Investigation of electrochemical properties and detection of the antiarrhythmic drug amiodarone in pharmaceutical and urine samples using a disposable pencil graphite electrode

Investigation of electrochemical properties and detection of the antiarrhythmic drug amiodarone in pharmaceutical and urine samples using a disposable pencil graphite electrode | 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 Investigation of electrochemical properties and detection of the antiarrhythmic drug amiodarone in pharmaceutical and urine samples using a disposable pencil graphite electrode Sülbiye DOĞAN, Abdulkadir LEVENT This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5677107/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 6 You are reading this latest preprint version Abstract The electrochemical properties of the antiarrhythmic drug amiodarone were investigated using square-wave and cyclic voltammetry techniques in Britton–Robinson buffer solution (pH 5.0) with a disposable electrochemical activated pencil graphite electrode. In cyclic voltammetry measurements, it was observed that amiodarone exhibited a well-defined irreversible oxidation peak at a voltage of approximately + 0.94 V. With optimized instrument parameters, amiodarone exhibited a linear response in the concentration range of 0.125 µg/mL to 6.862 µg/mL in Britton–Robinson buffer solution (pH 5.0) on a disposable electrochemical-activated pencil graphite electrode. The resulting calibration curve was Ip(µA) = 0.113 C(µg/mL) + 0.039 ( r = 0.998, n = 9). The limit of detection and limit of quantification values for the voltammetric method were determined to be 0.027 µg/mL and 0.089 µg/mL, respectively. The simplicity, rapidity, and sensitivity of the developed voltammetric method are considered to be important advantages. In addition, the applicability of the proposed voltammetric method to drug and urine samples demonstrated the selectivity of the method. The results of the voltammetric technique developed for the analysis of amiodarone in pharmaceutical samples were supported by spectrophotometric results. Amiodarone Antiarrhythmic drug Disposable pencil graphite electrode Voltammetry Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Introduction Amiodarone (AMD, (2-butyl-1-benzofuran-3-yl)-[4-[2-(diethylamino)ethoxy]-3,5-diiodophenyl]methanone) (Figure SI 1) was formulated in the early 1960s as an alternative therapeutic agent for angina pectoris due to its coronary vasodilatory characteristics and ability to decrease myocardial oxygen demand. However, the drug's strong antiarrhythmic effects(prevention of irregular heartbeat) have come to the fore, and its use has been directed accordingly [ 1 ]. AMD is a class III antiarrhythmic drug commonly used to treat and prevent a variety of irregular heartbeats, including ventricular tachycardia, ventricular fibrillation, and complex tachycardia [ 1 ]. Compared with other antiarrhythmic drugs, AMD was reported to be more effective in the treatment of both supraventricular and ventricular arrhythmias [ 2 ]. Although AMD is an effective drug, its use is complicated by high toxicity, and there are many clinical reports highlighting lung, thyroid, eye, and liver toxicity resulting from drug therapy [ 3 ]. Measuring and quantifying the amount of drugs in body fluids and drug samples is important in clinical chemistry, toxicology, doping analysis, and drug research. The therapeutic effect of drugs depends on their concentration in body fluids. However, reliable analytical methods are required to check the pharmaceutical research process, drug discovery, drug development, and drug manufacturing [ 4 ]. The pharmaceutical analysis involves analytical studies covering various drug development and manufacturing stages. These analytical studies are critical to ensuring that active pharmaceutical ingredients, drug dosage forms, and final pharmaceutical products are safe, effective, and of high quality. Therefore, researchers have used many analytical techniques to determine the concentrations of pharmaceutically important active drug substances. According to our best literature search, some analytical methods were identified for the analysis of AMD in different matrix media: high-performance liquid chromatography [ 5 – 10 ], liquid chromatography-mass spectrometry [ 11 ], Fourier-transform infrared spectroscopy [ 12 ], and Fourier transform ion cyclotron resonance mass spectrometry [ 13 ]. In addition, electrochemical properties and quantification of AMD were carried out using carbon paste electrode [ 14 ], magnetic (Fe 2 O 3 ) mobile crystalline material-41 grafted with 3-aminopropyl groups [ 15 ], and molecularly imprinted/carbon nanofibers [ 16 ]. It appears that the electrodes used for assessing the electrochemical properties and quantifying AMD require modification. Modification of carbon paste electrodes is generally a simple process. However, synthesizing new modification agents may be disadvantageous due to factors such as high cost, requirement for toxic reagents and time-consuming processes. No electrochemical method using electrochemical-activated disposable pencil graphite electrodes (E-PGE) for the determination of AMD was found in the literature search. Accordingly, this study was conducted using a disposable E-PGE. The selection of this electrode was based on its advantageous characteristics, including high electrochemical reactivity, well-defined adsorption properties, a wide potential window, excellent mechanical stability, cost-effectiveness, low background current, and ease of modification, making it a highly suitable working electrode for electrochemical applications [ 17 – 26 ]. In this study, the analysis of AMD in pharmaceutical and urine samples was successfully performed on disposable E-PGE using a green voltammetric technique, an environmentally friendly approach to electrochemical analysis that minimizes the use of toxic reagents, hazardous solvents, and excessive waste production. Material and Methods Reagents Amiodarone HCl (A8423, Sigma Aldrich), sodium hydroxide (Sigma-Aldrich, reagent grade, ≥98%, pellets (anhydrous)), hydrochloric acid (Sigma-Aldrich, 37%, ACS reagent), potassium hexacyanoferrate(III)hydrochloric acid (Sigma-Aldrich, ACS reagent, ≥99.0%), potassium hexacyanoferrate(II) trihydrate (Sigma-Aldrich, ACS reagent, 98.5-102.0%), citric acid (Sigma-Aldrich, ACS reagent, ≥99.5%), sodium citrate (Sigma-Aldrich, pharmaceutical secondary standard), glacial acetic acid (Sigma-Aldrich, glacial, ACS reagent, ≥99.7%), phosphoric acid (Sigma-Aldrich, ACS reagent, ≥85 wt. % in H2O), boric acid (Sigma-Aldrich, ACS reagent, ≥99.5%), di-Sodium hydrogen phosphate dihydrate (Sigma-Aldrich, buffer substance for chromatography LiChropur™) and ethanol (Sigma Aldrich, ≥99.9% (GC), gradient grade, suitable for HPLC, gradient grade, LiChrosolv®) were used in this study. Instruments Autolab PGSTAT128N was used as the electrochemical analyzer in the experiments. Disposable pencil lead (Tombo 0.5/2B Japan) was used as the working electrode, an Ag/AgCl (3 M NaCl) (MF 1063; BASi) as the reference electrode, and a platinum wire (MF 1032, BASi) as the auxiliary electrode. The experiments were performed in a 10 mL 3-compartment capped standard glass cell (MR1208, BASi). ARE heating magnetic stirrers, and magnetic stir bars (Spinbar VMR) were used to mix the solutions. A Thermo Scientific Orion 3 Star pH meter was used for pH measurements and a Precisa 320XB 220A precision balance for accurate weighing. The Shimadzu 1900 spectrophotometer was used to obtain the UV-Vis spectrum, and the ZEISS-LEO 1430 SEM devices were used. Preparation of solutions AMD HCl stock solution was prepared in ethanol at 3.41 mg/mL. Voltammetric experiments were carried out in different supporting electrolytes. For this purpose, various buffer solutions such as 0.1 mol/L acetate (ABS) pH=4.8, 0.1 mol/L citrate (CR) pH=4.8, 0.04 mol/L Britton-Robinson (BR) between pH 2.0 and pH 11.0, and 0.1 mol/L phosphate (PBS) pH=2.0, pH=3.0, and pH=7.4 were used. The pHs of these solutions were adjusted with 0.5 mol/L NaOH or 0.5 mol/L HCl solutions. The buffer solutions were stored in a refrigerator in Pyrex® glass bottles when not in use. Voltammetric measurements In the voltammetic analysis studies, the triple electrode system of BASi Company was used. For single-use PGE, a 0.5 Rotring T 0.5 tipped pen and the pen tips required for this (Model, Tombow 0.5/2B Japan) were commercially obtained from a stationery. These tips were cut to a length of 30 mm and placed in the tipped pen, leaving 15 mm of the tip outside. The conductivity between the pen tip and the potentiostat was provided by copper wire. This PGE was electrochemically activated for 60 s at +1.4 V potential in the selected supporting electrolyte solution before the electrochemical measurements [27, 28]. This type of activation was done to obtain uniform and more repeatable signals. Experiments were performed using a new pen tip for each analysis. After PGE was electrochemically activated in the selected supporting electrolyte medium, cyclic voltammetry, square-wave, and differential pulse experiments were performed in the range of 0 V to +1.45 V. Experiments were carried out to optimize the deposition potential (0 V- 0.7 V) and deposition time (0 s – 150 s) for the adsorptive anodic signal of AMD on the E-PGE surface. In addition, optimization studies were carried out for step potential (1 mV- 9 mV), modulation amplitude (10 mV- 80 mV) and frequency (10 Hz-90 Hz) values within the scope of optimization of square-wave voltammetry parameters. Under these optimum conditions determined for AMD, the square-wave voltammetry technique was used for analysis in pharmaceutical and urine samples. Preparation of real samples Amidovin (150 mg/3 mL, Tüm Ekip Pharmaceuticals Inc., İstanbul) ampoules were purchased from pharmacies in Turkey for analytical applications. Firstly, an aliquot 10 µL of Amidovin sample was taken, and diluted with BR (pH 5.0) supporting electrolyte solution to make a total volume of 10 mL. Then, 100 µL of this solution was added to the electrochemical cell containing 10 mL of supporting electrolyte, and the mixture was vigorously stirred. After this, SWV experiments were performed without any sample pretreatment. The voltammetric procedure described in the section (voltammetric measurements) was applied and the voltammograms for the ampoule solutions were recorded. Then, the standard addition method was applied to the electrolyte in a similar manner to construct the recovery curves before fortification (artificial contamination) and without fortification. Recovery curves were performed in triplicate, and mean recovery values were calculated using the same methodology effectuated in the pure electrolyte. The amount of AMD in the Amidovin ampoule and recovery studies were performed using the multiple standard addition method. A urine sample was collected from a healthy volunteer immediately prior to the experiments with the approval from the Batman University Non-Interventional Clinical Research Ethics Committee (27.02.2024-E.153368). For analysis, 5 mL of urine sample was added to each of two 10 mL test tubes. One test tube was diluted with BR buffer (pH 5.0), and the voltammogram of this sample was recorded (Figure 7). The other test tube contained urine, BR buffer, and a final concentration of 0.125 μg/mL of AMD. Then, AMD additions were made to the final solutions in the range of 0.624 μg/mL to 4.991 μg/mL, and % recovery calculations were made (Table 3). In order to ensure homogeneity and interaction in these samples, the samples were mixed for 5 minutes at 3000 rpm using an IKA MS 3 Basic Vortex Tube Mixer. The urine samples were analyzed using the voltammetric procedure as described in the section (voltammetric measurements), and their voltammograms were recorded. The analysis of AMD in urine samples and recovery studies was performed using the multiple standard addition method. Results and Discussion Electrochemical activation of PGE In this study, in order to obtain more sensitive, responsive, and reproducible signals on the PGE surface, electrochemical activation of PGE was carried out in the supported electrolyte medium. The characterization of bare PGE and E- PGE was investigated in detail using cyclic voltammetry, electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM) techniques. Here, EIS analyzes the behavior of the electrode-electrolyte interface by determining parameters such as charge transfer resistances, double layer capacitance, and diffusion processes occurring on the electrode surface. Thus, it provides important information in many areas, such as material characterization, evaluation of electrode modifications, and elucidation of reaction mechanisms [29]. Cyclic voltammetry (100 mV/s voltage scan rate) and EIS (at a sinusoidal potential of +0.25 V, and conducted between 100 mHz and 0.1 Hz) measurements were performed on the redox probe 2.5 mol/L ([Fe(CN) 6 ] 4-/3- ) containing 0.1 mol/L KCl. The surface areas of bare PGE and E-PGE electrodes were determined by recording the cyclic voltammograms in a 0.1 mol/L supporting electrolyte solution containing 2.5 mmol/L of a redox probe. The anodic peak current values obtained from the cyclic voltammograms were used to calculate the effective surface areas of bare PGE and E-PGE using the Randles-Sevcik equation [29] [ ], where n represents the number of electrons transferred during the electrode reaction, taken as 1 for the redox probe. D denotes the diffusion coefficient of the redox probe, with a value of 7.6×10⁻⁶ cm²/s. v is the scan rate (V/s), C is the concentration of the redox probe, and A represents the effective surface area of the electrodes. The calculated effective surface areas were 0.009 cm² for bare PGE and 0.011 cm² for E-PGE. Moreover, the cyclic voltammetry results given in Figure SI 2a show that E-PGE exhibits higher current density compared to bare PGE. This indicates that electrochemical activation increases the electrode surface area, strengthens the interaction with the redox probe, and improves the electron transfer kinetics. The potential difference between the anode and cathode current peaks for bare PGE and E-PGE was found to be 0.56 V and 0.25 V, respectively. As a result, the decrease in the potential difference between the anode and cathode current peaks of E-PGE supports a faster and more efficient electron transfer mechanism. The EIS results presented in Figure SI 2b quantitatively reveal the difference between the electrochemical properties of bare PGE and E-PGE. Here, the charge transfer resistances (Rct) for bare PGE and E-PGE were found to be 8950 Ω and 2105 Ω, respectively. According to the Nyquist diagram, bare PGE has a larger semicircle, indicating a higher Rct. In contrast, the smaller semicircle in E-PGE confirms that Rct decreases and the electron transfer kinetics at the electrode surface accelerates. When the EIS data are analyzed in accordance with the equivalent circuit model (Figure 2b, inset), it is seen that E-PGE presents a more advantageous structure electrochemically with a lower Rct value. These