{"paper_id":"4c1cb4e7-8f36-406c-845b-5ed6d7dfbfe3","body_text":"A fluorescent probe for Hg 2+ specific recognition based on xanthene and its application in food detection and cell imaging | 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 A fluorescent probe for Hg 2+ specific recognition based on xanthene and its application in food detection and cell imaging Chenglu Zhang, Shiru Nie, Chang Liu, Yang zhang, Jinghao Guo This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4019763/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 7 You are reading this latest preprint version Abstract The mercury-loving unit aminothiourea was introduced into the xanthene fluorophore to synthesized the probe molecule NXH . NXH has a specific response to Hg 2+ , and with the addition of (0 ~ 50 µM) Hg 2+ , the fluorescence intensity of the probe solution was quenched from 2352 a.u. to about 308 a.u.. The probe NXH exhibited excellent detection performance of high sensitivity (LOD = 96.3 nM), real-time response (105 s), wide pH range (2.1 ~ 9.3), and strong anti-interference ability for Hg 2+ . At the same time, the probe NXH has wide range of applications for Hg 2+ detection, which can be used to create molecular logic gates, make Hg 2+ detection test paper, as well as the fluorescence imaging of Hg 2+ in Hela live cells and tea samples. xanthene Hg2+ food samples cell imaging Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15 Figure 16 Figure 17 1. Introduction Mercury (Hg) is the only element in the periodic table that has its own environmental convention, because of its serious harm to the environment and health, namely the Minamata Convention on Mercury [ 1 ] . It is also one of the \"10 Chemicals of Major Public Health Concern\" promulgated by the United Nations [ 2 ] .Mercury exists in many forms in the environment (elemental mercury, inorganic mercury and organic mercury), and no matter which form mercury exists, it will have toxic effects on mammals [ 3 , 4 ] . Mercury vapor is highly lipophilic and diffusible, it can easily cross the blood-brain barrier and cell membranes,and be oxidized into positive divalent mercury ions (Hg 2+ ) in the cells, which will accumulate in the kidneys and brains over time. Inorganic mercury is rapidly converted into organic mercury (methylmercury) in ecosystems, and is enriched in the food chain as methylmercury, eventually entering the human body [ 5 – 7 ] . The biological toxicity of mercury to humans is mainly manifested in inducing neuron death, damaging antioxidant and immune regulation functions, and destroying the normal functions of kidney and cardiovascular system [ 8 – 12 ] . The detection of Hg 2+ has evolved from traditional instrumental analysis (such as spectrophotometry, high-performance liquid chromatography, and inductively coupled plasma emission spectrometry [ 13 – 16 ] ) to sensing detection in recent years. The sensing analysis method includes the advantages of the sensitivity and accuracy of the traditional detection method, and makes up for the shortcomings of the traditional detection in terms of cost investment, operation technology and practical application. Fluorescent probe sensing technology has been widely used in the detection of Hg 2+ in the environment and organisms due to its advantages of simple fabrication method, easy operation and and biologically non-destructive in situ imaging [ 17 – 21 ] . As shown in Table S1 , according to the recognition mechanism of Hg 2+ , it can be mainly divided into two types of fluorescent probes: complexation probes [ 22 – 24 ] and reaction probes [ 25 – 27 ] . Complexation probes often be designed by introducing a recognition site with specific response to Hg 2+ into the probe molecule. Reaction probes often be designed