard Deviation, RSD- Relative Standard Deviation\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec20\" class=\"Section3\"\u003e \u003ch2\u003e3.2.2. Amperometric measurement\u003c/h2\u003e \u003cp\u003eAmperometric biosensors generally measure the variations in current based on electroactive chemical reaction between the recognition component and the analyte (Sadullayeva and Rakhmatov, \u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). Cyclic Voltammetry (CV) was carried out from \u0026minus;\u0026thinsp;0.5 to +\u0026thinsp;1 mV with scan rate of 20 mV/s in phosphate buffer solution at pH 7.0. The sharpness of peaks in CV indicated the well binding of enzyme layer onto the GCE surface (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe Cyclic Voltammetry (CV) responses of different concentration of substrate (GST-CDNB) in potential window range of -0.5 to +\u0026thinsp;1 mV, recorded at a scan rate of 20 mV/s are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e4\u003c/span\u003e. The linearity of the calibration curves for substrate (GST-CDNB) was established with seven levels of concentration (1\u0026ndash;7 mM) having significant R\u003csup\u003e2\u003c/sup\u003e value (0.99) and satisfactory RSD (0.75\u0026ndash;2.60%) (Table\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e). The R\u003csup\u003e2\u003c/sup\u003e value of more than 0.98 and RSD less than 10 per cent were obtained when the linearity range of selected insecticides were 0.01 to 0.5 mg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. The LOD and LOQ for synthetic pyrethroid and neonicotinoid insecticides were 0.01 and 0.5 mg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, respectively. The LOQ of the biosensor was calculated based on enzyme inhibition rate, which ranged from 22.24 to 32.00 per cent (Table\u0026nbsp;\u003cspan refid=\"Tab6\" class=\"InternalRef\"\u003e6\u003c/span\u003e). The mean per cent recovery of selected insecticides in bitter gourd fruits ranged from 71.44 to 99.04 with RSD less than 6.0 per cent at the concentration 0.01\u0026ndash;0.5 mg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e (Table\u0026nbsp;\u003cspan refid=\"Tab7\" class=\"InternalRef\"\u003e7\u003c/span\u003e). The inhibition percentages ranged from 6.04 to 59.75 in linearity and recovery experiments (Figs.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e5\u003c/span\u003e \u0026amp; \u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e6\u003c/span\u003e). These results indicated a good performance for determination of selected insecticides in bitter gourd samples. Borah et al. (\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2017\u003c/span\u003e) determined the LOD of insecticides temephos, dimethoate and fenbucarb using GST immobilised glassy carbon electrode as 0.002, 0.004 and 0.005 ppm respectively and R\u003csup\u003e2\u003c/sup\u003e of 0.99 for the linear range of 2\u0026ndash;50 ppb.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eAnalytical data of synthetic pyrethroid and neonicotinoid insecticides by amperometric method\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"8\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eParameters\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSubstrate (GSH\u0026thinsp;+\u0026thinsp;CDNB)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eLambda cyhalothrin\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eDeltamethrin\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eFenvalerate\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eImidacloprid\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eThiamethoxam\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003eAcetamiprid\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eResponse time (min)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLinearity range\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1\u0026ndash;7 mM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.01\u0026ndash;0.5 ppm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.01\u0026ndash;0.5 ppm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.01\u0026ndash;0.5 ppm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.01\u0026ndash;0.5 ppm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.01\u0026ndash;0.5 ppm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.01\u0026ndash;0.5 ppm\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRegression line\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ey\u0026thinsp;=\u0026thinsp;7.9746x\u0026thinsp;+\u0026thinsp;12.756\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ey\u0026thinsp;=\u0026thinsp;14.619x\u0026thinsp;+\u0026thinsp;40.23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ey\u0026thinsp;=\u0026thinsp;6.6775x\u0026thinsp;+\u0026thinsp;16.786\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003ey\u0026thinsp;=\u0026thinsp;6.3759x\u0026thinsp;+\u0026thinsp;23.403\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003ey\u0026thinsp;=\u0026thinsp;2.8371x\u0026thinsp;+\u0026thinsp;15.401\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003ey\u0026thinsp;=\u0026thinsp;2.2111x\u0026thinsp;+\u0026thinsp;16.458\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003ey\u0026thinsp;=\u0026thinsp;8.6593x\u0026thinsp;+\u0026thinsp;13.164\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCorrelation coefficient\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.996\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.982\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.981\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.989\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.992\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.986\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.986\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLOD (ppm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.01\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLOQ (ppm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRSD (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.75\u0026ndash;2.60\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.63\u0026ndash;9.79\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.75\u0026ndash;9.18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.89\u0026ndash;7.