findings reveal that electrochemical activation causes significant structural and electronic changes on the PGE surface, making the electrode more sensitive to the redox probe. Figure SI 3 shows the images of bare PGE (a) and E-PGE (b) surfaces obtained by SEM. When the images are analysed, it is observed that the bare PGE surface is relatively smooth and has low porosity (Figure SI 3a). This structure indicates that the electrode surface offers a limited active area and is not sufficiently favourable for electron transfer processes. In contrast, the E-PGE surface obtained after electrochemical activation (Figure SI 3b) exhibits significant morphological changes. As a result of the activation process, a more porous, rough, and heterogeneous structure was observed on the surface. This change leads to an increase in the electrode surface area and provides more active sites for electrochemical reactions. Moreover, the particle formations and crack-like structures observed on the surface are thought to improve the electrochemical performance by reducing the charge transfer resistance. These results show that the electrochemical activation process leads to significant structural changes on the surface of the PGE, as directly observed by SEM. Additionally, cyclic voltammetry and EIS provide indirect evidence of these electrochemical activation process, demonstrating the improved electrochemical properties of the electrode and resulting in a more efficient electrode surface. Cyclic voltammetry results of amiodarone on E-PGE In this part of the study, cyclic voltammetry analysis was performed using a 0.682 mg/mL of AMD in BR (pH 5.0) buffer with disposable E-PGE. This analysis was performed in the voltage range from 0 V to +1.5 V and at a scanning speed of 100 mV/s. Figure 1a shows a three-cycle voltammogram of AMD in BR (pH 5.0) buffer. When these voltammograms were examined, an oxidation wave occurred at approximately +0.94 V potential. Based on the increase in the number of cycles, there was a decrease in the anodic peak signal intensity and this voltammogram wave became more widespread. The decline in anodic peak current suggests progressive changes at the electrode surface, such as passivation, fouling, or material degradation, which hinder the redox reaction efficiency over multiple cycles. Figure 1b presents the cyclic voltammetry results obtained for a 0.682 mg/mL AMD solution in BR buffer (pH 5.0) over a scan rate range of 25 mV/s to 500 mV/s. The oxidation peak potential exhibited a shift towards more positive values as the scan rate increased. In this process, corresponding to voltage scanning rates of 25 mV/s, 50 mV/s, 100 mV/s, 200 mV/s, 300 mV/s, 400 mV/s, and 500 mV/s, respectively, +0.921 V, +0.932 V, +0.954 V, +0.965 V, +0.971 V, +0.984 V and +1.013 V values were observed. To investigate the underlying electrochemical processes governing AMD oxidation on E-PGE, the relationship between the anodic peak current and potential with respect to scan rate variations was analyzed. These findings suggest that the electrochemical behavior of AMD on E-PGE is influenced by the scan rate under the given experimental conditions. Specifically, at lower scan rates, the oxidation peak potential appeared at more negative values, whereas at higher scan rates, a shift towards more positive potentials was observed. This behavior provides insights into the possible involvement of adsorption, diffusion, and electron transfer phenomena in the electrochemical mechanism of AMD oxidation [29]. By evaluating the data in the voltammograms recorded in Figure 1b and Figure SI 4, the Ip/√ v relationship [Ip (µA) =0.370√ v + 0.335, r =0.99] (Figure SI 4a), the Ip/ v relationship [Ip(µA) = 0.54 v +12.61, r = 0.91] (Figure SI 3b), and the logIp/log v relationship [logIp (µA) = 0.78log v + 0.89, r = 0.97] (Figure SI 4c) were calculated. In the case of adsorption-controlled behavior, the slope of the logIp/logv graph is ideally found to be 1. In such a case, Ip also changes linearly, proportional to v [30]. If diffusion-induced adsorption is the case, the slope value obtained for the equation between logIp and log v will be between 0.5 and 1. On the other hand, in a completely diffusion-controlled process, the slope value will be 0.5. In this study, there was a linear change between Ip and √ v , and the slope of the equation between logIp and logv was between 0.5 and 1 (logIp(µA) = 0.78log v + 0.89, r = 0.97). When these findings are taken together, the electrochemical process on the disposable PGE surface may be diffusion-induced adsorption. As seen in Figure 1b, the anodic peak voltages shift to a more positive region in the range of 25-500 mV/s scan speeds. This phenomenon indicates an irreversible electrochemical reaction mechanism. The relationship between the anodic peak potential (Ep) and the scan rate ( v ) is expressed by the following equation: Ep =E 0 + (2.303RT / αnF) log (RT k / αnF) + (2.303RT / αnF) log v [31]. In this equation, E 0 represents the standard electrode potential, k represents the heterogeneous electron transfer rate constant, α represents the charge transfer coefficient and n represents the number of electrons transferred in the redox reaction. The constants are the gas constant (R = 8.314 J K / mol), temperature (T = 298 K), charge transfer coefficient (α= 0.5), and Faraday constant (F = 96485.33 C/mol). The Ep - log v linear relationship obtained on the PGE surface under optimum operating conditions is determined as follows: Ep(V)=0.061 logν (mV/s) + 0.742. Based on this relationship, the slope value is calculated as 0.061. As a result of the relevant calculations, the number of transferred electrons is found as n = 1.94 and is accepted as approximately 2. In light of this information, the possible electrochemical mechanism occurring on E-PGE may be as follows (Figure 2). When 1 e - is removed from the AMD compound, radical carbocation is formed on the furan ring [32]. In this process, this radical loses another 1 e - and di-carbocation is formed. In this structure, one of these carbocations is mesomerically stable due to the effect of the neighboring group since it is adjacent to the oxygen atom, while the other carbocation is mesomerically stable by the aromatic ring since it is in the aryl position. Following the attachment of the water molecule to these positively charged carbons, a diol is formed by removing one H + from each. Impact of supporting electrolyte and pH In electrochemical analysis, the selection of the supporting electrolyte composition and pH is of great importance in evaluating the electrochemical behavior of the substance on the electrode surface [28]. These selections have a significant effect on the accuracy, sensitivity, and reliability of the analysis by affecting the redox properties of the analyte compound. While BR is a multi-purpose buffer solution covering a wide pH range [33], ABS, CR, and PBS buffers are also effective solutions at certain pH [34]. Based on this information, in this part of our investigation, 0.04 mol/L BR buffer (Figure 3a) with a pH range of 2.0-12.0, 0.1 mol/L PBS (pH 2.0, 3.0, 7.4), 0.1 mol/L CR (pH, 4.8), and 0.1 mol/L ABS (pH 4.8) buffers (Figure 3b) were used to record voltammograms from 0.136 mg/mL AMD on single-use E-PGE with the square-wave voltammetric technique. When Figures 3a and 3b are reviewed in depth, the most appropriate supporting electrolyte is BR, with a pH of 5.0. In addition, as can be seen in the experiments carried out on different types of supporting electrolytes, it was clearly determined that the anodic signal intensity of AMD around pH = 5 (±1) was higher (Figure 3b). As the pH of all supporting electrolytes increases, the anodic peak potential value moves to the more negative area. These results were found to be compatible with the literature [32]. When the data presented in Figure 3 is evaluated, significant changes in the Ep and peak current are observed depending on the pH change. This clearly shows that the electrochemical process occurring on the E-PGE surface progresses with the contribution of protons. The change of the anodic peak potential with pH is expressed with a linear relationship, and the obtained equation is as follows: Ep(V)= -0.052 pH + 4.13 (Figure SI 5). Based on this relationship, it can be said that proton and electron transfers occur at equal rates in the electrochemical process occurring on the E-PGE surface of AMD under operating conditions. Selection of voltammetric technique To perform the analysis of AMD in pharmaceutical and urine samples more sensitively and precisely, square-wave and differential pulse voltammetry techniques were used on the E-PGE surface. For this purpose, voltammetric experiments were carried out in BR (pH 5.0) medium. As can be seen in Figure SI 6, the anodic signal intensity of AMD was 45% higher when the square-wave technique was used. Thus, in the following sections of the analytical study, unless otherwise stated, the square-wave voltammetry technique will be used as the voltammetric technique. Influence of deposition and square-wave parameters on electrode response In this part of the study, the effect of deposition voltage and time on the electrode response were investigated to achieve more sensitive and reproducible signals on E-PGE. Measurements were performed using 0.102 mg/mL AMD in BR buffer (pH 5.0) with 60 s accumulation time in the voltage range of 0 V to +0.7 V. The highest peak current was recorded at +0.4 V (Figure SI 7a). Therefore, in the continuation of the study, +0.4 V deposition voltage was applied on E-PGE, and voltammograms were recorded at deposition times ranging from 0 s to 150 s (Figure SI 7b). The anodic peak current intensity increased rapidly up to 90 s and then decreased significantly. The anodic peak current intensity exhibited a rapid increase up to 90 seconds, reaching its maximum value, after which it significantly decreased. This behavior suggests an initial accumulation of electroactive species on the electrode surface, followed by a decline possibly due to surface saturation, desorption effects, or diffusion limitations. Along with the analytical investigation, optimization experiments for the device settings employed in the square-wave voltammetry technique were thoroughly investigated in order to obtain the most sensitive and symmetric voltammograms on E-PGE [35]. In this way, experiments were performed with frequency (10 Hz -90 Hz), step voltage (1 mV-9 mV), and amplitude (10 mV-80 mV) as square-wave parameters. These experiments were carried out in the BR (pH 5.0) supporting electrolyte solution containing 0.102 mg/mL AMD. During the measurements, the influence of each parameter was investigated while the values of the other two parameters remained constant. Under constant amplitude and frequency settings, raising the step potential to 5 mV enhanced in peak intensity (Figure SI 8a). Nevertheless, it was noted that for step potential values greater than 5mV, the anodic peak flattened, and the residual current showed notable aberrations. A notable rise in anodic signal intensity was noted when the amplitude value was raised to 20 mV while maintaining a consistent step voltage and frequency (Figure SI 8b). When the amplitude values were above 20 mV, peak signal strength decreased. Finally, it was determined that with constant amplitude and step potential, the peak signal intensity increased with frequency up to 40 Hz, but decreased at higher values (Figure SI 8c). In this research, 90 s accumulation time, +0.4 V accumulation voltage, 5 mV step voltage, 20 mV amplitude, and 40 Hz frequency were accepted as the optimum values unless otherwise stated in the continuation of the analytical study. Analytical linear working range This section of the study focused on assessing the voltammetric approach utilizing E-PGE for the detection of AMD in urine and pharmaceutical samples, specifically evaluating its analytical working range, and reproducibility. Using the standard stock solution of 3.41 mg/mL AMD prepared in ethanol under optimum operating conditions, voltammograms were recorded by making known additions to the electrochemical cell (Figure 4). As can be seen in Figure 4, the anodic peak at +0.94 V was evaluated after each successive addition of the standard AMD solution. This anodic peak showed very good linearity [Ip(μA)=0.113 C(μg/mL) +0.039 ( r =0.998, n =9)] on E-PGE in the concentration range from 0.125 μg/mL to 6.862 μg/mL. From these data, the limit of detection (LOD = 3 s/m) and limit of quantification (LOQ = 10 s/m) were calculated [36]: In these equations, s represents the standard deviation of the peak current (as the average of 3 values) corresponding to the lowest concentration in the linearity range, while m represents the slope of the relevant calibration equation. Using the data here, the LOD value was found to be 0.027 μg/mL, and the LOQ value was found to be 0.089 μg/mL. The voltammetric method developed using single-use E-PGE for the analysis of AMD in different environments was compared with the analytical methods presented in Table 1 in terms of LOD values. As can be seen from these results, the LOD value of 0.027 μg/mL obtained with single-use PGE is very good. The E-PGE used in the square-wave voltammetric technique is more cost-effective than complex electrode materials (e.g., Fe₂O₃-MCM-41-nPrNH₂-CPE) used in other methods [15, 16], making it economically advantageous option. The E-PGE electrodes used in the method stand out as an environmentally friendly alternative since they do not contain expensive or toxic reagents. Compared to HPLC [6–8, 10, 11], which requires high organic solvent consumption, this method uses fewer chemicals. At the same time, the general advantages of electrochemical methods, fast analysis time and simple device requirements are quite advantageous compared to chromatographic methods. In order to test the repeatability level of the single-use E-PGE chosen as the working electrode, 2.495 μg/mL AMD solution was prepared. Under optimum experimental conditions, square-wave voltammograms of this AMD solution were recorded nine times on the same day using E-PGE. The oxidation peak current and voltage data from these recorded voltammograms were used for computations. Thus, the RSD value for the oxidation peak current was 3.84% (3.62 % RSD), and the oxidation voltage value was 0.42% (3.34 % RSD). Table 1. Analytical performance of analytical techniques proposed for the analysis of AMD in different matrix media Technique Electrode/Detector Linear concentration range (μg/mL) LOD (μg/mL) Matrix Reference HPLC UV 0-0.5 0.015 Horse Plasma [6] HPLC UV 0.01-5 0.01 Plasma [7] RP-HPLC UV 5-80 1.49 Pharmaceutical [10] HPLC UV 0.25-10 0.125 Pharmaceutical [8] LC-MS/MS UV 0.01–40.0 2700 Plasma [11] ASV CPE 0.0014-0.016 0.0001 Pharmaceutical [14] DPV Fe 2 O 3 –MCM-41–nPrNH 2 -CPE 3.07-484.08 1.43 Pharmaceutical [15] CV MIP/CNF 2-10 0.4 Plasma [16] SWV E-PGE 0.125-6.862 0.027 Pharmaceutical, Urine This work HPLC: High-performance liquid chromatography; RP-HPLC: Reversed-phase high-performance liquid chromatography; LC-MS/MS: Liquid chromatography-mass spectrometry/mass