based on Hg 2+ induced ring-opening reaction, desulfurization reaction and thioacetal deprotection. The xanthene molecule is formed by an oxygen bridge connecting two benzene rings, this molecular structure makes the xanthene have a good rigid plane. Meanwhile, the xanthene molecule also has good water solubility and low biological toxicity, which makes it an advantageous fluorophore for the construction of fluorescent detection probes in vivo [ 28 – 30 ] . Based on the above-mentioned investigation of the structure design of the specific recognition of Hg 2+ fluorescent probe (as shown in Table S1 ), in this paper, xanthene was used as the fluorophore and the mercury-philic sulfur-containing group aminothiourea was used as the response group to construct the mercury coordination fluorescent probe NXH . Due to the low toxicity and good biocompatibility of anthracene fluorophore, fluorescent probe NXH is expected to realize the qualitative and quantitative detection of Hg 2+ in environment and organism. 2. Experiment 2.1 Materials and methods The reagents we used were all analytical purity purchased from suppliers, and no further purification was needed. Please refer to the supporting information for the preparation of specific reserve liquid and instrument information. 2.2 Synthesis The detailed method of synthesis of intermediate Xn2 can be found in the supporting information. Synthesis of target probe NXH : Xn2 (0.31 g, 1.3 mmol) and aminothiourea (0.12 g, 1.3 mmol) were dissolved in 10 mL of absolute ethanol, and the reaction system was heated and refluxed in N 2 atmosphere for 7 h, and TLC was used to monitor the reaction process. After the reaction is completed, it was cooled to room temperature, three times the amount of ice water was poured in, and the orange-brown solid precipitated, filtered, washed, and dried to obtain crude NXH . The obtained crude product was purified by silica gel column chromatography (eluent: V petroleum ether : V ethyl acetate = 3:1) to obtain pure NXH . ( Z )-2-((6-methoxy-2,3-dihydro-1 H -xanthen-4-yl)methylene)hydrazine-1-carbothioamide ( NXH ): orange brown solid in yield 72.4%, m.p.m.p. 182.7 ~ 183.4 ℃, IR (KBr) ν / cm − 1 :3305, 3280, 3030, 2680, 1740, 1605, 1275. 1 H NMR (400 MHz, DMSO- d 6 ) δ 11.17 (s, 2H), 8.17 (s, 1H), 7.99 (s, 1H),7.01 (s, 1H), 6.62 (s, 1H), 6.61 (s, 1H), 5.32 (s, 1H), 3.74 (d, J = 3.0 Hz, 3H), 2.68 (d, J = 1.7 Hz, 2H), 2.66 (s, 2H), 1.46–1.45 (m, 2H). 13 C NMR (101 MHz, DMSO- d6 ) δ 22.70, 29.10, 30.92, 55.39, 100.00, 108.48, 108.86, 109.38, 121.52, 129.66, 140.20, 144.16, 153.02, 153.13, 160.22, 180.87. HRMS (positive-ESIMS) calcd for C 16 H 17 N 3 O 2 S [M + H] + 316.1058, found 316.1014. 3. Results and discussion 3.1 Ultraviolet titration experiments Hg 2+ with different concentrations (0,10,20,30,40,50 µM) were added into the NXH solution (10 µM) for ultraviolet titration experiment. The ultraviolet absorption spectra corresponding to different concentrations of mercury ions were recorded respectively. As shown in Fig. 2 , the probe NXH solution has two maximum ultraviolet absorption peaks, which were located at 300 nm and 425 nm respectively. With the addition of Hg 2+ (0 ~ 50 µM), the ultraviolet absorption peak gradually increases, which means that the probe NXH is responsive to Hg 2+ . 