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.98\u0026ndash;6.39\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e1.66\u0026ndash;9.45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e1.14\u0026ndash;5.69\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"8\"\u003eGSH- reduced glutathione, CDNB-1-chloro-2,4-dinitrobenzene, LOD- Limit of Detection, LOQ-Limit of Quantification,\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"8\"\u003eRSD- Relative Standard Deviation\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab6\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 6\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eThe percentage of inhibition of GST for selected insecticides in amperometric method\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"7\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eConcentration (mg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLambda cyhalothrin\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eDeltamethrin\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eFenvalerate\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eImidacloprid\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eThiamethoxam\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eAcetamiprid\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e9.07\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e10.13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e9.26\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e10.94\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e9.94\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e6.04\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.025\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17.92\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e18.89\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e18.67\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15.65\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e17.03\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e19.25\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e25.63\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e29.04\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e27.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e22.24\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e23.87\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e32.00\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.075\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e30.73\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e37.48\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e31.79\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e29.72\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e30.76\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e37.16\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e34.53\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e40.62\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e32.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e32.88\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e32.45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e40.27\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e40.62\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e51.61\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e40.82\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e40.49\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e38.51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e52.01\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e47.47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e59.75\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e50.08\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e48.31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e43.47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e59.28\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab7\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 7\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eRecovery percentage of synthetic pyrethroid and neonicotinoid insecticides in bitter gourd by amperometric method\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c3\" namest=\"c1\"\u003e \u003cp\u003eSynthetic pyrethroid\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c6\" namest=\"c4\"\u003e \u003cp\u003eNeonicotinoid\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInsecticide/ Spiked concentration\u003c/p\u003e \u003cp\u003e(mg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMean recovery\u003c/p\u003e \u003cp\u003e(%)\u0026thinsp;\u0026plusmn;\u0026thinsp;SD\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRSD (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eInsecticide/ Spiked concentration\u003c/p\u003e \u003cp\u003e(mg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMean recovery\u003c/p\u003e \u003cp\u003e(%)\u0026thinsp;\u0026plusmn;\u0026thinsp;SD\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eRSD (%)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLambda cyhalothrin\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eImidacloprid\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e92.73\u0026thinsp;\u0026plusmn;\u0026thinsp;0.96\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.03\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e92.93\u0026thinsp;\u0026plusmn;\u0026thinsp;3.68\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e3.96\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.075\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e94.85\u0026thinsp;\u0026plusmn;\u0026thinsp;1.27\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.075\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e78.23\u0026thinsp;\u0026plusmn;\u0026thinsp;1.28\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e1.64\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e92.85\u0026thinsp;\u0026plusmn;\u0026thinsp;2.58\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2.78\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e99.04\u0026thinsp;\u0026plusmn;\u0026thinsp;2.23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e2.25\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e81.63\u0026thinsp;\u0026plusmn;\u0026thinsp;3.75\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e4.59\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e81.37\u0026thinsp;\u0026plusmn;\u0026thinsp;2.96\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e3.63\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e85.15\u0026thinsp;\u0026plusmn;\u0026thinsp;2.97\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e3.49\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e77.74\u0026thinsp;\u0026plusmn;\u0026thinsp;2.86\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e3.68\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDeltamethrin\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eThiamethoxam\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e93.51\u0026thinsp;\u0026plusmn;\u0026thinsp;3.29\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e3.52\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e80.59\u0026thinsp;\u0026plusmn;\u0026thinsp;2.