spectrometry; UV: Ultraviolet detector; ASV: Adsorptive stripping voltammetry; CPE: Carbon paste electrode; DPV: Differential pulse voltammetry; Fe₂O₃–MCM-41–nPrNH₂: mobile crystalline material-41-nPrNH₂-modified electrode; CV: Cyclic voltammetry; MIP/CNF: Molecularly imprinted polymer-modified carbon nanofiber electrode; SWV: Square-wave voltammetry; E-PGE; Electrochemical-activated disposable pencil graphite electrodes. Selectivity of the voltammetric method In the present study, the interference effects of ascorbic acid (AA), uric acid (UA), dopamine (DP), norepinephrine (NE), epinephrine (EP), progesterone (P4), sucrose (S), testosterone (TES) and some inorganic substances (Fe 2+ , Cu 2+ , Zn 2+ , Co 2+ , Ni 2+ , NO 3 - , Cl - , and SO 4 2- ), which may be present in biological fluids, on the voltammetric measurement of AMD were investigated. The AMD concentration was kept at 6.862 μg/mL, whereas the concentration of potentially interfering solutions was 10, 50, and 100 times higher. Figure 5 shows the voltammograms acquired from the measurements for the organic substances. As seen from the recorded voltammograms, it was determined that the tested analytes were not oxidized in the voltage range where AMD was oxidized on the E-PGE surface under these operating conditions. Additionally, it was determined that these analytes did not alter the anodic peak current signal intensity of AMD beyond ±5%. These findings demonstrate that the amount of AMD in bodily fluids may be consistently determined on E-PGE under these experimental settings. These particular interference investigations provide critical and significant information for the therapeutic use of these medications. Application to real samples In this part of the study, the applicability of the voltammetric method developed on disposable E-PGE was tested for pharmaceutical and urine samples. Amidovin (150 mg/3 mL, Tüm Ekip Pharmaceuticals Inc., İstanbul) ampoules supplied by pharmacies in Turkey were chosen for the pharmaceutical sample application. Quantification and recovery studies were carried out by applying the experimental protocols in the section ( preparation of real samples ). First, the square-wave voltammogram was recorded in 100 µL of Amivodin 10 mL of BR (pH 5.0) supporting electrolyte solution (Figure 6). We observed the anodic signal of standard AMD at +0.94 V. After this, when standard AMD (concentrations in the final solution, 0.652 μg/mL, 1.875 μg/mL, 3.743 μg/mL, and 6.354 μg/mL) was successfully added to this solution, the anodic peak signal of AMD increased linearly [Ip(μA)=0.103 C(μg/mL) +0.052 (r =0.989, n=5)]. The obtained results are presented in Table 2. The average of these results, AMD was measured as 152 mg / 3 mL with 102.25 % (4.25 % RSD) recovery in the Amidovin ampoule, which is very close to the 150 mg / 3 mL Amiodarone HCl level declared by the commercial company for each ampoule. This result shows that AMD can be analyzed with high accuracy in pharmaceutical samples using disposable E-PGE under optimum working conditions. In addition, to test the accuracy of the voltammetric technique developed on E-PGE, a spectrophotometric technique was used for the analysis of AMD in pharmaceutical samples. For this purpose, UV-visible spectra of AMD were recorded in the wavelength range of 200 nm to 800 nm (Figure SI 9). It was observed that AMD had maximum absorbance at 244 nm. At this wavelength, AMD gave a linear change of A(Au)=0.083 C [AMD] (μg/mL) -0.268, r=0.996 in the concentration range from 1.44 µg/mL to 10.06 µg/mL. Using the analytical calibration curve, AMD in the Amidovine ampoule was found to be 145.87 mg / 3 mL with 97.25 % (3.12 % RSD) recovery. It was observed that the results obtained by both techniques were consistent with each other. Table 2 . Square-wave voltammetric method analysis of Amidovin drug spiked with AMD standard solutions using E-PGE. Added a (µg/mL) Detected a,b (µg/mL) Recovery% c ±RSD% 0.498 0.505 101.41 ± 4.25 0.650 0.628 96.61 ± 4.02 1.874 1.955 104.32 ± 3.95 3.742 3.931 105.05 ± 4.18 6.353 6.603 103.93 ± 3.72 a Final concentration of AMD spiked into Amidovin drug in BR (pH 5.0) supporting electrolyte medium. b Values are the average of three independent analysis. c Recovery%:(detected/added)x100 The analysis of AMD in urine samples containing complex matrix was carried out by following the experimental protocol in the section ( preparation of real samples) . Here, firstly, the voltammogram of the urine sample in BR (pH 5.0) buffer solution medium was recorded (Figure 7). Under these study conditions, when only diluted urine sample was used, no signal was observed on E-PGE that could interfere with the anodic signal of AMD. This result shows that AMD can be analyzed safely in urine samples. For the second analysis, square-wave voltammograms were recorded after diluting 250 µL of AMD-containing urine sample with 10 mL of BR (pH 5.0) supporting electrolyte solution. Square-wave voltammograms were recorded by adding AMD with final concentrations ranging from 0.125 μg/mL to 4.991 μg/mL using the standard addition technique. The anodic peak of AMD observed at +0.94 V on disposable E-PGE increased in direct proportion to the amount of standard AMD added to urine samples. Here, with the addition of AMD, a good linearity was obtained between the anodic peak current and concentration. [Ip(μA)=0.148 C [AMD] (μg/mL) -0.103 ( r =0.987]. The results obtained are summarised in Table 3. According to these results, it was shown that AMD can be successfully analysed in urine samples with an average recovery of 99.46% (4.08% RSD). Table 3 . Square-wave voltammetric method analysis of urine samples spiked with AMD standard solutions using E-PGE. Added a (µg/mL) Detection a,b (µg/mL) Recovery% c ±RSD% 0.125 0.117 93.60 ± 4.12 0.624 0.608 97.44 ± 4.32 1.248 1.314 105.29 ± 4.19 1.872 1.781 95.14 ± 3.78 2.495 2.409 96.55 ± 3.98 3.119 3.229 103.53 ± 4.28 4.991 5.228 104.75 ± 3.92 a Final concentration of AMD spiked into urine samples in BR (pH 5.0) supporting electrolyte medium b Values are the average of three independent analysis c Recovery%:(detected/added)x100 Conclusion As a result of the literature review, it was determined that various studies were conducted using different analytical techniques for the analysis of AMD, a Class III antiarrhythmic drug. Studies using electrochemical techniques are relatively scare. Scientists have used disposable E-PGEs as electrode materials for years due to their economical, easily accessible, and renewable properties. In this present study, the electrochemical properties of AMD were investigated in different supporting electrolytes and a wide pH range by using these advantageous properties of E-PGE. In the supporting electrolyte medium of BR (pH 5.0), an irreversible wave was obtained at a potential of approximately +0.94 V with the cyclic voltammetry technique. In the evaluation of the data obtained from both cyclic and square-wave voltammetry techniques, an electrochemical mechanism for AMD on E-PGE was proposed. This electrochemical mechanism proves that 2 electrons and 2 protons contribute to the process. An electroanalytical technique was developed for the quantification of AMD in BR (pH 5.0) using the square-wave voltammetry. Good linearity was obtained between 0.125 μg/mL and 6.862 μg/mL of AMD under optimum operating conditions on disposable E-PGE. The LOD value of 0.027 μg/mL was calculated for single-use E-PGE, which is better than other analytical techniques. The accuracy of the method was tested by performing recovery studies on pharmaceutical and urine samples. In repeatability studies, the inter-day % RSD values for oxidation peak current and voltage were 3.84% and 0.42%, respectively. This shows that the precision of the method is good. Continuing the study, an interference study was performed with 6.862 μg/mL AMD in AA, UA, DP, NE, EP, P4, S, TES, and some inorganic substances (Fe 2+ , Cu 2+ , Zn 2+ , Co 2+ , Ni 2+ , NO 3 - , Cl - , and SO 4 2- ) solutions. In these interference experiments, the added substances did not cause an analytically significant change in anodic peak current and voltage for AMD. Thus, it was proven that AMD concentrations in biological fluids can be measured reliably voltammetrically. In general, it is considered that the developed square-wave voltammetric method may be an alternative to chromatographic and spectroscopic methods in the literature due to its advantages, such as being sensitive, fast, and economical, not requiring separation and purification, and being operable with small amounts of sample. Declarations Authors’ contributions Sülbiye DOĞAN: Conceptualization, Methodology, Investigation. Abdulkadir Levent : Validation, Data curation, Writing- original draft, Writing- review & editing, Supervision. Financial interests or Conflicts of interest: All authors certify that they have no affiliations with or involvement in any organization or entity with any financial interest or non-financial interest in the subject matter or materials discussed in this manuscript. Data availability Data will be made available on request. References Fatima N, Mandava K, Khatoon F, et al (2022) CLInical Profile and Side Effects of chronic use of oral Amiodarone in cardiology outpatients department (CLIPSE-A Study)- A prospective observational study. Annals of Medicine and Surgery 80:. https://doi.org/10.1016/j.amsu.2022.104167 Soar J, Perkins GD, Maconochie I, et al (2019) European Resuscitation Council Guidelines for Resuscitation: 2018 Update – Antiarrhythmic drugs for cardiac arrest. Resuscitation 134:99–103. https://doi.org/10.1016/j.resuscitation.2018.11.018 Yamreudeewong W, DeBisschop M, Martin LG, Lower DL (2003) Potentially Significant Drug Interactions of Class III Antiarrhythmic Drugs. Drug Safety 26:421–438. https://doi.org/10.2165/00002018-200326060-00004 Kinoshita H, Taniguchi T, Nishiguchi M, et al (2003) An autopsy case of combined drug intoxication involving verapamil, metoprolol and digoxin. Forensic Science International 133:107–112. https://doi.org/10.1016/S0379-0738(03)00056-2 Ha HR, Kozlik P, Stieger B, et al (2001) Metabolism of amiodarone. Journal of Chromatography B: Biomedical Sciences and Applications 757:309–315. https://doi.org/10.1016/S0378-4347(01)00165-7 Maes A, Baert K, Croubels S, et al (2006) Determination of amiodarone and desethylamiodarone in horse plasma and urine by high-performance liquid chromatography combined with UV detection and electrospray ionization mass spectrometry. Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences 836:47–56. https://doi.org/10.1016/j.jchromb.2006.03.038 Bolderman RW, Hermans JJR, Maessen JG (2009) Determination of the class III antiarrhythmic drugs dronedarone and amiodarone, and their principal metabolites in plasma and myocardium by high-performance liquid chromatography and UV-detection. Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences 877:1727–1731. https://doi.org/10.1016/j.jchromb.2009.04.029 Khan MA, Kumar S, Jayachandran J, et al (2005) Validation of a stability indicating LC method for amiodarone HCL and related substances. Chromatographia 61:599–607. https://doi.org/10.1365/s10337-005-0554-3 Al Dhawailie AA (1995) High performance liquid chromatographic determination of amiodarone in plasma and tissues. Analytical Letters 28:2391–2400. https://doi.org/10.1080/00032719508000380 El-Bagary RI, Elkady EF, Mowaka S, Attallah MA (2015) Validated HPLC and ultra-HPLC methods for determination of dronedarone and amiodarone-application for counterfeit drug analysis. Journal of AOAC International 98:1496–1502. https://doi.org/10.5740/jaoacint.15-054 Kuhn J, Götting C, Kleesiek K (2010) Simultaneous measurement of amiodarone and desethylamiodarone in human plasma and serum by stable isotope dilution liquid chromatography-tandem mass spectrometry assay. Journal of Pharmaceutical and Biomedical Analysis 51:210–216. https://doi.org/10.1016/j.jpba.2009.08.004 Riekes MK, Tagliari MP, Granada A, et al (2010) Enhanced solubility and dissolution rate of amiodarone by complexation with β-cyclodextrin through different methods. Materials Science and Engineering C 30:1008–1013. https://doi.org/10.1016/j.msec.2010.05.001 Hasegawa M, Takenaka S, Kuwamura M, et al (2007) Urinary metabolic fingerprinting for amiodarone-induced phospholipidosis in rats using FT-ICR MS. Experimental and Toxicologic Pathology 59:115–120. https://doi.org/10.1016/j.etp.2007.04.001 Liu N, Gao W, Song J-F (2006) Catalytic Adsorptive Stripping Voltammetry at a Carbon Paste Electrode for the Determination of Amiodarone. Chinese Journal of Chemistry 24:1657–1661. https://doi.org/10.1002/cjoc.200690310 Hasanzadeh M, Pournaghi-Azar MH, Shadjou N, Jouyban A (2014) Magnetic nanoparticles incorporated on functionalized mesoporous silica: An advanced electrochemical sensor for simultaneous determination of amiodarone and atenolol. RSC Advances 4:4710–4717. https://doi.org/10.1039/c3ra45433a Banan K, Niknam S, Ahmadi M, et al (2024) Molecularly imprinted electrochemical sensor based on carbon nanofibers for Amiodarone determination. Microchemical Journal 200:. https://doi.org/10.1016/j.microc.2024.110365 Levent A, Önal G (2018) Application of a pencil graphite electrode for voltammetric simultaneous determination of ascorbic acid, norepinephrine, and uric acid in real samples. Turkish Journal of Chemistry 42:460–471. https://doi.org/10.3906/kim-1708-14 Kiliç A, Aslan M, Önal G, Levent A (2023) Firstly electrochemical investigetions and determination of anticoagulant drug edoxaban at single-use pencil graphite electrode: an eco-friendly and cost effective voltammetric method. DARU, Journal of Pharmaceutical Sciences 31:233–241. https://doi.org/10.1007/s40199-023-00478-8 Atay B, Önal G, Levent A (2023) Electrochemical investigations and determination of antineoplastic agent etoposide at single-use pencil graphite electrode: an eco-friendly and cost effective voltammetric method. Monatshefte fur Chemie 154:765–773. https://doi.org/10.1007/s00706-023-03079-y Özer M, Levent A (2024) Application of eco‐friendly disposable pencil graphite sensor for electrochemical evaluation and determination of podophyllotoxin using in cancer treatment. ChemistrySelect 9:. https://doi.org/10.1002/slct.202305100 Annu, Sharma S, Jain R, Raja AN (2020) Review—Pencil Graphite Electrode: An Emerging Sensing Material. Journal of The Electrochemical Society 167:037501. https://doi.org/10.1149/2.0012003jes Hussien EM, Rizk MS, Daoud AM, El-Eryan RT (2022) An Eco-friendly Pencil Graphite Sensor for Voltammetric Analysis of the Antidepressant Vilazodone Hydrochloride. Electroanalysis 34:1402–1410. https://doi.org/10.1002/elan.202100457 Sawkar RR, Patil VB, Shanbhag MM, et al (2021) Detection of ketorolac drug using pencil graphite electrode. Biomedical Engineering Advances 2:100009. https://doi.org/10.1016/j.bea.2021.100009 Ersali H, Levent A (2024) Green Voltammetric Detection of Ophthalmic Drug Nepafenac Using Pencil Graphite Electrode as a Responsive Disposable Electrochemical Sensor. ChemistrySelect 9:. https://doi.org/10.1002/slct.202403549 Wang J (2006) Analytical Electrochemistry. In: Analytical Electrochemistry. Wiley GadelHak Y, Hafez SHM, Mohamed HFM, et al (2023) Nanomaterials-modified disposable electrodes and portable electrochemical systems for heavy metals detection in wastewater streams: A review. Microchemical Journal 193:109043. https://doi.org/10.1016/j.microc.2023.109043 Wang J, Kawde A-N, Sahlin E (2000) Renewable pencil electrodes for highly sensitive stripping potentiometric measurements of DNA and RNA. The Analyst 125:5–7. https://doi.org/10.1039/a907364g Levent A (2017) Voltammetric behavior of acebutolol on pencil graphite electrode: highly sensitive determination in real samples by square-wave anodic stripping voltammetry. Journal of the Iranian Chemical Society 14:2495–2502. https://doi.org/10.1007/s13738-017-1184-z Bard AJ., Faulkner LR. (2001) Electrochemical methods : fundamentals and applications. John Wiley & Sons, Inc. Laviron E, Roullier L, Degrand C (1980) A multilayer model for the study of space distributed redox modified electrodes: Part II. Theory and application of linear potential sweep voltammetry for a simple reaction. Journal of Electroanalytical Chemistry and Interfacial Electrochemistry 112:11–23. https://doi.org/10.1016/S0022-0728(80)80003-9 Laviron E, Roullier L, Degrand C (1980) A multilayer model for the study of space distributed redox modified electrodes. Journal of Electroanalytical Chemistry and Interfacial Electrochemistry 112:11–23. https://doi.org/10.1016/S0022-0728(80)80003-9 Hermosa BG, Kauffmann J-M, Patriarche GJ, Guilbault GG (1986) Electrochemical Behaviour of Benzofuran Derivatives of Pharmaceutical Interest at Solid Electrodes. Analytical Letters 19:2011–2021. https://doi.org/10.1080/00032718608064543 Britton HTS, Robinson RA (1931) CXCVIII.