3.2 Fluorescence titration experiments Different concentrations of Hg 2+ (0, 5, 10, 15, 20, 30, 40, 50 µM) were adde into probe NXH solution (10 µM), and the fluorescence spectrum at corresponding Hg 2+ concentration was recorded. As shown in Fig. 3 a, the probe NXH solution itself has a strong fluorescence emission at 545 nm with an intensity of 2352 a.u. With the addition of (0 ~ 50 µM) Hg 2+ , the fluorescence intensity of NXH -Hg 2+ solution system was gradually quenched to about 308 a.u, showing a significant \"turn-off\" phenomenon. In order to calculate the sensitivity of probe NXH to Hg 2+ detection, the linear curve was drawn with the fluorescence intensity of probe NXH at 545 nm as the ordinate and the concentration of Hg 2+ as the abscissa. As shown in Fig. 3 b, there has a good linear relationship between them, and the linear regression equation is Y = -40.17401 X + 2304.52099 and the linear determination coefficient is R 2 = 0.99047. According to the detection limit calculation formula: LOD = 3σ/k (where σ is the standard deviation of the blank measurement, and k is the slope) [ 31 ] , the detection limits of the probe NXH for Hg 2+ was determined to be 96.3 nM. To sum up, the fluorescent probe NXH has high sensitivity for the detection of Hg 2+ . The fluorescence color of probe NXH was predicted by CIE chromaticity diagram. As shown in Fig. 4 , the CIE coordinates of the probe NXH correspond to the yellow area of the chromaticity disk, and it was speculated that the probe NXH solution may emit photochromic fluorescence. To verify the above speculation, the fluorescence color of the probe solution in the presence of different concentrations of Hg 2+ (0 ~ 50 µM) was observed under ultraviolet lamp (365 nm). As shown in Fig. 5 , NXH solution emits strong yellowish fluorescence, and with the increase of Hg 2+ concentration, the fluorescence intensity of the solution gradually weakened to almost no light. The fluorescence of probe solution changes obviously in the presence of different concentrations of Hg 2+ , which preliminarily shows that probe NXH has certain practical application potential. 3.3 Complexometric titration experiments The complexation constant Ka of probe NXH to Hg 2+ was calculated by using the benzene-hildebrand equation (B-H equation). As shown in Fig. 6 , 1 /[Hg 2+ ] was selected as the abscissa (Hg 2+ concentrations are 5, 10, 15, 20, 30, 40 and 50 µM, respectively), and 1/(F-F min ) was selected as the ordinate (F min and F represent fluorescence intensity values corresponding to Hg 2+ concentrations of 0 and 5 ~ 50 µM, respectively). There has a good linear relationship between them, and the linear determination coefficient is R 2 = 0.99882. According to the B-H equation, the complexation constant is 1.1×10 4 M − 1 , which shows that the probe NXH has strong complexation ability to Hg 2+ . 3.4 Selective experiments To explore the specificity of NXH for Hg 2+ recognition, thirty representative analytes, such as Na + , Al 3+ , K + , Ag + ,Ca 2+ , Mg 2+ , Zn 2+ , Fe 2+ , Fe 3+ , Sn 2+ , Pb 2+ , Cu 2+ , Ba 2+ , Ga 3+ , Ni 2+ , Hg 2+ , F − , Cl − , Br − , I − , SO 4 2− , HSO 3 − , SO 3 2− , NO 3 − , NO 2 − , PO 4 3− , HPO 4 2− , H 2 PO 4 − , CO 3 2− and HCO 3 − were selected for selectivity experiments. As shown in Fig. 7 , the probe NXH solution (10 µM) had a strong fluorescence emission at 545 nm, and when the above 29 analyte solutions (50 µM) were added to the probe NXH solution (10 µM), the fluorescence intensity has no obvious change. Only when Hg 2+ (50 µM) was added, the fluorescence intensity of the solution decreases greatly. It shows that the response of probe NXH to Hg 2+ is specific. 3.5 Interference experiments To test whether the detection of Hg 2+ by probe NXH will be interfered by other ions, the anti-interference experiments was conducted, and the results were shown in Fig. 8 . When only interfering substances were added, the fluorescence of the solution system did not change obviously. On this basis, the fluorescence intensity of the solution was greatly quenched by adding Hg 2+ (50 µM), which was close to the fluorescence intensity when only Hg 2+ was added to the probe NXH solution. It shows that the recognition of Hg 2+ by NXH will not be interfered by other ions, and it can be used for the detection of Hg 2+ in real environment. 