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e2.48\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.075\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e77.33\u0026thinsp;\u0026plusmn;\u0026thinsp;1.93\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2.47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.075\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e78.24\u0026thinsp;\u0026plusmn;\u0026thinsp;3.83\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e4.89\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e77.23\u0026thinsp;\u0026plusmn;\u0026thinsp;1.14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.48\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e81.63\u0026thinsp;\u0026plusmn;\u0026thinsp;1.99\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e2.44\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e76.15\u0026thinsp;\u0026plusmn;\u0026thinsp;4.35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e5.72\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e87.99\u0026thinsp;\u0026plusmn;\u0026thinsp;1.67\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e1.90\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e71.44\u0026thinsp;\u0026plusmn;\u0026thinsp;1.21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.69\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e81.92\u0026thinsp;\u0026plusmn;\u0026thinsp;3.52\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e4.29\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFenvalerate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eAcetamiprid\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e75.13\u0026thinsp;\u0026plusmn;\u0026thinsp;1.88\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2.51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e77.89\u0026thinsp;\u0026plusmn;\u0026thinsp;3.03\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e3.89\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.075\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e73.76\u0026thinsp;\u0026plusmn;\u0026thinsp;3.54\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e4.79\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.075\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e97.75\u0026thinsp;\u0026plusmn;\u0026thinsp;1.85\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e1.89\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e84.41\u0026thinsp;\u0026plusmn;\u0026thinsp;2.47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2.92\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e94.40\u0026thinsp;\u0026plusmn;\u0026thinsp;1.29\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e1.36\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e86.48\u0026thinsp;\u0026plusmn;\u0026thinsp;4.77\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e5.51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e96.09\u0026thinsp;\u0026plusmn;\u0026thinsp;3.29\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e3.43\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e81.71\u0026thinsp;\u0026plusmn;\u0026thinsp;3.03\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e3.71\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e80.12\u0026thinsp;\u0026plusmn;\u0026thinsp;0.77\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.96\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"6\"\u003e*Mean of three replications, SD- Standard Deviation, RSD- Relative Standard Deviation\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe CV results of GST reaction as depicted in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e4\u003c/span\u003e showed strong oxidation peak with addition of the substrate (GSH\u0026thinsp;+\u0026thinsp;CDNB) and the magnitude of the anodic current\u003c/p\u003e \u003cp\u003e(\u003cem\u003eE\u003c/em\u003ep\u0026thinsp;=\u0026thinsp;+\u0026thinsp;75 \u0026micro;A (vs. Ag/AgCl)) was higher than in the absence of substrate (\u003cem\u003eE\u003c/em\u003ep\u0026thinsp;=\u0026thinsp;+\u0026thinsp;8 \u0026micro;A). The CV results are depicted in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e5\u003c/span\u003e, the prominent redox peaks were observed for the biosensor before inhibition. After inhibition by selected insecticides relative decrease in anodic current was observed (5\u0026ndash;40 \u0026micro;A) and peak potential range of +\u0026thinsp;600 and +\u0026thinsp;850 mV (vs. Ag/AgCl) was obtained. The peak currents of electrochemical reaction were indirectly proportional to the insecticide concentration and further an increase in the insecticide concentration leads to decrease in the peak current. The observed CV behaviour of GST enzyme with substrate (GSH\u0026thinsp;+\u0026thinsp;CDNB) could be explained with the following reaction mechanism. Enzyme-substrate complex in organic solvent dissociates into COH and CO\u003csup\u003e\u0026minus;\u003c/sup\u003e ions. The CO\u003csup\u003e\u0026minus;\u003c/sup\u003e thus produced interacts with GSH to produce electro active intermediate. Under electrochemical process in which CO\u003csup\u003e\u0026minus;\u003c/sup\u003e formed from oxidation at higher potential (0.90 V) triggers the reaction of GSH (Borah et al., \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2016\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec21\" class=\"Section3\"\u003e \u003ch2\u003e3.2.3. Optimization of experimental parameters\u003c/h2\u003e \u003cp\u003eIn the electrochemical study, enzyme was immobilised in cellulose membrane connected to glass membrane and glassy carbon electrode integrated with transducer signal of potentiometer and potentiostat/ galvanostat. Working of biosensor is highly influenced by the type and thickness of membrane as they are the supporting material for working electrode of biosensor (Reybier et al., \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e2002\u003c/span\u003e; Bucur et al., \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). The most important step in the development of an enzyme biosensor is the stable attachment of enzyme to the surface of working electrode. It was governed by various interactions between enzyme and electrode surface for improved response, stability and reproducibility (Ivanov et al., \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Rodrigues et al., \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). According to research, GST enzyme based biosensor designed for detection of selected insecticides works in the range of 600\u0026ndash;850 mV. This over potential may affect the activity of enzyme resulting in poor biosensing performance and instability of the biosensor. Moreover, high working potential can cause oxidation of other species present in the media (Raghu et al., \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e2014\u003c/span\u003e). Thus, possible lower potentials are preferred in amperometric systems. To overcome the problem, immobilization materials could be achieved using electrochemical mediators onto the transducers. In this system, combination of different techniques such as cross-linking, entrapment, covalent binding and adsorption are used.