—Universal buffer solutions and the dissociation constant of veronal. J Chem Soc 1456–1462. https://doi.org/10.1039/JR9310001456 Yurdem A, Aslan M, Aral H, Levent A (2024) First electrochemical investigation and determination of non-steroidal anti-inflammatory drug etofenamate using disposable pencil graphite electrode with voltammetric techniques. Analytica Chimica Acta 1299:342377. https://doi.org/10.1016/j.aca.2024.342377 Aslan M, Levent A (2024) Electrochemical investigation of the antimicrobial agent daptomycin utilizing disposable pencil graphite electrode and DNA interaction with green techniques. Microchemical Journal 207:112191. https://doi.org/10.1016/j.microc.2024.112191 Ermer J, McB. Miller JH (2005) Method Validation in Pharmaceutical Analysis. Wiley Additional Declarations No competing interests reported. Supplementary Files SupplementaryInformation18.03.2025.docx floatimage8.jpeg Graphical Abstract Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 01 Apr, 2025 Reviews received at journal 01 Apr, 2025 Reviewers agreed at journal 28 Mar, 2025 Reviewers invited by journal 25 Mar, 2025 Submission checks completed at journal 25 Mar, 2025 First submitted to journal 24 Mar, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-5677107","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":436922940,"identity":"b7f13294-2337-457d-a325-f0bfb89666a4","order_by":0,"name":"Sülbiye DOĞAN","email":"","orcid":"","institution":"Batman University","correspondingAuthor":false,"prefix":"","firstName":"Sülbiye","middleName":"","lastName":"DOĞAN","suffix":""},{"id":436922941,"identity":"111e3074-3072-4db5-bd6c-908a040c9ab4","order_by":1,"name":"Abdulkadir LEVENT","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA7UlEQVRIiWNgGAWjYBACPgiVwMBwmIHxMZjNzNyAVwsbRAdYC7MxA4MBUAsjsVoOMLBJg7UwENLC3mP4uPBHmjzfcd5n1QUVf6L524FaflRsw62F54yx8YyEHMOZh9nNbs84Y5A74zBjA2PPmdu4tUikpUnzJFQwbjjMxnabt80gtwGohZmxDY8W+Wfpv4Fa7EFaikFa5hPUIsF8jJknIScRpIUZpGUDQS08yYeledLSkmceZmOWBnosdyNQy0F8fuFnP9j4mccm2bbv/DHGzzwVcrnzzh8++OBHBW4t2MEBEtWPglEwCkbBKEADAJ/EUYiqZ1P8AAAAAElFTkSuQmCC","orcid":"","institution":"Batman University","correspondingAuthor":true,"prefix":"","firstName":"Abdulkadir","middleName":"","lastName":"LEVENT","suffix":""}],"badges":[],"createdAt":"2024-12-19 13:23:06","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-5677107/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5677107/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":80995378,"identity":"954c940c-0953-421b-8bfe-abd3e30410b6","added_by":"auto","created_at":"2025-04-21 05:03:40","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":381693,"visible":true,"origin":"","legend":"\u003cp\u003eCyclic voltammograms on disposable E-PGE for 0.682 mg/mL AMD in BR (pH 5.0) \u003cstrong\u003e(a)\u003c/strong\u003e Three-cycle voltammogram at a scan rate of 100 mV/s; Dashed line: supporting electrolyte;\u003cstrong\u003e (b)\u003c/strong\u003e Voltammograms of scan rates of 25 mV/s, 50 mV/s, 100 mV/s, 200 mV/s, 300 mV/s, 400 mV/s, and 500 mV/s.\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-5677107/v1/71936088ebad71b85054fd46.png"},{"id":80995254,"identity":"44f92d35-5c47-4ce0-926f-0c9ad21e9d99","added_by":"auto","created_at":"2025-04-21 04:55:40","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":19460,"visible":true,"origin":"","legend":"\u003cp\u003eThe proposed electrochemical mechanism on E-PGE\u003c/p\u003e","description":"","filename":"Onlinefloatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-5677107/v1/0faad38bedcaec87864e5547.png"},{"id":80995373,"identity":"7f181fbf-7919-44dc-aa87-ddb0f869246f","added_by":"auto","created_at":"2025-04-21 05:03:39","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":428794,"visible":true,"origin":"","legend":"\u003cp\u003eSquare-wave curves for 0.136 mg/mL AMD recorded on single-use E-PGE in \u003cstrong\u003e(a)\u003c/strong\u003e BR buffer (pH 2.0–12.0) and \u003cstrong\u003e(b)\u003c/strong\u003e BR (pH 5.0), PBS (pH 2.0, 3.0, and 7.4), CR (pH 4.8) and ABS (pH 4.8) buffers. Accumulation parameters: 0 V/30 s. Square-wave variables: step voltage, 0.004 V; amplitude, 0.03 V; frequency, 60 Hz\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-5677107/v1/ce0a3048e85307fbfbe36296.png"},{"id":80995227,"identity":"32587c45-ae53-4df7-b8e4-1a5b9c502fae","added_by":"auto","created_at":"2025-04-21 04:55:39","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":214587,"visible":true,"origin":"","legend":"\u003cp\u003eSquare-wave voltammograms recorded in BR buffer (pH 5.0) for different concentrations of AMD [\u003cstrong\u003e(1)\u003c/strong\u003e0.125 μg/mL, \u003cstrong\u003e(2)\u003c/strong\u003e 0.624 μg/mL, \u003cstrong\u003e(3)\u003c/strong\u003e 1.248 μg/mL, \u003cstrong\u003e(4)\u003c/strong\u003e 1.872 μg/mL, \u003cstrong\u003e(5)\u003c/strong\u003e2.495 μg/mL, \u003cstrong\u003e(6)\u003c/strong\u003e 3.119 μg/mL, \u003cstrong\u003e(7)\u003c/strong\u003e 3.43 μg/mL, \u003cstrong\u003e(8)\u003c/strong\u003e 4.991 μg/mL, \u003cstrong\u003e(9)\u003c/strong\u003e6.862 μg/mL]. Accumulation parameters: 90 s/+0.4 V. Square wave variables: step voltage, 5 mV; amplitude, 20 mV; frequency, 40 Hz. Dashed line, supporting electrolyte. The calibration curve for AMD is embedded in the figure.\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-5677107/v1/decbcec11e010007f26c20d5.png"},{"id":80995239,"identity":"5f97b658-abdb-4144-9464-898c9b8428af","added_by":"auto","created_at":"2025-04-21 04:55:39","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":1044057,"visible":true,"origin":"","legend":"\u003cp\u003eSquare-wave voltammograms of 6.862 μg/mL AMD recorded in the presence of 68.62 μg/mL (AA, UA, DP, NE, EP, P4, S and TES) solutions in the BR buffer (pH 5.0) on the E-PGE.\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-5677107/v1/e99bafe7773580ae47edb95d.png"},{"id":80995229,"identity":"689a8017-f17b-49e6-b2f2-e414ca539c06","added_by":"auto","created_at":"2025-04-21 04:55:39","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":209711,"visible":true,"origin":"","legend":"\u003cp\u003eSquare-wave voltammograms of \u003cstrong\u003e(1) \u003c/strong\u003ethe diluted samples of Amidovin drug and after standard additions (\u003cstrong\u003e2\u003c/strong\u003e) 0.650 μg/mL, (\u003cstrong\u003e3\u003c/strong\u003e) 1.874 μg/mL, (\u003cstrong\u003e4\u003c/strong\u003e) 3.742 μg/mL, and (\u003cstrong\u003e5\u003c/strong\u003e) 6.353 μg/mL AMD in BR buffer (pH 5.0).Dashed line, supporting electrolyte. The calibration curve for Amidovin drug is embedded in the figure.\u003c/p\u003e","description":"","filename":"floatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-5677107/v1/c754fda0ff6088256426c4f3.png"},{"id":80995234,"identity":"dca740c4-7f4e-4347-9bf9-e0f54204af91","added_by":"auto","created_at":"2025-04-21 04:55:39","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":225529,"visible":true,"origin":"","legend":"\u003cp\u003eSquare-wave voltammograms of AMD in urine samples using the standard addition technique [\u003cstrong\u003e(1) \u003c/strong\u003e0.125 μg/mL, \u003cstrong\u003e(2)\u003c/strong\u003e 0.624 μg/mL, \u003cstrong\u003e(3)\u003c/strong\u003e 1.248 μg/mL, \u003cstrong\u003e(4)\u003c/strong\u003e 1.872 μg/mL, \u003cstrong\u003e(5\u003c/strong\u003e) 2.495 μg/mL, \u003cstrong\u003e(6)\u003c/strong\u003e 3.119 μg/mL, \u003cstrong\u003e(7)\u003c/strong\u003e 4.991 μg/mL] recorded in BR buffer (pH 5.0). Dashed line: supporting electrolyte containing urine only.\u003c/p\u003e","description":"","filename":"floatimage7.png","url":"https://assets-eu.researchsquare.com/files/rs-5677107/v1/2c4397617eb4123519e6ca50.png"},{"id":80995762,"identity":"50c6b11a-9ceb-4aa3-99ea-97e570d36c4c","added_by":"auto","created_at":"2025-04-21 05:12:01","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3877326,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5677107/v1/aaafa2ee-0a82-4322-9604-1c04bf227f0e.pdf"},{"id":80995374,"identity":"3313351b-772d-4048-8638-98cfdf14156b","added_by":"auto","created_at":"2025-04-21 05:03:39","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":3312841,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementaryInformation18.03.2025.docx","url":"https://assets-eu.researchsquare.com/files/rs-5677107/v1/22ef020146bd22d49a150dc6.docx"},{"id":80995228,"identity":"22a1b08a-af73-4c77-9a12-efbf9f4b0238","added_by":"auto","created_at":"2025-04-21 04:55:39","extension":"jpeg","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":704727,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eGraphical Abstract\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"floatimage8.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-5677107/v1/70a3ecfd692ef1d750822435.jpeg"}],"financialInterests":"No competing interests reported.","formattedTitle":"Investigation of electrochemical properties and detection of the antiarrhythmic drug amiodarone in pharmaceutical and urine samples using a disposable pencil graphite electrode","fulltext":[{"header":"Introduction","content":"\u003cp\u003eAmiodarone (AMD, (2-butyl-1-benzofuran-3-yl)-[4-[2-(diethylamino)ethoxy]-3,5-diiodophenyl]methanone) (Figure SI 1) was formulated in the early 1960s as an alternative therapeutic agent for angina pectoris due to its coronary vasodilatory characteristics and ability to decrease myocardial oxygen demand. However, the drug's strong antiarrhythmic effects(prevention of irregular heartbeat) have come to the fore, and its use has been directed accordingly [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. AMD is a class III antiarrhythmic drug commonly used to treat and prevent a variety of irregular heartbeats, including ventricular tachycardia, ventricular fibrillation, and complex tachycardia [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Compared with other antiarrhythmic drugs, AMD was reported to be more effective in the treatment of both supraventricular and ventricular arrhythmias [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Although AMD is an effective drug, its use is complicated by high toxicity, and there are many clinical reports highlighting lung, thyroid, eye, and liver toxicity resulting from drug therapy [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eMeasuring and quantifying the amount of drugs in body fluids and drug samples is important in clinical chemistry, toxicology, doping analysis, and drug research. The therapeutic effect of drugs depends on their concentration in body fluids. However, reliable analytical methods are required to check the pharmaceutical research process, drug discovery, drug development, and drug manufacturing [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. The pharmaceutical analysis involves analytical studies covering various drug development and manufacturing stages. These analytical studies are critical to ensuring that active pharmaceutical ingredients, drug dosage forms, and final pharmaceutical products are safe, effective, and of high quality. Therefore, researchers have used many analytical techniques to determine the concentrations of pharmaceutically important active drug substances.\u003c/p\u003e \u003cp\u003eAccording to our best literature search, some analytical methods were identified for the analysis of AMD in different matrix media: high-performance liquid chromatography [\u003cspan additionalcitationids=\"CR6 CR7 CR8 CR9\" citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e], liquid chromatography-mass spectrometry [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e], Fourier-transform infrared spectroscopy [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e], and Fourier transform ion cyclotron resonance mass spectrometry [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. In addition, electrochemical properties and quantification of AMD were carried out using carbon paste electrode [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e], magnetic (Fe\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e) mobile crystalline material-41 grafted with 3-aminopropyl groups [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e], and molecularly imprinted/carbon nanofibers [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. It appears that the electrodes used for assessing the electrochemical properties and quantifying AMD require modification. Modification of carbon paste electrodes is generally a simple process. However, synthesizing new modification agents may be disadvantageous due to factors such as high cost, requirement for toxic reagents and time-consuming processes.\u003c/p\u003e \u003cp\u003eNo electrochemical method using electrochemical-activated disposable pencil graphite electrodes (E-PGE) for the determination of AMD was found in the literature search. Accordingly, this study was conducted using a disposable E-PGE. The selection of this electrode was based on its advantageous characteristics, including high electrochemical reactivity, well-defined adsorption properties, a wide potential window, excellent mechanical stability, cost-effectiveness, low background current, and ease of modification, making it a highly suitable working electrode for electrochemical applications [\u003cspan additionalcitationids=\"CR18 CR19 CR20 CR21 CR22 CR23 CR24 CR25\" citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. In this study, the analysis of AMD in pharmaceutical and urine samples was successfully performed on disposable E-PGE using a green voltammetric technique, an environmentally friendly approach to electrochemical analysis that minimizes the use of toxic reagents, hazardous solvents, and excessive waste production.