3.6 Time response experiments We carried out time response experiments to evaluate the real-time detection ability of probe NXH for Hg 2+ . As shown in Fig. 9 , when adding 30 µM and 50 µM Hg 2+ to probe NXH solution (10 µM) respectively, similar phenomena was observed, The fluorescence intensity of the solution decreased to the lowest within 105 s, and then remained stable. It shows that the probe NXH can quickly identify Hg 2+ within 105 s. 3.7 pH effect experiments In order to test the pH application range of probe NXH , the pH dependence experiments were carried out. As shown in Fig. 10 , the fluorescence intensity of probe NXH was not affected in the range of pH = 1.1 ~ 12.1. When pH > 9.3, the fluorescence intensity of the NXH -Hg 2+ solution system increased slightly. The optimum pH range for probe NXH to recognize Hg 2+ is pH = 2.1 ~ 9.3, including physiological pH range. Therefore, it can be considered to recognize Hg 2+ in organisms. 3.8 Reversibility experiments The repeatability of probe NXH for Hg 2+ detection was evaluated by using EDTA as Hg 2+ scavenger. As shown in Fig. 11 , the same amount of Hg 2+ and EDTA were alternately added to the probe NXH solution (10 µM), it can be observed that the fluorescence signal of the solution appears 4 times alternating \"on-off-on\" phenomenon. And the fluorescence changes of the solution system corresponding to the above phenomena can be observed under the ultraviolet lamp (365 nm) (as shown in Fig. 12 ), indicating that the NXH has good reusability for the detection of Hg 2+ . 3.9 Mechanism exploration experiments Firstly, the Job's curve was drawn to determine the coordination ratio of NXH and Hg 2+ . As shown in Fig. S4, when the ratio of [Hg 2+ ]/[Hg 2+ + NXH ] is 0.33, that is, the ratio of NXH to Hg 2+ is 2: 1, the fluorescence intensity of the solution system is the minimum. HRMS titration experiments was used to further determine the complexation ratio of NXH and Hg 2+ . As shown in Fig. S5, Before adding Hg 2+ , a signal peak consistent with the expected molecular weight of probe NXH was generated at 316.1014. After adding Hg 2+ , the new signal peak at 831.0861 was similar to the molecular weight of the complex formed by NXH and Hg 2+ in a 2:1 ratio. Next, the 1 H NMR titration experiments was used to determine the binding site of probe NXH and Hg 2+ . As shown in Fig. 13 , it was found that after the addition of Hg 2+ , only the characteristic H belonging to imine disappeared in the probe NXH molecule. Based on Gaussian 09 program, the B3LYP/ 6-311 + + G (d, p) method, density functional theory calculation was used to explain the fluorescence change of Hg 2+ recognized by NXH . As shown in Fig. S6. The highest occupancy orbital (HOMO) of the complex NXH -Hg 2+ was mainly distributed in the xanthene fluorophore, partly in the ligand, while the lowest empty orbital (LUMO) was completely distributed on the ligand, away from the fluorophore, and there was a flow of electrons migrating from the fluorophore to the ligand, which was contrary to the fluorescence production mechanism. In addition, according to the energy gap value calculation formula: Egap = LUMO - HOMO The calculated energy gap values of NXH and NXH -Hg 2+ were 0.11237 a.u. and 0.22482 a.u., respectively. Obviously, the energy gap value of NXH -Hg 2+ is larger, and generally, the larger energy gap value is not conducive to the generation of fluorescence signals. To sum up, the mechanism of Hg 2+ recognition by probe NXH was shown in Fig. 14 . 