\u003c/p\u003e \u003cp\u003eThe cellulose membrane was used as the supporting material for glass membrane and glassy carbon electrode and immobilization of enzyme GST by the process of cross-linking, entrapment and adsorption using Bovine Serum Albumin (BSA) (4 mg), glutaraldehyde (2.5%) and gelatin (10%). The combination-based GST immobilisation was reported to be more effective than one based glutaraldehyde or BSA alone (Pohanka and Skladal, \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e2008\u003c/span\u003e; Rekha and Murthy, \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2008\u003c/span\u003e). The interaction energy that occurs between enzyme-substrate-inhibitor increases the conductive area and electron-transfer rate between the electrode surface and analyte. Linearity between the reaction of the enzyme modified electrode and the anodic peak current of oxidation was good, which resulted due to a controlled diffusion process (Mashuni et al., \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Kesik et al., \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2014\u003c/span\u003e). These findings support high electrooxidation ability of the enzyme-modified electrode towards insecticides, which showed synchronised electrochemical response.\u003c/p\u003e \u003cp\u003eThe developed biosensor was tested at different working potentials for the 2.0 U GST with 5 mM of substrate to investigate optimum working potential. As illustrated in Fig. \u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e7\u003c/span\u003e, the amperometric response was recorded at different scan rates (20-100 mV/s) applied potential versus Ag/AgCl wire reference electrode. It can be seen that the potential response increases with scan rate increasing within 20-100 mV. Optimum inhibition rate was obtained with the scan rate of 20 mV/s for all insecticides. To examine the relationship between amount of enzyme and biosensor response, biosensors was prepared with different GST concentration between 0.5 U and 2.0 U where other components were kept constant. As seen in Fig. \u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e4\u003c/span\u003e, the highest signal was recorded with 2.0 U GST. In case of excess loading of enzyme, the enzyme molecules leached from the surface since adsorbed enzyme was not sufficiently stable on the limited electrode area (Cesarino et al., 2014). On the other hand, if substantial amount of biomolecule could not be immobilized onto the electrode, biosensor responses decreased due to inadequate enzymatic reaction which leads to low sensitivity (Songa and Okonkwo, \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e2016\u003c/span\u003e). Sufficient working stability and reasonable signals were achieved with 2 U GST.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eLow pesticide concentrations could not be detected and the response decreased at low substrate concentrations. The percentage of inhibition was evaluated from the response of the active and inhibited forms of the enzyme. Therefore, all the enzyme molecules in the medium have to take part in the reaction and this could only be possible in substrate concentrations corresponding to the saturation portion of the activity versus substrate (GSH) curves. High substrate concentrations (5 mM) were then selected for use in further studies, namely for entrapped 2 U GST immobilized enzymes (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e4\u003c/span\u003e). Under such conditions, the inhibition mechanism is mixed inhibition, so that the substrate would compete/non-compete with the analyte for the enzyme active site and inhibition, especially at low analyte concentrations could be detected.\u003c/p\u003e \u003cp\u003eInsecticide concentrations ranging from 0.01 to 0.5 ppm were tested in terms of their effect on enzyme activity at different incubation times in pesticide solution (5, 10, 15 and 20 min). It can be seen that (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e5\u003c/span\u003e) level of inhibition of the enzyme increased with increasing incubation period until reaching a plateau level. The GST immobilized enzyme system responds to the presence of the insecticide more quickly than the entrapped form. The decrease in activity was less pronounced beyond 10 min for both systems and therefore, the incubation time was selected as 10 min.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec22\" class=\"Section2\"\u003e \u003ch2\u003e3.3. Validation of multi-residue analysed method using GC-MS/LC-MS\u003c/h2\u003e \u003cp\u003eThe effectiveness of the analytical method used for multi-residue insecticide analysis was standardized for bitter gourd matrix as per SANTE guidelines (SANTE, \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). Excellent linear relationships and correlation coefficients (R\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.99) for lambda cyhalothrin, deltamethrin, fenvalerate, imidacloprid, thiamethoxam and acetamiprid in solvent and matrix match standard were observed (Table\u0026nbsp;\u003cspan refid=\"Tab8\" class=\"InternalRef\"\u003e8\u003c/span\u003e and Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e8\u003c/span\u003e). The LOD and LOQ for synthetic pyrethroid were 0.0025 and 0.01 mg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e and 0.0075 and 0.025 mg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e for neonicotinoids, respectively. Recovery ranged between 76.70-104.20 per cent, with an RSD less than seven per cent (Table\u0026nbsp;\u003cspan refid=\"Tab9\" class=\"InternalRef\"\u003e9\u003c/span\u003e and Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e9\u003c/span\u003e). The matrix effect was within 0.68\u0026ndash;10.26 per cent of the spiked standards (Table\u0026nbsp;\u003cspan refid=\"Tab8\" class=\"InternalRef\"\u003e8\u003c/span\u003e). Matrix effect values were less than 11 per cent in both matrices, indicating that the samples had no apparent matrix effect and that the cleanup effect was adequate. These results suggested that the method provided repeatable and reliable results with acceptable recovery.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab8\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 8\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eLinearity parameters and matrix effect for selected insecticides in bitter gourd\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInsecticides\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCalibration (matrix)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eCalibration range (mg/L)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eRegression equation\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eCorrelation \u003c/p\u003e \u003cp\u003ecoefficient (R\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eMatrix \u003c/p\u003e \u003cp\u003eeffect (%)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLambda cyhalothrin\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSolvent\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.0025-0.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ey\u0026thinsp;=\u0026thinsp;7E\u0026thinsp;+\u0026thinsp;06x\u0026thinsp;+\u0026thinsp;67004\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.993\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eFruit\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.01\u0026ndash;0.