\u003c/p\u003e"},{"header":"Material and Methods","content":"\u003cp\u003e\u003cstrong\u003eReagents\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAmiodarone HCl (A8423, Sigma Aldrich), sodium hydroxide (Sigma-Aldrich, reagent grade, \u0026ge;98%, pellets (anhydrous)), hydrochloric acid (Sigma-Aldrich, 37%, ACS reagent), potassium hexacyanoferrate(III)hydrochloric acid (Sigma-Aldrich, ACS reagent, \u0026ge;99.0%), potassium hexacyanoferrate(II) trihydrate (Sigma-Aldrich, ACS reagent, 98.5-102.0%), citric acid (Sigma-Aldrich, ACS reagent, \u0026ge;99.5%), sodium citrate (Sigma-Aldrich, pharmaceutical secondary standard), glacial acetic acid (Sigma-Aldrich, glacial, ACS reagent, \u0026ge;99.7%), phosphoric acid (Sigma-Aldrich, ACS reagent, \u0026ge;85 wt. % in H2O), boric acid (Sigma-Aldrich, ACS reagent, \u0026ge;99.5%), di-Sodium hydrogen phosphate dihydrate (Sigma-Aldrich, buffer substance for chromatography LiChropur\u0026trade;) and ethanol (Sigma Aldrich, \u0026ge;99.9% (GC), gradient grade, suitable for HPLC, gradient grade, LiChrosolv\u0026reg;) were used in this study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eInstruments\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAutolab PGSTAT128N was used as the electrochemical analyzer in the experiments. Disposable pencil lead (Tombo 0.5/2B Japan) was used as the working electrode, an Ag/AgCl (3 M NaCl) (MF 1063; BASi) as the reference electrode, and a platinum wire (MF 1032, BASi) as the auxiliary electrode. The experiments were performed in a 10 mL 3-compartment capped standard glass cell (MR1208, BASi). ARE heating magnetic stirrers, and magnetic stir bars (Spinbar VMR) were used to mix the solutions. A Thermo Scientific Orion 3 Star pH meter was used for pH measurements and a Precisa 320XB 220A precision balance for accurate weighing. The Shimadzu 1900 spectrophotometer was used to obtain the UV-Vis spectrum, and the ZEISS-LEO 1430 SEM devices were used.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePreparation of solutions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAMD HCl stock solution was prepared in ethanol at 3.41 mg/mL. Voltammetric experiments were carried out in different supporting electrolytes. For this purpose, various buffer solutions such as 0.1 mol/L acetate (ABS) pH=4.8, 0.1 mol/L citrate (CR) pH=4.8, 0.04 mol/L Britton-Robinson (BR) between pH 2.0 and pH 11.0, and 0.1 mol/L phosphate (PBS) pH=2.0, pH=3.0, and pH=7.4 were used. The pHs of these solutions were adjusted with 0.5 mol/L NaOH or 0.5 mol/L HCl solutions. The buffer solutions were stored in a refrigerator in Pyrex\u0026reg; glass bottles when not in use.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eVoltammetric measurements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIn the voltammetic analysis studies, the triple electrode system of BASi Company was used. For single-use PGE, a 0.5 Rotring T 0.5 tipped pen and the pen tips required for this (Model, Tombow 0.5/2B Japan) were commercially obtained from a stationery. These tips were cut to a length of 30 mm and placed in the tipped pen, leaving 15 mm of the tip outside. The conductivity between the pen tip and the potentiostat was provided by copper wire. This PGE was electrochemically activated for 60 s at +1.4 V potential in the selected supporting electrolyte solution before the electrochemical measurements [27, 28]. This type of activation was done to obtain uniform and more repeatable signals. Experiments were performed using a new pen tip for each analysis. After PGE was electrochemically activated in the selected supporting electrolyte medium, cyclic voltammetry, square-wave, and differential pulse experiments were performed in the range of 0 V to +1.45 V. Experiments were carried out to optimize the deposition potential (0 V- 0.7 V) and deposition time (0 s \u0026ndash; 150 s) for the adsorptive anodic signal of AMD on the E-PGE surface. In addition, optimization studies were carried out for step potential (1 mV- 9 mV), modulation amplitude (10 mV- 80 mV) and frequency (10 Hz-90 Hz) values within the scope of optimization of square-wave voltammetry parameters. Under these optimum conditions determined for AMD, the square-wave voltammetry technique was used for analysis in pharmaceutical and urine samples.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePreparation of real samples\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAmidovin (150 mg/3 mL, T\u0026uuml;m Ekip Pharmaceuticals Inc., İstanbul) ampoules were purchased from pharmacies in Turkey for analytical applications. Firstly, an aliquot 10 \u0026micro;L of Amidovin sample was taken, and diluted with BR (pH 5.0) supporting electrolyte solution to make a total volume of 10 mL. Then, 100 \u0026micro;L of this solution was added to the electrochemical cell containing 10 mL of supporting electrolyte, and the mixture was vigorously stirred. After this, SWV experiments were performed without any sample pretreatment. The voltammetric procedure described in the section \u003cstrong\u003e(voltammetric measurements)\u003c/strong\u003e was applied and the voltammograms for the ampoule solutions were recorded. Then, the standard addition method was applied to the electrolyte in a similar manner to construct the recovery curves before fortification (artificial contamination) and without fortification. Recovery curves were performed in triplicate, and mean recovery values were calculated using the same methodology effectuated in the pure electrolyte. The amount of AMD in the Amidovin ampoule and recovery studies were performed using the multiple standard addition method.\u003c/p\u003e\n\u003cp\u003eA urine sample was collected from a healthy volunteer immediately prior to the experiments with the approval from the Batman University Non-Interventional Clinical Research Ethics Committee (27.02.2024-E.153368). For analysis, 5 mL of urine sample was added to each of two 10 mL test tubes. One test tube was diluted with BR buffer (pH 5.0), and the voltammogram of this sample was recorded (Figure 7). The other test tube contained urine, BR buffer, and a final concentration of 0.125 \u0026mu;g/mL of AMD. Then, AMD additions were made to the final solutions in the range of 0.624 \u0026mu;g/mL to 4.991 \u0026mu;g/mL, and % recovery calculations were made (Table 3). In order to ensure homogeneity and interaction in these samples, the samples were mixed for 5 minutes at 3000 rpm using an IKA MS 3 Basic Vortex Tube Mixer. The urine samples were analyzed using the voltammetric procedure as described in the section \u003cstrong\u003e(voltammetric measurements),\u0026nbsp;\u003c/strong\u003eand their voltammograms were recorded. The analysis of AMD in urine samples and recovery studies was performed using the multiple standard addition method.\u003c/p\u003e"},{"header":"Results and Discussion","content":"\u003cp\u003e\u003cstrong\u003eElectrochemical activation of PGE\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIn this study, in order to obtain more sensitive, responsive, and reproducible signals on the PGE surface, electrochemical activation of PGE was carried out in the supported electrolyte medium. The characterization of bare PGE and E- PGE was investigated in detail using cyclic voltammetry, electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM) techniques. Here, EIS analyzes the behavior of the electrode-electrolyte interface by determining parameters such as charge transfer resistances, double layer capacitance, and diffusion processes occurring on the electrode surface. Thus, it provides important information in many areas, such as material characterization, evaluation of electrode modifications, and elucidation of reaction mechanisms [29]. Cyclic voltammetry (100 mV/s voltage scan rate) and EIS (at a sinusoidal potential of +0.25 V, and conducted between 100 mHz and 0.1 Hz) measurements were performed on the redox probe 2.5 mol/L ([Fe(CN)\u003csub\u003e6\u003c/sub\u003e]\u003csup\u003e4-/3-\u003c/sup\u003e) containing 0.1 mol/L KCl. The surface areas of bare PGE and E-PGE electrodes were determined by recording the cyclic voltammograms in a 0.1 mol/L supporting electrolyte solution containing 2.5 mmol/L of a redox probe. The anodic peak current values obtained from the cyclic voltammograms were used to calculate the effective surface areas of bare PGE and E-PGE using the Randles-Sevcik equation [29] [ ], where \u003cem\u003en\u003c/em\u003e represents the number of electrons transferred during the electrode reaction, taken as 1 for the redox probe. \u003cem\u003eD\u003c/em\u003e denotes the diffusion coefficient of the redox probe, with a value of 7.6\u0026times;10⁻⁶ cm\u0026sup2;/s. \u003cem\u003ev\u003c/em\u003e is the scan rate (V/s), \u003cem\u003eC\u003c/em\u003e is the concentration of the redox probe, and \u003cem\u003eA\u003c/em\u003e represents the effective surface area of the electrodes. The calculated effective surface areas were 0.009 cm\u0026sup2; for bare PGE and 0.011 cm\u0026sup2; for E-PGE. Moreover, the cyclic voltammetry results given in Figure SI 2a show that E-PGE exhibits higher current density compared to bare PGE. This indicates that electrochemical activation increases the electrode surface area, strengthens the interaction with the redox probe, and improves the electron transfer kinetics. The potential difference between the anode and cathode current peaks for bare PGE and E-PGE was found to be 0.56 V and 0.25 V, respectively. As a result, the decrease in the potential difference between the anode and cathode current peaks of E-PGE supports a faster and more efficient electron transfer mechanism. The EIS results presented in Figure SI 2b quantitatively reveal the difference between the electrochemical properties of bare PGE and E-PGE. Here, the charge transfer resistances (Rct) for bare PGE and E-PGE were found to be 8950 \u0026Omega; and 2105 \u0026Omega;, respectively. According to the Nyquist diagram, bare PGE has a larger semicircle, indicating a higher Rct. In contrast, the smaller semicircle in E-PGE confirms that Rct decreases and the electron transfer kinetics at the electrode surface accelerates. When the EIS data are analyzed in accordance with the equivalent circuit model (Figure 2b, inset), it is seen that E-PGE presents a more advantageous structure electrochemically with a lower Rct value. These findings reveal that electrochemical activation causes significant structural and electronic changes on the PGE surface, making the electrode more sensitive to the redox probe.\u003c/p\u003e\n\u003cp\u003eFigure SI 3 shows the images of bare PGE (a) and E-PGE (b) surfaces obtained by SEM. When the images are analysed, it is observed that the bare PGE surface is relatively smooth and has low porosity (Figure SI 3a). This structure indicates that the electrode surface offers a limited active area and is not sufficiently favourable for electron transfer processes. In contrast, the E-PGE surface obtained after electrochemical activation (Figure SI 3b) exhibits significant morphological changes. As a result of the activation process, a more porous, rough, and heterogeneous structure was observed on the surface. This change leads to an increase in the electrode surface area and provides more active sites for electrochemical reactions. Moreover, the particle formations and crack-like structures observed on the surface are thought to improve the electrochemical performance by reducing the charge transfer resistance. These results show that the electrochemical activation process leads to significant structural changes on the surface of the PGE, as directly observed by SEM. Additionally, cyclic voltammetry and EIS provide indirect evidence of these electrochemical activation process, demonstrating the improved electrochemical properties of the electrode and resulting in a more efficient electrode surface.\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCyclic voltammetry results of amiodarone on E-PGE\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIn this part of the study, cyclic voltammetry analysis was performed using a 0.682 mg/mL of AMD in BR (pH 5.0) buffer with disposable E-PGE. This analysis was performed in the voltage range from 0 V to +1.5 V and at a scanning speed of 100 mV/s. Figure 1a shows a three-cycle voltammogram of AMD in BR (pH 5.0) buffer. When these voltammograms were examined, an oxidation wave occurred at approximately +0.94 V potential. Based on the increase in the number of cycles, there was a decrease in the anodic peak signal intensity and this voltammogram wave became more widespread. The decline in anodic peak current suggests progressive changes at the electrode surface, such as passivation, fouling, or material degradation, which hinder the redox reaction efficiency over multiple cycles.\u003c/p\u003e\n\u003cp\u003eFigure 1b presents the cyclic voltammetry results obtained for a 0.682 mg/mL AMD solution in BR buffer (pH 5.0) over a scan rate range of 25 mV/s to 500 mV/s. The oxidation peak potential exhibited a shift towards more positive values as the scan rate increased. In this process, corresponding to voltage scanning rates of 25 mV/s, 50 mV/s, 100 mV/s, 200 mV/s, 300 mV/s, 400 mV/s, and 500 mV/s, respectively, +0.921 V, +0.932 V, +0.954 V, +0.965 V, +0.971 V, +0.984 V and +1.013 V values were observed. To investigate the underlying electrochemical processes governing AMD oxidation on E-PGE, the relationship between the anodic peak current and potential with respect to scan rate variations was analyzed. These findings suggest that the electrochemical behavior of AMD on E-PGE is influenced by the scan rate under the given experimental conditions. Specifically, at lower scan rates, the oxidation peak potential appeared at more negative values, whereas at higher scan rates, a shift towards more positive potentials was observed. This behavior provides insights into the possible involvement of adsorption, diffusion, and electron transfer phenomena in the electrochemical mechanism of AMD oxidation [29].\u003c/p\u003e\n\u003cp\u003eBy evaluating the data in the voltammograms recorded in Figure 1b and Figure SI 4, the Ip/\u0026radic;\u003cem\u003ev\u003c/em\u003e relationship [Ip (\u0026micro;A) =0.370\u0026radic;\u003cem\u003ev\u003c/em\u003e + 0.335, r =0.99] (Figure SI 4a), the Ip/\u003cem\u003ev\u003c/em\u003e relationship [Ip(\u0026micro;A) = 0.54\u003cem\u003ev\u003c/em\u003e +12.61, r = 0.91] (Figure SI 3b), and the logIp/log\u003cem\u003ev\u003c/em\u003e relationship [logIp (\u0026micro;A) = 0.78log\u003cem\u003ev\u003c/em\u003e + 0.89, r = 0.97] (Figure SI 4c) were calculated. In the case of adsorption-controlled behavior, the slope of the logIp/logv graph is ideally found to be 1. In such a case, Ip also changes linearly, proportional to \u003cem\u003ev\u0026nbsp;\u003c/em\u003e[30]. If diffusion-induced adsorption is the case, the slope value obtained for the equation between logIp and log\u003cem\u003ev\u003c/em\u003e will be between 0.5 and 1. On the other hand, in a completely diffusion-controlled process, the slope value will be 0.5. In this study, there was a linear change between Ip and \u0026radic;\u003cem\u003ev\u003c/em\u003e, and the slope of the equation between logIp and logv was between 0.5 and 1 (logIp(\u0026micro;A) = 0.78log\u003cem\u003ev\u003c/em\u003e + 0.89, \u003cem\u003er =\u003c/em\u003e 0.97). When these findings are taken together, the electrochemical process on the disposable PGE surface may be diffusion-induced adsorption. As seen in Figure 1b, the anodic peak voltages shift to a more positive region in the range of 25-500 mV/s scan speeds. This phenomenon indicates an irreversible electrochemical reaction mechanism.