3.10 Practical applications 3.10.1 Tea samples Food is one of the main ways for human body to ingest mercury ions. Therefore, three tea samples, Jinjunmei, Biluochun and Qimen Hongcha were selected to evaluate the ability of the probe NXH to detect Hg 2+ in food samples. The tea samples were pre-treated by placing 0.5 g of crushed tea in 20 mL of concentrated nitric acid and soaking overnight. and After dissolution and centrifugation, the pH of the sample was adjusted to be neutral with sodium hydroxide solution. The fluorescence changes of the NXH -tea sample after adding Hg 2+ were observed under UV light (365 nm). As shown in Fig. 15 , the sample solutions pretreated with probe NXH emitted bright yellow fluorescence, and the solutions were quenched to almost no fluorescence after the addition of Hg 2+ , which suggests that the probe NXH has the ability to qualitatively detect Hg 2+ in food samples. The standard addition recovery method was used to measure the ability of probe NXH to quantitatively detect Hg 2+ in tea samples. Add 15, 30 and µM Hg 2+ to the tea samples respectively, and calculate the detected concentration of Hg 2+ in the solution by combining the linear regression equation Y = -40.17401 X + 2304.520991 obtained from the fluorescence titration experiment in 3.2. As shown in Table S2, the recovery rate of Hg 2+ in the three tea samples was maintained at 99.47 ~ 102.87%, and the RSD values of each group of data were less than 1.83%. It indicating that the probe NXH can quantitative detection of Hg 2+ in the tea samples. 3.10.2 Fluorescence test paper In view of the application potential of the fluorescent probe NXH for the detection of Hg 2+ in food samples and the excellent performance of Hg 2+ detection, the probe NXH was tried to be made into test paper. Dropping different concentrations of Hg 2+ solution onto the surface of the test paper, the phenomenon shown in Fig. 16 can be observed under the ultraviolet lamp (365 nm). With the increase of Hg 2+ concentration, the fluorescence on the surface of the test paper gradually weakened to almost disappear, indicating that the fluorescence detection test paper made of probe NXH can qualitatively identify Hg 2+ . 3.10.3 Cell imaging It is of great significance to detect the level of Hg 2+ in organisms, so we try to apply the probe NXH to the biological imaging detection of Hg 2+ . As shown in Fig. S7, the cell viability of Hela cells remained above 83% after 24 hours of treatment with different concentrations of probe NXH solution, indicating that the probe NXH has low cytotoxicity. As shown in Fig. 17 , when cells were incubated with probe NXH (10 µM) for 30 min, strong green fluorescence was observed (Fig. 17 d). After incubation with 30 µM Hg 2+ for 30 min, the green fluorescence observed in the cells weakened, and the concentration of Hg 2+ increased to 50 µM, almost no fluorescence could be seen in the cells (Fig. 17 f). 4. Conclusion The mercury-philic aminothiourea group was introduced into the xanthene fluorophore, and a fluorescent probe NXH with specific response to Hg 2+ was developed. NXH recognizes Hg 2+ by fluorescence quenching. When (0 ~ 50 µM) Hg 2+ was added to the probe solution, the fluorescence intensity of the solution was negatively correlated with the concentration of Hg 2+ added. The probe NXH has a wide pH range (2.1 ~ 9.3), fast response speed (105 s) and high sensitivity (LOD = 96.3 nM), which has a good application prospect. The probe NXH has been successfully used to make Hg 2+ test strips and can fluorescently identify Hg 2+ in tea samples and biological cells. Declarations Competing Interests There are no conflicts of interest. Ethical Approval This article does not contain any studies involving human participants performed by any of the authors. Funding No funding, grants, or other support was received during the preparation of this manuscript. Author Contribution C L-Z:Investigation, Writing - review & editing, Methodology;S R-N:Investigation, Conceptualization, Writing - original draft, Formal analysis;C-L:Investigation, Formal analysis;Y-Z:Investigation, Formal analysis;J H-G::Investigation, Formal analysis;All authors reviewed the manuscript. Data Availability The data generated and analyzed will be made available upon reasonable request from the corresponding authors. References Coulter M (2014) The Minamata Convention On Mercury: Past, Present, And Future Environmental Health[J]. Sustainable Dev Law Policy 14:12–13 Jain J, Gauba P (2017) Heavy metal toxicity-implications on metabolism and health[J]. Int J pharma Bio Sci 8(4):452–460 Clifton JC (2007) Mercury Exposure and Public Health[J]. 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Opt Mater 123:111929–111935 Statements & Declarations Scheme 1 Scheme 1 is available in the Supplementary Files section Additional Declarations No competing interests reported. Supplementary Files Scheme1.png Scheme 1 Synthetic method of the target probe NXH Supportinginformation.docx Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 24 Mar, 2024 Reviews received at journal 23 Mar, 2024 Reviewers agreed at journal 14 Mar, 2024 Reviewers invited by journal 12 Mar, 2024 Submission checks completed at journal 06 Mar, 2024 Editor assigned by journal 06 Mar, 2024 First submitted to journal 06 Mar, 2024 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. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {\"props\":{\"pageProps\":{\"initialData\":{\"identity\":\"rs-4019763\",\"acceptedTermsAndConditions\":true,\"allowDirectSubmit\":false,\"archivedVersions\":[],\"articleType\":\"Research Article\",\"associatedPublications\":[],\"authors\":[{\"id\":276890668,\"identity\":\"3e2b9dcc-e388-491d-acaf-88dc291a7084\",\"order_by\":0,\"name\":\"Chenglu 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University\",\"correspondingAuthor\":false,\"prefix\":\"\",\"firstName\":\"Jinghao\",\"middleName\":\"\",\"lastName\":\"Guo\",\"suffix\":\"\"}],\"badges\":[],\"createdAt\":\"2024-03-06 07:21:08\",\"currentVersionCode\":1,\"declarations\":\"\",\"doi\":\"10.21203/rs.3.rs-4019763/v1\",\"doiUrl\":\"https://doi.org/10.21203/rs.3.rs-4019763/v1\",\"draftVersion\":[],\"editorialEvents\":[],\"editorialNote\":\"\",\"failedWorkflow\":false,\"files\":[{\"id\":52450800,\"identity\":\"f2b3ce99-8c1c-4296-9ffb-5732e6ac56dc\",\"added_by\":\"auto\",\"created_at\":\"2024-03-11 19:09:52\",\"extension\":\"png\",\"order_by\":1,\"title\":\"Figure 1\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":13159,\"visible\":true,\"origin\":\"\",\"legend\":\"\\u003cp\\u003eStructure of fluorescent probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e\\u003c/p\\u003e\",\"description\":\"\",\"filename\":\"image1.png\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-4019763/v1/a06e9743ab425d5c0a508202.png\"},{\"id\":52449927,\"identity\":\"ad1bc2a2-2e82-47cf-8555-e8a9ded696f0\",\"added_by\":\"auto\",\"created_at\":\"2024-03-11 19:01:52\",\"extension\":\"png\",\"order_by\":2,\"title\":\"Figure 2\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":20655,\"visible\":true,\"origin\":\"\",\"legend\":\"\\u003cp\\u003eUltraviolet titration spectra of \\u003cstrong\\u003eNXH \\u003c/strong\\u003e(10 µM) identifying Hg\\u003csup\\u003e2+\\u003c/sup\\u003e (0~50 µM)\\u003c/p\\u003e\",\"description\":\"\",\"filename\":\"image2.png\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-4019763/v1/09210ec61b8ef943f96e7db4.png\"},{\"id\":52450802,\"identity\":\"aa343698-fe52-42ad-81f0-ab0555c700a2\",\"added_by\":\"auto\",\"created_at\":\"2024-03-11 19:09:52\",\"extension\":\"png\",\"order_by\":3,\"title\":\"Figure 3\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":37932,\"visible\":true,\"origin\":\"\",\"legend\":\"\\u003cp\\u003e(a)Fluorescence