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ey\u0026thinsp;=\u0026thinsp;125677x \u0026minus;\u0026thinsp;121395\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.991\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.68\u0026ndash;6.69\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDeltamethrin\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSolvent\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.0025-0.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ey\u0026thinsp;=\u0026thinsp;5E\u0026thinsp;+\u0026thinsp;06x\u0026thinsp;+\u0026thinsp;35242\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.997\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eFruit\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.01\u0026ndash;0.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ey\u0026thinsp;=\u0026thinsp;101004x \u0026minus;\u0026thinsp;83609\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.993\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.11\u0026ndash;3.92\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFenvalerate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSolvent\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.0025-0.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ey\u0026thinsp;=\u0026thinsp;6E\u0026thinsp;+\u0026thinsp;06x\u0026thinsp;+\u0026thinsp;11374\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.997\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eFruit\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.01\u0026ndash;0.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ey\u0026thinsp;=\u0026thinsp;112784x \u0026minus;\u0026thinsp;112367\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.985\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.83\u0026ndash;3.41\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eImidacloprid\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSolvent\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.005\u0026ndash;0.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ey\u0026thinsp;=\u0026thinsp;2E\u0026thinsp;+\u0026thinsp;06x\u0026thinsp;+\u0026thinsp;25602\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.997\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eFruit\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.025\u0026ndash;0.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ey\u0026thinsp;=\u0026thinsp;1E\u0026thinsp;+\u0026thinsp;06x \u0026minus;\u0026thinsp;4682.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.997\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.10\u0026ndash;5.62\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAcetamiprid\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSolvent\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.005\u0026ndash;0.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ey\u0026thinsp;=\u0026thinsp;8E\u0026thinsp;+\u0026thinsp;06x\u0026thinsp;+\u0026thinsp;81868\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.994\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eFruit\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.025\u0026ndash;0.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ey\u0026thinsp;=\u0026thinsp;2E\u0026thinsp;+\u0026thinsp;06x \u0026minus;\u0026thinsp;6549.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.997\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.89\u0026ndash;8.97\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eThiamethoxam\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSolvent\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.005\u0026ndash;0.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ey\u0026thinsp;=\u0026thinsp;912330x\u0026thinsp;+\u0026thinsp;13711\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.995\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eFruit\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.025\u0026ndash;0.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ey\u0026thinsp;=\u0026thinsp;1E\u0026thinsp;+\u0026thinsp;06x\u0026thinsp;+\u0026thinsp;6632.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.995\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.91\u0026ndash;10.26\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab9\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 9\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eRecovery percentage of synthetic pyrethroid and neonicotinoid insecticides in bitter gourd by GC-MS/LC-MS\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c3\" namest=\"c1\"\u003e \u003cp\u003eSynthetic pyrethroid\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c6\" namest=\"c4\"\u003e \u003cp\u003eNeonicotinoid\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInsecticide/ Spiked concentration\u003c/p\u003e \u003cp\u003e(mg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMean recovery\u003c/p\u003e \u003cp\u003e(%)\u0026thinsp;\u0026plusmn;\u0026thinsp;SD\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRSD (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eInsecticide/ Spiked concentration\u003c/p\u003e \u003cp\u003e(mg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMean recovery\u003c/p\u003e \u003cp\u003e(%)\u0026thinsp;\u0026plusmn;\u0026thinsp;SD\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eRSD (%)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLambda cyhalothrin\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eImidacloprid\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e88.34\u0026thinsp;\u0026plusmn;\u0026thinsp;1.71\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.93\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e95.86\u0026thinsp;\u0026plusmn;\u0026thinsp;2.71\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e2.82\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.075\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e83.57\u0026thinsp;\u0026plusmn;\u0026thinsp;2.02\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2.43\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.075\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e99.90\u0026thinsp;\u0026plusmn;\u0026thinsp;2.51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e2.51\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e95.98\u0026thinsp;\u0026plusmn;\u0026thinsp;1.03\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.07\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e99.93\u0026thinsp;\u0026plusmn;\u0026thinsp;2.52\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e2.52\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e82.09\u0026thinsp;\u0026plusmn;\u0026thinsp;5.43\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e6.62\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e95.83\u0026thinsp;\u0026plusmn;\u0026thinsp;4.18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e4.36\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e80.93\u0026thinsp;\u0026plusmn;\u0026thinsp;3.87\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e4.79\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e101.32\u0026thinsp;\u0026plusmn;\u0026thinsp;2.62\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e2.59\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDeltamethrin\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eThiamethoxam\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e84.15\u0026thinsp;\u0026plusmn;\u0026thinsp;1.97\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2.34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e98.65\u0026thinsp;\u0026plusmn;\u0026thinsp;2.29\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e2.32\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.075\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e84.48\u0026thinsp;\u0026plusmn;\u0026thinsp;1.89\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2.23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.075\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e102.89\u0026thinsp;\u0026plusmn;\u0026thinsp;2.53\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e2.46\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e83.61\u0026thinsp;\u0026plusmn;\u0026thinsp;2.46\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2.94\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e97.58\u0026thinsp;\u0026plusmn;\u0026thinsp;4.21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e4.27\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e85.42\u0026thinsp;\u0026plusmn;\u0026thinsp;1.63\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.91\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e98.58\u0026thinsp;\u0026plusmn;\u0026thinsp;2.19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e2.22\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e77.85\u0026thinsp;\u0026plusmn;\u0026thinsp;0.23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.29\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e104.20\u0026thinsp;\u0026plusmn;\u0026thinsp;2.79\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e2.68\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFenvalerate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eAcetamiprid\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e82.55\u0026thinsp;\u0026plusmn;\u0026thinsp;2.20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2.67\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e89.95\u0026thinsp;\u0026plusmn;\u0026thinsp;1.11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e1.23\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.075\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e76.70\u0026thinsp;\u0026plusmn;\u0026thinsp;1.59\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2.08\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.075\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e95.40\u0026thinsp;\u0026plusmn;\u0026thinsp;2.50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e2.62\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e83.47\u0026thinsp;\u0026plusmn;\u0026thinsp;1.83\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2.19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e99.68\u0026thinsp;\u0026plusmn;\u0026thinsp;4.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e4.01\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e80.95\u0026thinsp;\u0026plusmn;\u0026thinsp;2.29\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2.82\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e96.18\u0026thinsp;\u0026plusmn;\u0026thinsp;3.13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e3.25\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e77.58\u0026thinsp;\u0026plusmn;\u0026thinsp;1.36\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.76\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e102.17\u0026thinsp;\u0026plusmn;\u0026thinsp;1.65\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e1.62\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"6\"\u003e*Mean of three replications, SD- Standard Deviation, RSD- Relative Standard Deviation\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec23\" class=\"Section2\"\u003e \u003ch2\u003e3.4. Monitoring of market and farmgate bitter gourd samples for insecticides residues\u003c/h2\u003e \u003cp\u003eBiosensor based detection method was validated by performing a twostep experiment. In first step the linearity, recovery, LOD and LOQ of the developed biosensor in bitter gourd sample were determined. In the second step, bitter gourd samples collected from farmgate and market were subjected to bioanalysis using developed biosensor and the results were compared with GC-MS/LC-MS) (Table\u0026nbsp;\u003cspan refid=\"Tab10\" class=\"InternalRef\"\u003e10\u003c/span\u003e). The monitoring results showed that four out of twenty bitter gourd samples were found to have detectable residues of imidacloprid residues (LOQ-0.025 mg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) in LC-MS. The samples were found to contain imidacloprid residues in four samples ranging from 0.011\u0026ndash;0.055 mg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. In none of the sample imidacloprid residues exceeded MRL level set by the European Union (EU, 2022). The EU MRL for imidacloprid in bitter gourd is 0.2 mg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab10\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 10\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eDetection of selected insecticides residues in market and farmgate bitter gourd samples using different analytical methods\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"8\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eS. No.\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eSample\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eInsecticides\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eGC/LC-MS\u003c/p\u003e \u003cp\u003e(mg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e \u003cp\u003ePotentiometric method\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c8\" namest=\"c7\"\u003e \u003cp\u003eAmperometric method\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eInhibition (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eResidue (mg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eInhibition (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003eResidue (mg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSample 1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eND\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSample 2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eND\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSample 3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eND\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e4.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSample 4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eImidacloprid\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.060\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e43.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.051\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e28.56\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.063\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e5.