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe relationship between the anodic peak potential (Ep) and the scan rate (\u003cem\u003ev\u003c/em\u003e) is expressed by the following equation: Ep =E\u003csup\u003e0\u003c/sup\u003e + (2.303RT / \u0026alpha;nF) log (RT\u003cem\u003ek\u003c/em\u003e / \u0026alpha;nF) + (2.303RT / \u0026alpha;nF) log \u003cem\u003ev\u0026nbsp;\u003c/em\u003e[31]. In this equation, E\u003csup\u003e0\u003c/sup\u003e represents the standard electrode potential, \u003cem\u003ek\u0026nbsp;\u003c/em\u003erepresents the heterogeneous electron transfer rate constant,\u003cem\u003e\u0026nbsp;\u0026alpha;\u003c/em\u003e represents the charge transfer coefficient and \u003cem\u003en\u003c/em\u003e represents the number of electrons transferred in the redox reaction. The constants are the gas constant (R = 8.314 J K\u003csup\u003e/\u003c/sup\u003emol), temperature (T = 298 K), charge transfer coefficient (\u0026alpha;= 0.5), and Faraday constant (F = 96485.33 C/mol). The Ep - log\u003cem\u003ev\u003c/em\u003e linear relationship obtained on the PGE surface under optimum operating conditions is determined as follows: Ep(V)=0.061 log\u0026nu; (mV/s) + 0.742. Based on this relationship, the slope value is calculated as 0.061. As a result of the relevant calculations, the number of transferred electrons is found as n = 1.94 and is accepted as approximately 2.\u003c/p\u003e\n\u003cp\u003eIn light of this information, the possible electrochemical mechanism occurring on E-PGE may be as follows (Figure 2). When 1 e\u003csup\u003e-\u003c/sup\u003e is removed from the AMD compound, radical carbocation is formed on the furan ring [32]. In this process, this radical loses another 1 e\u003csup\u003e-\u0026nbsp;\u003c/sup\u003eand di-carbocation is formed. In this structure, one of these carbocations is mesomerically stable due to the effect of the neighboring group since it is adjacent to the oxygen atom, while the other carbocation is mesomerically stable by the aromatic ring since it is in the aryl position. Following the attachment of the water molecule to these positively charged carbons, a diol is formed by removing one H\u003csup\u003e+\u003c/sup\u003e from each.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eImpact of supporting electrolyte and pH\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIn electrochemical analysis, the selection of the supporting electrolyte composition and pH is of great importance in evaluating the electrochemical behavior of the substance on the electrode surface [28]. These selections have a significant effect on the accuracy, sensitivity, and reliability of the analysis by affecting the redox properties of the analyte compound. While BR is a multi-purpose buffer solution covering a wide pH range [33], ABS, CR, and PBS buffers are also effective solutions at certain pH [34].\u003c/p\u003e\n\u003cp\u003eBased on this information, in this part of our investigation, 0.04 mol/L BR buffer (Figure 3a) with a pH range of 2.0-12.0, 0.1 mol/L PBS (pH 2.0, 3.0, 7.4), 0.1 mol/L CR (pH, 4.8), and 0.1 mol/L ABS (pH 4.8) buffers (Figure 3b) were used to record voltammograms from 0.136 mg/mL AMD on single-use E-PGE with the square-wave voltammetric technique. When Figures 3a and 3b are reviewed in depth, the most appropriate supporting electrolyte is BR, with a pH of 5.0. In addition, as can be seen in the experiments carried out on different types of supporting electrolytes, it was clearly determined that the anodic signal intensity of AMD around pH = 5 (\u0026plusmn;1) was higher (Figure 3b). As the pH of all supporting electrolytes increases, the anodic peak potential value moves to the more negative area. These results were found to be compatible with the literature [32]. When the data presented in Figure 3 is evaluated, significant changes in the Ep and peak current are observed depending on the pH change. This clearly shows that the electrochemical process occurring on the E-PGE surface progresses with the contribution of protons. The change of the anodic peak potential with pH is expressed with a linear relationship, and the obtained equation is as follows: Ep(V)= -0.052 pH + 4.13 (Figure SI 5). Based on this relationship, it can be said that proton and electron transfers occur at equal rates in the electrochemical process occurring on the E-PGE surface of AMD under operating conditions.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSelection of voltammetric technique\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTo perform the analysis of AMD in pharmaceutical and urine samples more sensitively and precisely, square-wave and differential pulse voltammetry techniques were used on the E-PGE surface. For this purpose, voltammetric experiments were carried out in BR (pH 5.0) medium. As can be seen in Figure SI 6, the anodic signal intensity of AMD was 45% higher when the square-wave technique was used. Thus, in the following sections of the analytical study, unless otherwise stated, the square-wave voltammetry technique will be used as the voltammetric technique.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eInfluence of deposition and square-wave parameters on electrode response\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIn this part of the study, the effect of deposition voltage and time on the electrode response were investigated to achieve more sensitive and reproducible signals on E-PGE. Measurements were performed using 0.102 mg/mL AMD in BR buffer (pH 5.0) with 60 s accumulation time in the voltage range of 0 V to +0.7 V. The highest peak current was recorded at +0.4 V (Figure SI 7a). Therefore, in the continuation of the study, +0.4 V deposition voltage was applied on E-PGE, and voltammograms were recorded at deposition times ranging from 0 s to 150 s (Figure SI 7b). The anodic peak current intensity increased rapidly up to 90 s and then decreased significantly. The anodic peak current intensity exhibited a rapid increase up to 90 seconds, reaching its maximum value, after which it significantly decreased. This behavior suggests an initial accumulation of electroactive species on the electrode surface, followed by a decline possibly due to surface saturation, desorption effects, or diffusion limitations.\u003c/p\u003e\n\u003cp\u003eAlong with the analytical investigation, optimization experiments for the device settings employed in the square-wave voltammetry technique were thoroughly investigated in order to obtain the most sensitive and symmetric voltammograms on E-PGE [35]. In this way, experiments were performed with frequency (10 Hz -90 Hz), step voltage (1 mV-9 mV), and amplitude (10 mV-80 mV) as square-wave parameters. These experiments were carried out in the BR (pH 5.0) supporting electrolyte solution containing 0.102 mg/mL AMD. During the measurements, the influence of each parameter was investigated while the values of the other two parameters remained constant. Under constant amplitude and frequency settings, raising the step potential to 5 mV enhanced in peak intensity (Figure SI 8a). Nevertheless, it was noted that for step potential values greater than 5mV, the anodic peak flattened, and the residual current showed notable aberrations. A notable rise in anodic signal intensity was noted when the amplitude value was raised to 20 mV while maintaining a consistent step voltage and frequency (Figure SI 8b). When the amplitude values were above 20 mV, peak signal strength decreased. Finally, it was determined that with constant amplitude and step potential, the peak signal intensity increased with frequency up to 40 Hz, but decreased at higher values (Figure SI 8c). In this research, 90 s accumulation time, +0.4 V accumulation voltage, 5 mV step voltage, 20 mV amplitude, and 40 Hz frequency were accepted as the optimum values unless otherwise stated in the continuation of the analytical study.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAnalytical linear working range\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis section of the study focused on assessing the voltammetric approach utilizing E-PGE for the detection of AMD in urine and pharmaceutical samples, specifically evaluating its analytical working range, and reproducibility. Using the standard stock solution of 3.41 mg/mL AMD prepared in ethanol under optimum operating conditions, voltammograms were recorded by making known additions to the electrochemical cell (Figure 4). As can be seen in Figure 4, the anodic peak at +0.94 V was evaluated after each successive addition of the standard AMD solution. This anodic peak showed very good linearity [Ip(\u0026mu;A)=0.113 C(\u0026mu;g/mL) +0.039 (\u003cem\u003er\u0026nbsp;\u003c/em\u003e=0.998, \u003cem\u003en\u003c/em\u003e=9)] on E-PGE in the concentration range from 0.125 \u0026mu;g/mL to 6.862 \u0026mu;g/mL. From these data, the limit of detection (LOD = 3 s/m) and limit of quantification (LOQ = 10 s/m) were calculated [36]: In these equations, \u003cstrong\u003e\u003cem\u003es\u003c/em\u003e\u003c/strong\u003e represents the standard deviation of the peak current (as the average of 3 values) corresponding to the lowest concentration in the linearity range, while \u003cstrong\u003e\u003cem\u003em\u003c/em\u003e\u003c/strong\u003e represents the slope of the relevant calibration equation. Using the data here, the LOD value was found to be 0.027 \u0026mu;g/mL, and the LOQ value was found to be 0.089 \u0026mu;g/mL. The voltammetric method developed using single-use E-PGE for the analysis of AMD in different environments was compared with the analytical methods presented in Table 1 in terms of LOD values. As can be seen from these results, the LOD value of 0.027 \u0026mu;g/mL obtained with single-use PGE is very good. The E-PGE used in the square-wave voltammetric technique is more cost-effective than complex electrode materials (e.g., Fe₂O₃-MCM-41-nPrNH₂-CPE) used in other methods [15, 16], making it economically advantageous option. The E-PGE electrodes used in the method stand out as an environmentally friendly alternative since they do not contain expensive or toxic reagents. Compared to HPLC [6\u0026ndash;8, 10, 11], which requires high organic solvent consumption, this method uses fewer chemicals. At the same time, the general advantages of electrochemical methods, fast analysis time and simple device requirements are quite advantageous compared to chromatographic methods.\u003c/p\u003e\n\u003cp\u003eIn order to test the repeatability level of the single-use E-PGE chosen as the working electrode, 2.495 \u0026mu;g/mL AMD solution was prepared. Under optimum experimental conditions, square-wave voltammograms of this AMD solution were recorded nine times on the same day using E-PGE. The oxidation peak current and voltage data from these recorded voltammograms were used for computations. Thus, the RSD value for the oxidation peak current was 3.84% (3.62 % RSD), and the oxidation voltage value was 0.42% (3.34 % RSD).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 1.\u003c/strong\u003e Analytical performance of analytical techniques proposed for the analysis of AMD in different matrix media\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"614\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eTechnique\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eElectrode/Detector\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eLinear concentration range (\u0026mu;g/mL)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eLOD (\u0026mu;g/mL)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 113px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMatrix\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eReference\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003eHPLC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003eUV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e0-0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e0.015\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 113px;\"\u003e\n \u003cp\u003eHorse Plasma\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003e[6]\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003eHPLC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003eUV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e0.01-5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e0.01\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 113px;\"\u003e\n \u003cp\u003ePlasma\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003e[7]\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003eRP-HPLC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003eUV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e5-80\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e1.49\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 113px;\"\u003e\n \u003cp\u003ePharmaceutical\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003e[10]\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003eHPLC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003eUV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e0.25-10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e0.125\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 113px;\"\u003e\n \u003cp\u003ePharmaceutical\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003e[8]\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003eLC-MS/MS\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003eUV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e0.01\u0026ndash;40.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e2700\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 113px;\"\u003e\n \u003cp\u003ePlasma\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003e[11]\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003eASV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003eCPE\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e0.0014-0.016\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e0.0001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 113px;\"\u003e\n \u003cp\u003ePharmaceutical\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003e[14]\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003eDPV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003eFe\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e\u0026ndash;MCM-41\u0026ndash;nPrNH\u003csub\u003e2\u003c/sub\u003e-CPE\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e3.07-484.08\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e1.43\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 113px;\"\u003e\n \u003cp\u003ePharmaceutical\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003e[15]\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003eCV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003eMIP/CNF\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e2-10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e0.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 113px;\"\u003e\n \u003cp\u003ePlasma\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003e[16]\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003eSWV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003eE-PGE\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e0.125-6.862\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e0.027\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 113px;\"\u003e\n \u003cp\u003ePharmaceutical, Urine\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 76px;\"\u003e\n \u003cp\u003eThis work\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eHPLC: High-performance liquid chromatography; RP-HPLC: Reversed-phase high-performance liquid chromatography; LC-MS/MS: Liquid chromatography-mass spectrometry/mass spectrometry; UV: Ultraviolet detector; ASV: Adsorptive stripping voltammetry; CPE: Carbon paste electrode; DPV: Differential pulse voltammetry; Fe₂O₃\u0026ndash;MCM-41\u0026ndash;nPrNH₂: mobile crystalline material-41-nPrNH₂-modified electrode; CV: Cyclic voltammetry; MIP/CNF: Molecularly imprinted polymer-modified carbon nanofiber electrode; SWV: Square-wave voltammetry; E-PGE; Electrochemical-activated disposable pencil graphite electrodes.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSelectivity of the voltammetric method\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIn the present study, the interference effects of ascorbic acid (AA), uric acid (UA), dopamine (DP), norepinephrine (NE), epinephrine (EP), progesterone (P4), sucrose (S), testosterone (TES) and some inorganic substances (Fe\u003csup\u003e2+\u003c/sup\u003e, Cu\u003csup\u003e2+\u003c/sup\u003e, Zn\u003csup\u003e2+\u003c/sup\u003e, Co\u003csup\u003e2+\u003c/sup\u003e, Ni\u003csup\u003e2+\u003c/sup\u003e, NO\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e-\u003c/sup\u003e, Cl\u003csup\u003e-\u003c/sup\u003e, and SO\u003csub\u003e4\u003c/sub\u003e\u003csup\u003e2-\u003c/sup\u003e), which may be present in biological fluids, on the voltammetric measurement of AMD were investigated. The AMD concentration was kept at 6.862 \u0026mu;g/mL, whereas the concentration of potentially interfering solutions was 10, 50, and 100 times higher. Figure 5 shows the voltammograms acquired from the measurements for the organic substances. As seen from the recorded voltammograms, it was determined that the tested analytes were not oxidized in the voltage range where AMD was oxidized on the E-PGE surface under these operating conditions. Additionally, it was determined that these analytes did not alter the anodic peak current signal intensity of AMD beyond \u0026plusmn;5%. These findings demonstrate that the amount of AMD in bodily fluids may be consistently determined on E-PGE under these experimental settings. These particular interference investigations provide critical and significant information for the therapeutic use of these medications.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eApplication to real samples\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIn this part of the study, the applicability of the voltammetric method developed on disposable E-PGE was tested for pharmaceutical and urine samples. Amidovin (150 mg/3 mL, T\u0026uuml;m Ekip Pharmaceuticals Inc., İstanbul) ampoules supplied by pharmacies in Turkey were chosen for the pharmaceutical sample application. Quantification and recovery studies were carried out by applying the experimental protocols in the section (\u003cstrong\u003epreparation of real samples\u003c/strong\u003e). First, the square-wave voltammogram was recorded in 100 \u0026micro;L of Amivodin 10 mL of BR (pH 5.0) supporting electrolyte solution (Figure 6). We observed the anodic signal of standard AMD at\u0026nbsp;+0.94 V. After this, when standard AMD (concentrations in the final solution, 0.652 \u0026mu;g/mL, 1.875 \u0026mu;g/mL, 3.743 \u0026mu;g/mL, and 6.354 \u0026mu;g/mL) was successfully added to this solution, the anodic peak signal of AMD increased linearly [Ip(\u0026mu;A)=0.103 C(\u0026mu;g/mL) +0.052 (r =0.989, n=5)]. The obtained results are presented in Table 2. The average of these results, AMD was measured as 152 mg / 3 mL with 102.25 % (4.25 % RSD) recovery in the Amidovin ampoule, which is very close to the 150 mg / 3 mL Amiodarone HCl level declared by the commercial company for each ampoule. This result shows that AMD can be analyzed with high accuracy in pharmaceutical samples using disposable E-PGE under optimum working conditions. In addition, to test the accuracy of the voltammetric technique developed on E-PGE, a spectrophotometric technique was used for the analysis of AMD in pharmaceutical samples. For this purpose, UV-visible spectra of AMD were recorded in the wavelength range of 200 nm to 800 nm (Figure SI 9). It was observed that AMD had maximum absorbance at 244 nm. At this wavelength, AMD gave a linear change of A(Au)=0.083 C\u003csub\u003e[AMD]\u003c/sub\u003e(\u0026mu;g/mL) -0.268, r=0.996 in the concentration range from 1.44 \u0026micro;g/mL to 10.06 \u0026micro;g/mL. Using the analytical calibration curve, AMD in the Amidovine ampoule was found to be 145.87 mg / 3 mL with 97.25 % (3.12 % RSD) recovery. It was observed that the results obtained by both techniques were consistent with each other.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 2\u003c/strong\u003e. Square-wave voltammetric method analysis of Amidovin drug spiked with AMD standard solutions using E-PGE.\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 175px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAdded\u003csup\u003ea\u003c/sup\u003e (\u0026micro;g/mL)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 192px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eDetected\u003csup\u003ea,b\u003c/sup\u003e (\u0026micro;g/mL)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eRecovery%\u003csup\u003ec\u003c/sup\u003e\u0026plusmn;RSD%\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 175px;\"\u003e\n \u003cp\u003e0.498\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 192px;\"\u003e\n \u003cp\u003e0.505\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003e101.41 \u0026plusmn; 4.25\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 175px;\"\u003e\n \u003cp\u003e0.650\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 192px;\"\u003e\n \u003cp\u003e0.628\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003e96.61 \u003cstrong\u003e\u0026plusmn;\u0026nbsp;\u003c/strong\u003e4.02\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 175px;\"\u003e\n \u003cp\u003e1.874\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 192px;\"\u003e\n \u003cp\u003e1.955\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003e104.32 \u003cstrong\u003e\u0026plusmn;\u0026nbsp;\u003c/strong\u003e3.95\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 175px;\"\u003e\n \u003cp\u003e3.742\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 192px;\"\u003e\n \u003cp\u003e3.931\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003e105.05 \u003cstrong\u003e\u0026plusmn;\u0026nbsp;\u003c/strong\u003e4.18\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 175px;\"\u003e\n \u003cp\u003e6.353\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 192px;\"\u003e\n \u003cp\u003e6.603\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003e103.93 \u003cstrong\u003e\u0026plusmn;\u0026nbsp;\u003c/strong\u003e3.72\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003csup\u003ea\u003c/sup\u003eFinal concentration of AMD spiked into Amidovin drug in BR (pH 5.0) supporting electrolyte medium.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003csup\u003eb\u003c/sup\u003eValues are the average of three independent analysis.\u003c/p\u003e\n\u003cp\u003e\u003csup\u003ec\u003c/sup\u003eRecovery%:(detected/added)x100\u003c/p\u003e\n\u003cp\u003eThe analysis of AMD in urine samples containing complex matrix was carried out by following the experimental protocol in the section (\u003cstrong\u003epreparation of real samples)\u003c/strong\u003e. Here, firstly, the voltammogram of the urine sample in BR (pH 5.0) buffer solution medium was recorded (Figure 7). Under these study conditions, when only diluted\u0026nbsp;urine sample was used, no signal was observed on E-PGE that could interfere with the anodic signal of AMD. This result shows that AMD can be analyzed safely in urine samples. For the second analysis, square-wave voltammograms were recorded after diluting 250 \u0026micro;L of AMD-containing urine sample with 10 mL of BR (pH 5.0) supporting electrolyte solution. Square-wave voltammograms were recorded by adding AMD with final concentrations ranging from 0.125 \u0026mu;g/mL to 4.991 \u0026mu;g/mL using the standard addition technique. The anodic peak of AMD observed at +0.94 V on disposable E-PGE increased in direct proportion to the amount of standard AMD added to urine samples. Here, with the addition of AMD, a good linearity was obtained between the anodic peak current and concentration. [Ip(\u0026mu;A)=0.148 C\u003csub\u003e[AMD]\u003c/sub\u003e(\u0026mu;g/mL) -0.103 (\u003cem\u003er\u003c/em\u003e =0.987]. The results obtained are summarised in Table 3. According to these results, it was shown that AMD can be successfully analysed in urine samples with an average recovery of 99.46% (4.08% RSD).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 3\u003c/strong\u003e. Square-wave voltammetric method analysis of urine samples spiked with AMD standard solutions using E-PGE.\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 175px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAdded\u003csup\u003ea\u003c/sup\u003e (\u0026micro;g/mL)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 192px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eDetection\u003csup\u003ea,b\u003c/sup\u003e (\u0026micro;g/mL)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eRecovery%\u003csup\u003ec\u003c/sup\u003e\u0026plusmn;RSD%\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 175px;\"\u003e\n \u003cp\u003e0.125\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 192px;\"\u003e\n \u003cp\u003e0.117\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003e93.60 \u0026plusmn; 4.12\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 175px;\"\u003e\n \u003cp\u003e0.624\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 192px;\"\u003e\n \u003cp\u003e0.608\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003e97.44 \u003cstrong\u003e\u0026plusmn;\u0026nbsp;\u003c/strong\u003e4.32\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 175px;\"\u003e\n \u003cp\u003e1.248\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 192px;\"\u003e\n \u003cp\u003e1.314\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003e105.29 \u003cstrong\u003e\u0026plusmn;\u0026nbsp;\u003c/strong\u003e4.19\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 175px;\"\u003e\n \u003cp\u003e1.872\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 192px;\"\u003e\n \u003cp\u003e1.781\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003e95.14 \u003cstrong\u003e\u0026plusmn;\u0026nbsp;\u003c/strong\u003e3.78\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 175px;\"\u003e\n \u003cp\u003e2.495\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 192px;\"\u003e\n \u003cp\u003e2.409\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003e96.55 \u003cstrong\u003e\u0026plusmn;\u0026nbsp;\u003c/strong\u003e3.98\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 175px;\"\u003e\n \u003cp\u003e3.119\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 192px;\"\u003e\n \u003cp\u003e3.229\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003e103.53 \u003cstrong\u003e\u0026plusmn;\u0026nbsp;\u003c/strong\u003e4.28\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 175px;\"\u003e\n \u003cp\u003e4.991\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 192px;\"\u003e\n \u003cp\u003e5.228\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003e104.75 \u003cstrong\u003e\u0026plusmn;\u0026nbsp;\u003c/strong\u003e3.92\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003csup\u003ea\u003c/sup\u003eFinal concentration of AMD spiked into urine samples in BR (pH 5.0) supporting electrolyte medium\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003csup\u003eb\u003c/sup\u003eValues are the average of three independent analysis\u003c/p\u003e\n\u003cp\u003e\u003csup\u003ec\u003c/sup\u003eRecovery%:(detected/added)x100\u0026nbsp;\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eAs a result of the literature review, it was determined that various studies were conducted using different analytical techniques for the analysis of AMD, a Class III antiarrhythmic drug. Studies using electrochemical techniques are relatively scare. Scientists have used disposable E-PGEs as electrode materials for years due to their economical, easily accessible, and renewable properties. In this present study, the electrochemical properties of AMD were investigated in different supporting electrolytes and a wide pH range by using these advantageous properties of E-PGE. In the supporting electrolyte medium of BR (pH 5.0), an irreversible wave was obtained at a potential of approximately +0.94 V with the cyclic voltammetry technique. In the evaluation of the data obtained from both cyclic and square-wave voltammetry techniques, an electrochemical mechanism for AMD on E-PGE was proposed. This electrochemical mechanism proves that 2 electrons and 2 protons contribute to the process. An electroanalytical technique was developed for the quantification of AMD in BR (pH 5.0) using the square-wave voltammetry. Good linearity was obtained between 0.125 \u0026mu;g/mL and 6.862 \u0026mu;g/mL of AMD under optimum operating conditions on disposable E-PGE. The LOD value of 0.027 \u0026mu;g/mL was calculated for single-use E-PGE, which is better than other analytical techniques. The accuracy of the method was tested by performing recovery studies on pharmaceutical and urine samples. In repeatability studies, the inter-day % RSD values for oxidation peak current and voltage were 3.84% and 0.42%, respectively. This shows that the precision of the method is good. Continuing the study, an interference study was performed with 6.862 \u0026mu;g/mL AMD in AA, UA, DP, NE, EP, P4, S, TES, and some inorganic substances (Fe\u003csup\u003e2+\u003c/sup\u003e, Cu\u003csup\u003e2+\u003c/sup\u003e, Zn\u003csup\u003e2+\u003c/sup\u003e, Co\u003csup\u003e2+\u003c/sup\u003e, Ni\u003csup\u003e2+\u003c/sup\u003e, NO\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e-\u003c/sup\u003e, Cl\u003csup\u003e-\u003c/sup\u003e, and SO\u003csub\u003e4\u003c/sub\u003e\u003csup\u003e2-\u003c/sup\u003e) solutions. In these interference experiments, the added substances did not cause an analytically significant change in anodic peak current and voltage for AMD. Thus, it was proven that AMD concentrations in biological fluids can be measured reliably voltammetrically. In general, it is considered that the developed square-wave voltammetric method may be an alternative to chromatographic and spectroscopic methods in the literature due to its advantages, such as being sensitive, fast, and economical, not requiring separation and purification, and being operable with small amounts of sample.