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSample 5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eImidacloprid\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.058\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e42.20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.050\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e24.55\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.055\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e6.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSample 6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eND\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e7.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSample 7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eND\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e8.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSample 8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eND\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e9.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSample 9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eND\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e10.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSample 10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eImidacloprid\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.042\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eBLQ\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eBLQ\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eBLQ\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eBLQ\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e11.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSample 11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eND\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e12.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSample 12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eND\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e13.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSample 13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eND\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e14.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eSample 14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eImidacloprid\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.099\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e76.37\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.090\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e45.17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.10\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eFenvalerate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.010\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eBLQ\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eBLQ\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eBLQ\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eBLQ\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e15.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSample 15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eND\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e16.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSample 16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eND\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e17.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSample 17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eND\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e18.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSample 18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eND\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e19.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSample 19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eND\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e20.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSample 20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eFenvalerate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.020\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eBLQ\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eBLQ\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eBLQ\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eBLQ\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"8\"\u003eND- Not Detected, BLQ-Below the Limit of Quantification - GC-MS (0.01 mg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e), LC-MS (0.025 mg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) and Potentiometric/Amperometric methods (0.05 mg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eIn potentiometric and amperometric methods, detection and quantification of insecticide residues in samples was standardized based on per cent inhibition in current at LOQ level (0.05 mg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e). The per cent inhibition recorded was 16.55 and 25.63% lambda cyhalothrin, 20.04 and 29.04% deltamethrin, 30.05 and 27.30% fenvalerate, 16.62 and 22.24% imidacloprid, 20.27 and 23.87% thiamethoxam and 17.23 and 32.00% acetamiprid. By employing potentiometric technique, the residues of imidacloprid were detected in three bitter gourd samples ranged from 0.050\u0026ndash;0.090 mg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e with respective inhibition percentages ranging from 42.20 to 76.37. In amperometric method, imidacloprid residues were found in three samples (0.055-0.10 mg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) and the corresponding inhibition percentages were in the range of 20.97\u0026ndash;45.17. Borah et al. (\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2018\u003c/span\u003e) developed GST enzyme-based biosensor to detect residues of five insecticides in potato using amperometric method and compared with the results of GC-MS. LOD of amperometric method was calculated in carbendazim (0.002 ppm), chlorpyriphos (0.06 ppm), DDT (0.04 ppm), dinocap (0.05 ppm) and ethion (0.1 ppm) with 10 per cent inhibition. While, GC-MS analysis found LOD at 0.01 ppm and recovery rate of five insecticides ranged from 88 to 100 per cent in potato samples, whereas biosensor recovery from potato samples ranged from 25 to 101 per cent.\u003c/p\u003e \u003cp\u003eThe application of the developed biosensor analysis for monitoring bitter gourd samples were shown in the present study. The developed biosensor method does not require any sample extraction, clean up procedures, low cost and real samples can directly be analysed using biosensor probe. In GC-MS/LC-MS analysis, pre-treatment procedures were required before residue analysis and chromatographic methods for residue detection are generally laborious, time consuming and require expensive sophisticated instruments (Hassani et al., \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Zamora et al., \u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). Our study laid a foundation for the development of a biosensor-based device for in-situ detection of synthetic pyrethroid and neonicotinoid insecticide residues in harvested agricultural produce.\u003c/p\u003e "},{"header":"Conclusion","content":" \u003cp\u003eThe standardised GST biosensor based method has the ability for the in-situ detection of insecticide residue in vegetable and it requires no clean-up and extraction steps. The method uses the GST catalyzed in vitro detoxification reaction between glutathione and 1-chloro-2,4-dinitrobenzene as the benchmark reaction. This biosensor can be employed for rapid detection of synthetic pyrethroid (lambda cyhalothrin, deltamethrin and fenvalerate) and neonicotinoid (imidacloprid, thiamethoxam and acetamiprid) residues. The detection accuracy of biosensor results was confirmed through GC-MS/LC-MS analysis. The average recovery, sensitivity and precision of synthetic pyrethroid and neonicotinoid detection in the actual samples of bitter gourd showed good potential for the application in food safety.\u003c/p\u003e "},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eCRediT authorship contribution statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eM. M. Mawtham:\u0026nbsp;\u003c/strong\u003eMethodology, Investigation, Formal analysis, Writing-original draft, formal analysis, Visualization.\u0026nbsp;\u003cstrong\u003eK.\u003c/strong\u003e \u003cstrong\u003eBhuvaneswari:\u0026nbsp;\u003c/strong\u003eMethodology, Conceptualization, Supervision, Writing-review \u0026amp; editing.\u0026nbsp;\u003cstrong\u003eS.\u003c/strong\u003e \u003cstrong\u003eThirumalairajan:\u0026nbsp;\u003c/strong\u003eResources, Investigation, Formal analysis.\u0026nbsp;\u003cstrong\u003eA. Suganthi:\u0026nbsp;\u003c/strong\u003eResources, Supervision.\u0026nbsp;\u003cstrong\u003eS. Kulanthaisami:\u0026nbsp;\u003c/strong\u003eResources, Investigation.\u0026nbsp;\u003cstrong\u003eK. S. Subramanian:\u0026nbsp;\u003c/strong\u003eResources,Investigation.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDeclaration of Competing Interest\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors are thankful to the Pesticide Toxicology Laboratory, Department of Agricultural Entomology, Centre for Plant Protection Studies and Department of Nano Science \u0026amp; Technology, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India, for providing necessary facilities during the study. This work was supported by Jawaharlal Nehru Memorial Fund, New Delhi, India [SU-1/1454/2022-23/78].\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eChemical compounds studied in this article:\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eLambda-Cyhalothrin (PubChem \u003ca href=\"CID:443046\"\u003eCID:443046\u003c/a\u003e)\u003c/p\u003e\n\u003cp\u003eDeltamethrin (PubChem \u003ca href=\"CID:40585\"\u003eCID:40585\u003c/a\u003e)\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eFenvalerate (PubChem \u003ca href=\"CID:3347\"\u003eCID:3347\u003c/a\u003e) \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eImidacloprid (PubChem \u003ca href=\"CID:86287518\"\u003eCID:86287518\u003c/a\u003e)\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThiamethoxam (PubChem \u003ca href=\"CID:107646\"\u003eCID:107646\u003c/a\u003e)\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAcetamiprid (PubChem \u003ca href=\"CID:213021\"\u003eCID:213021\u003c/a\u003e) \u0026nbsp;\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eAlbuquerque YDT, Ferreira LF (2007) Amperometric biosensing of carbamate and organophosphate pesticides utilizing screen-printed tyrosinase-modified electrodes. 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Molecules 24(14):2659. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.3390/molecules24142659\u003c/span\u003e\u003cspan address=\"10.3390/molecules24142659\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[{"identity":"268bb5ec-2691-4ace-b10c-cf75897970b6","identifier":"10.13039/501100004021","name":"Jawaharlal Nehru Memorial Fund","awardNumber":"SU-1/1454/2022-23/78","order_by":0}],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"Tamil Nadu Agricultural University","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Insecticide, bitter gourd, Glutathione-S-Transferase, biosensor, GC-MS/LC-MS, food safety","lastPublishedDoi":"10.21203/rs.3.rs-4900144/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4900144/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe food safety issues related to the pesticide residues in agricultural produce have increased the demand for instruments that can rapidly, sensitively, and selectively detect pesticide residues in food commodities. This idea served as the impetus for the development of protocols for the detection and quantification of various insecticide residues using GST-based biosensor probes. We demonstrated the effectiveness of GST-based biosensor and compared with analytical methods such as GC-MS/LC-MS for application in detection of multi-residue insecticides \u003cem\u003eviz.\u003c/em\u003e, synthetic pyrethroid and neonicotinoid in bitter gourd samples. Spectrophotometric analysis was confirmed from Michaelis-Menten constant (\u003cem\u003eK\u003c/em\u003e\u003csub\u003e\u003cem\u003em\u003c/em\u003e\u003c/sub\u003e) and maximum velocity (\u003cem\u003eV\u003c/em\u003e\u003csub\u003e\u003cem\u003emax\u003c/em\u003e\u003c/sub\u003e) in the range 0.00178\u0026ndash;0.00767 M and 0.01519\u0026ndash;0.05249 mM/s for six different insecticides. Further, GST-based biosensor for the detection of various insecticides showed good linear curve (R\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.98) in the range from 0.01 to 0.5 mg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e with LOD and LOQ calculated in 0.01 and 0.05 mg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. Method validation parameters namely linearity, recovery inhibition were calculated 1.83\u0026ndash;65.10%, accuracy (71\u0026ndash;100%) and precision (RSD\u0026thinsp;\u0026lt;\u0026thinsp;6.0%), respectively. Among the 20 farmgate and market samples subjected to different techniques, imidacloprid residues were detected in four bitter gourd samples ranging from 0.042 to 0.099 mg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e in LC-MS and 0.050\u0026ndash;0.10 mg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e for three samples in GST-based biosensor techniques.\u003c/p\u003e","manuscriptTitle":"Detection of multi-residue insecticides in bitter gourd using Glutathione-S-Transferase enzyme based different analytical techniques","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-08-13 09:00:30","doi":"10.21203/rs.3.rs-4900144/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"61458750-94ac-4114-98ea-2a6e512cafb2","owner":[],"postedDate":"August 13th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":35923598,"name":"Food Science \u0026 Technology"}],"tags":[],"updatedAt":"2024-08-13T09:00:30+00:00","versionOfRecord":[],"versionCreatedAt":"2024-08-13 09:00:30","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4900144","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4900144","identity":"rs-4900144","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}