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAuthors\u0026rsquo; contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eS\u0026uuml;lbiye DOĞAN:\u003c/strong\u003e Conceptualization, Methodology, Investigation.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAbdulkadir Levent\u003c/strong\u003e: Validation, Data curation, Writing- original draft, Writing- review \u0026amp; editing, Supervision.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFinancial interests or Conflicts of interest:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll authors certify that they have no affiliations with or involvement in any organization or entity with any financial interest or non-financial interest in the subject matter or materials discussed in this manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eData will be made available on request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eFatima N, Mandava K, Khatoon F, et al (2022) CLInical Profile and Side Effects of chronic use of oral Amiodarone in cardiology outpatients department (CLIPSE-A Study)- A prospective observational study. Annals of Medicine and Surgery 80:. https://doi.org/10.1016/j.amsu.2022.104167\u003c/li\u003e\n\u003cli\u003eSoar J, Perkins GD, Maconochie I, et al (2019) European Resuscitation Council Guidelines for Resuscitation: 2018 Update \u0026ndash; Antiarrhythmic drugs for cardiac arrest. Resuscitation 134:99\u0026ndash;103. https://doi.org/10.1016/j.resuscitation.2018.11.018\u003c/li\u003e\n\u003cli\u003eYamreudeewong W, DeBisschop M, Martin LG, Lower DL (2003) Potentially Significant Drug Interactions of Class III Antiarrhythmic Drugs. Drug Safety 26:421\u0026ndash;438. https://doi.org/10.2165/00002018-200326060-00004\u003c/li\u003e\n\u003cli\u003eKinoshita H, Taniguchi T, Nishiguchi M, et al (2003) An autopsy case of combined drug intoxication involving verapamil, metoprolol and digoxin. Forensic Science International 133:107\u0026ndash;112. https://doi.org/10.1016/S0379-0738(03)00056-2\u003c/li\u003e\n\u003cli\u003eHa HR, Kozlik P, Stieger B, et al (2001) Metabolism of amiodarone. Journal of Chromatography B: Biomedical Sciences and Applications 757:309\u0026ndash;315. https://doi.org/10.1016/S0378-4347(01)00165-7\u003c/li\u003e\n\u003cli\u003eMaes A, Baert K, Croubels S, et al (2006) Determination of amiodarone and desethylamiodarone in horse plasma and urine by high-performance liquid chromatography combined with UV detection and electrospray ionization mass spectrometry. Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences 836:47\u0026ndash;56. https://doi.org/10.1016/j.jchromb.2006.03.038\u003c/li\u003e\n\u003cli\u003eBolderman RW, Hermans JJR, Maessen JG (2009) Determination of the class III antiarrhythmic drugs dronedarone and amiodarone, and their principal metabolites in plasma and myocardium by high-performance liquid chromatography and UV-detection. Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences 877:1727\u0026ndash;1731. https://doi.org/10.1016/j.jchromb.2009.04.029\u003c/li\u003e\n\u003cli\u003eKhan MA, Kumar S, Jayachandran J, et al (2005) Validation of a stability indicating LC method for amiodarone HCL and related substances. Chromatographia 61:599\u0026ndash;607. https://doi.org/10.1365/s10337-005-0554-3\u003c/li\u003e\n\u003cli\u003eAl Dhawailie AA (1995) High performance liquid chromatographic determination of amiodarone in plasma and tissues. Analytical Letters 28:2391\u0026ndash;2400. https://doi.org/10.1080/00032719508000380\u003c/li\u003e\n\u003cli\u003eEl-Bagary RI, Elkady EF, Mowaka S, Attallah MA (2015) Validated HPLC and ultra-HPLC methods for determination of dronedarone and amiodarone-application for counterfeit drug analysis. Journal of AOAC International 98:1496\u0026ndash;1502. https://doi.org/10.5740/jaoacint.15-054\u003c/li\u003e\n\u003cli\u003eKuhn J, G\u0026ouml;tting C, Kleesiek K (2010) Simultaneous measurement of amiodarone and desethylamiodarone in human plasma and serum by stable isotope dilution liquid chromatography-tandem mass spectrometry assay. Journal of Pharmaceutical and Biomedical Analysis 51:210\u0026ndash;216. https://doi.org/10.1016/j.jpba.2009.08.004\u003c/li\u003e\n\u003cli\u003eRiekes MK, Tagliari MP, Granada A, et al (2010) Enhanced solubility and dissolution rate of amiodarone by complexation with \u0026beta;-cyclodextrin through different methods. Materials Science and Engineering C 30:1008\u0026ndash;1013. https://doi.org/10.1016/j.msec.2010.05.001\u003c/li\u003e\n\u003cli\u003eHasegawa M, Takenaka S, Kuwamura M, et al (2007) Urinary metabolic fingerprinting for amiodarone-induced phospholipidosis in rats using FT-ICR MS. Experimental and Toxicologic Pathology 59:115\u0026ndash;120. https://doi.org/10.1016/j.etp.2007.04.001\u003c/li\u003e\n\u003cli\u003eLiu N, Gao W, Song J-F (2006) Catalytic Adsorptive Stripping Voltammetry at a Carbon Paste Electrode for the Determination of Amiodarone. Chinese Journal of Chemistry 24:1657\u0026ndash;1661. https://doi.org/10.1002/cjoc.200690310\u003c/li\u003e\n\u003cli\u003eHasanzadeh M, Pournaghi-Azar MH, Shadjou N, Jouyban A (2014) Magnetic nanoparticles incorporated on functionalized mesoporous silica: An advanced electrochemical sensor for simultaneous determination of amiodarone and atenolol. RSC Advances 4:4710\u0026ndash;4717. https://doi.org/10.1039/c3ra45433a\u003c/li\u003e\n\u003cli\u003eBanan K, Niknam S, Ahmadi M, et al (2024) Molecularly imprinted electrochemical sensor based on carbon nanofibers for Amiodarone determination. Microchemical Journal 200:. https://doi.org/10.1016/j.microc.2024.110365\u003c/li\u003e\n\u003cli\u003eLevent A, \u0026Ouml;nal G (2018) Application of a pencil graphite electrode for voltammetric simultaneous determination of ascorbic acid, norepinephrine, and uric acid in real samples. Turkish Journal of Chemistry 42:460\u0026ndash;471. https://doi.org/10.3906/kim-1708-14\u003c/li\u003e\n\u003cli\u003eKili\u0026ccedil; A, Aslan M, \u0026Ouml;nal G, Levent A (2023) Firstly electrochemical investigetions and determination of anticoagulant drug edoxaban at single-use pencil graphite electrode: an eco-friendly and cost effective voltammetric method. DARU, Journal of Pharmaceutical Sciences 31:233\u0026ndash;241. https://doi.org/10.1007/s40199-023-00478-8\u003c/li\u003e\n\u003cli\u003eAtay B, \u0026Ouml;nal G, Levent A (2023) Electrochemical investigations and determination of antineoplastic agent etoposide at single-use pencil graphite electrode: an eco-friendly and cost effective voltammetric method. Monatshefte fur Chemie 154:765\u0026ndash;773. https://doi.org/10.1007/s00706-023-03079-y\u003c/li\u003e\n\u003cli\u003e\u0026Ouml;zer M, Levent A (2024) Application of eco‐friendly disposable pencil graphite sensor for electrochemical evaluation and determination of podophyllotoxin using in cancer treatment. ChemistrySelect 9:. https://doi.org/10.1002/slct.202305100\u003c/li\u003e\n\u003cli\u003eAnnu, Sharma S, Jain R, Raja AN (2020) Review\u0026mdash;Pencil Graphite Electrode: An Emerging Sensing Material. Journal of The Electrochemical Society 167:037501. https://doi.org/10.1149/2.0012003jes\u003c/li\u003e\n\u003cli\u003eHussien EM, Rizk MS, Daoud AM, El-Eryan RT (2022) An Eco-friendly Pencil Graphite Sensor for Voltammetric Analysis of the Antidepressant Vilazodone Hydrochloride. Electroanalysis 34:1402\u0026ndash;1410. https://doi.org/10.1002/elan.202100457\u003c/li\u003e\n\u003cli\u003eSawkar RR, Patil VB, Shanbhag MM, et al (2021) Detection of ketorolac drug using pencil graphite electrode. Biomedical Engineering Advances 2:100009. https://doi.org/10.1016/j.bea.2021.100009\u003c/li\u003e\n\u003cli\u003eErsali H, Levent A (2024) Green Voltammetric Detection of Ophthalmic Drug Nepafenac Using Pencil Graphite Electrode as a Responsive Disposable Electrochemical Sensor. ChemistrySelect 9:. https://doi.org/10.1002/slct.202403549\u003c/li\u003e\n\u003cli\u003eWang J (2006) Analytical Electrochemistry. In: Analytical Electrochemistry. Wiley\u003c/li\u003e\n\u003cli\u003eGadelHak Y, Hafez SHM, Mohamed HFM, et al (2023) Nanomaterials-modified disposable electrodes and portable electrochemical systems for heavy metals detection in wastewater streams: A review. Microchemical Journal 193:109043. https://doi.org/10.1016/j.microc.2023.109043\u003c/li\u003e\n\u003cli\u003eWang J, Kawde A-N, Sahlin E (2000) Renewable pencil electrodes for highly sensitive stripping potentiometric measurements of DNA and RNA. The Analyst 125:5\u0026ndash;7. https://doi.org/10.1039/a907364g\u003c/li\u003e\n\u003cli\u003eLevent A (2017) Voltammetric behavior of acebutolol on pencil graphite electrode: highly sensitive determination in real samples by square-wave anodic stripping voltammetry. Journal of the Iranian Chemical Society 14:2495\u0026ndash;2502. https://doi.org/10.1007/s13738-017-1184-z\u003c/li\u003e\n\u003cli\u003eBard AJ., Faulkner LR. (2001) Electrochemical methods : fundamentals and applications. John Wiley \u0026amp; Sons, Inc.\u003c/li\u003e\n\u003cli\u003eLaviron E, Roullier L, Degrand C (1980) A multilayer model for the study of space distributed redox modified electrodes: Part II. Theory and application of linear potential sweep voltammetry for a simple reaction. Journal of Electroanalytical Chemistry and Interfacial Electrochemistry 112:11\u0026ndash;23. https://doi.org/10.1016/S0022-0728(80)80003-9\u003c/li\u003e\n\u003cli\u003eLaviron E, Roullier L, Degrand C (1980) A multilayer model for the study of space distributed redox modified electrodes. Journal of Electroanalytical Chemistry and Interfacial Electrochemistry 112:11\u0026ndash;23. https://doi.org/10.1016/S0022-0728(80)80003-9\u003c/li\u003e\n\u003cli\u003eHermosa BG, Kauffmann J-M, Patriarche GJ, Guilbault GG (1986) Electrochemical Behaviour of Benzofuran Derivatives of Pharmaceutical Interest at Solid Electrodes. Analytical Letters 19:2011\u0026ndash;2021. https://doi.org/10.1080/00032718608064543\u003c/li\u003e\n\u003cli\u003eBritton HTS, Robinson RA (1931) CXCVIII.\u0026mdash;Universal buffer solutions and the dissociation constant of veronal. J Chem Soc 1456\u0026ndash;1462. https://doi.org/10.1039/JR9310001456\u003c/li\u003e\n\u003cli\u003eYurdem A, Aslan M, Aral H, Levent A (2024) First electrochemical investigation and determination of non-steroidal anti-inflammatory drug etofenamate using disposable pencil graphite electrode with voltammetric techniques. Analytica Chimica Acta 1299:342377. https://doi.org/10.1016/j.aca.2024.342377\u003c/li\u003e\n\u003cli\u003eAslan M, Levent A (2024) Electrochemical investigation of the antimicrobial agent daptomycin utilizing disposable pencil graphite electrode and DNA interaction with green techniques. Microchemical Journal 207:112191. https://doi.org/10.1016/j.microc.2024.112191\u003c/li\u003e\n\u003cli\u003eErmer J, McB. Miller JH (2005) Method Validation in Pharmaceutical Analysis. Wiley\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"ionics","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":" Learn more about [Ionics](https://www.springer.com/journal/11581) ","snPcode":"11581","submissionUrl":"https://mc.manuscriptcentral.com/ionics","title":"Ionics","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Amiodarone, Antiarrhythmic drug, Disposable pencil graphite electrode, Voltammetry","lastPublishedDoi":"10.21203/rs.3.rs-5677107/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5677107/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe electrochemical properties of the antiarrhythmic drug amiodarone were investigated using square-wave and cyclic voltammetry techniques in Britton\u0026ndash;Robinson buffer solution (pH 5.0) with a disposable electrochemical activated pencil graphite electrode. In cyclic voltammetry measurements, it was observed that amiodarone exhibited a well-defined irreversible oxidation peak at a voltage of approximately\u0026thinsp;+\u0026thinsp;0.94 V. With optimized instrument parameters, amiodarone exhibited a linear response in the concentration range of 0.125 \u0026micro;g/mL to 6.862 \u0026micro;g/mL in Britton\u0026ndash;Robinson buffer solution (pH 5.0) on a disposable electrochemical-activated pencil graphite electrode. The resulting calibration curve was Ip(\u0026micro;A)\u0026thinsp;=\u0026thinsp;0.113 C(\u0026micro;g/mL)\u0026thinsp;+\u0026thinsp;0.039 (\u003cem\u003er\u0026thinsp;=\u003c/em\u003e\u0026thinsp;0.998, n\u0026thinsp;=\u0026thinsp;9). The limit of detection and limit of quantification values for the voltammetric method were determined to be 0.027 \u0026micro;g/mL and 0.089 \u0026micro;g/mL, respectively. The simplicity, rapidity, and sensitivity of the developed voltammetric method are considered to be important advantages. In addition, the applicability of the proposed voltammetric method to drug and urine samples demonstrated the selectivity of the method. The results of the voltammetric technique developed for the analysis of amiodarone in pharmaceutical samples were supported by spectrophotometric results.\u003c/p\u003e","manuscriptTitle":"Investigation of electrochemical properties and detection of the antiarrhythmic drug amiodarone in pharmaceutical and urine samples using a disposable pencil graphite electrode","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-04-21 04:55:34","doi":"10.21203/rs.3.rs-5677107/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-04-01T13:34:15+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-04-01T11:19:07+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"96732669394499054145684029379486211311","date":"2025-03-28T12:20:25+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-03-25T15:04:37+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-03-25T09:07:04+00:00","index":"","fulltext":""},{"type":"submitted","content":"Ionics","date":"2025-03-24T22:00:14+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"ionics","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":" Learn more about [Ionics](https://www.springer.com/journal/11581) ","snPcode":"11581","submissionUrl":"https://mc.manuscriptcentral.com/ionics","title":"Ionics","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"5c278bf1-fd4a-4fef-b5fd-174ed0f42026","owner":[],"postedDate":"April 21st, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2025-04-21T04:55:34+00:00","versionOfRecord":[],"versionCreatedAt":"2025-04-21 04:55:34","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-5677107","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5677107","identity":"rs-5677107","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}