spectra under different Hg\\u003csup\\u003e2+\\u003c/sup\\u003e concentrations(0~ 50 µM)\\u003cstrong\\u003e \\u003c/strong\\u003e(b)Linear relationship between probe fluorescence intensity and Hg\\u003csup\\u003e2+\\u003c/sup\\u003e (0 ~ 50 µM) concentration (\\u003cem\\u003eλ\\u003c/em\\u003e\\u003csub\\u003eex\\u003c/sub\\u003e = 425 nm)\\u003c/p\\u003e\",\"description\":\"\",\"filename\":\"image3.png\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-4019763/v1/57c3217431aa688826e44989.png\"},{\"id\":52449933,\"identity\":\"7826bbdb-143d-4c2c-81e6-36dde190189b\",\"added_by\":\"auto\",\"created_at\":\"2024-03-11 19:01:52\",\"extension\":\"png\",\"order_by\":4,\"title\":\"Figure 4\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":23925,\"visible\":true,\"origin\":\"\",\"legend\":\"\\u003cp\\u003eCIE chromaticity diagram of probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e\\u003c/p\\u003e\",\"description\":\"\",\"filename\":\"image4.png\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-4019763/v1/fe4408c61c59fb6cc4280676.png\"},{\"id\":52449940,\"identity\":\"13e253b3-7a37-4648-ac9b-15be546682e9\",\"added_by\":\"auto\",\"created_at\":\"2024-03-11 19:01:53\",\"extension\":\"png\",\"order_by\":5,\"title\":\"Figure 5\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":193539,\"visible\":true,\"origin\":\"\",\"legend\":\"\\u003cp\\u003eFluorescence changes of different concentrations of Hg\\u003csup\\u003e2+\\u003c/sup\\u003e (0 ~ 50 µM) in \\u003cstrong\\u003eNXH \\u003c/strong\\u003esolution (10 µM) under ultraviolet lamp\\u003c/p\\u003e\",\"description\":\"\",\"filename\":\"image5.png\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-4019763/v1/85f430e26cb54a259ecb41a1.png\"},{\"id\":52449931,\"identity\":\"f27db33f-d24e-47bd-a511-7129502beaf6\",\"added_by\":\"auto\",\"created_at\":\"2024-03-11 19:01:52\",\"extension\":\"png\",\"order_by\":6,\"title\":\"Figure 6\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":11557,\"visible\":true,\"origin\":\"\",\"legend\":\"\\u003cp\\u003eLinear relationship between 1/[Hg\\u003csup\\u003e2+\\u003c/sup\\u003e]\\u003cstrong\\u003e \\u003c/strong\\u003eand 1/(F-F\\u003csub\\u003emin\\u003c/sub\\u003e)\\u003c/p\\u003e\",\"description\":\"\",\"filename\":\"image6.png\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-4019763/v1/2053c35ad36434208a89174e.png\"},{\"id\":52449928,\"identity\":\"146a8223-b33d-4c6e-9d23-fa9da46c3bb8\",\"added_by\":\"auto\",\"created_at\":\"2024-03-11 19:01:52\",\"extension\":\"png\",\"order_by\":7,\"title\":\"Figure 7\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":28774,\"visible\":true,\"origin\":\"\",\"legend\":\"\\u003cp\\u003eSelective experiments of probe \\u003cstrong\\u003eNXH \\u003c/strong\\u003e(10 µM) for Hg\\u003csup\\u003e2+\\u003c/sup\\u003e (50 µM) (\\u003cem\\u003eλ\\u003c/em\\u003e\\u003csub\\u003eex\\u003c/sub\\u003e= 425 nm)\\u003c/p\\u003e\",\"description\":\"\",\"filename\":\"image7.png\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-4019763/v1/8a0994920906c8b089cf86cb.png\"},{\"id\":52449942,\"identity\":\"ffc5d01b-f2e9-4f59-ab55-21a3925037d5\",\"added_by\":\"auto\",\"created_at\":\"2024-03-11 19:01:53\",\"extension\":\"png\",\"order_by\":8,\"title\":\"Figure 8\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":55679,\"visible\":true,\"origin\":\"\",\"legend\":\"\\u003cp\\u003eInterference experiment of probe \\u003cstrong\\u003eNXH \\u003c/strong\\u003e(10 µM) for Hg\\u003csup\\u003e2+\\u003c/sup\\u003e (50 µM) (1.Blank, 2.Al\\u003csup\\u003e3+\\u003c/sup\\u003e, 3.K\\u003csup\\u003e+\\u003c/sup\\u003e, 4.Na\\u003csup\\u003e+\\u003c/sup\\u003e, 5.Ag\\u003csup\\u003e+\\u003c/sup\\u003e,6.Ca\\u003csup\\u003e2+\\u003c/sup\\u003e, 7.Mg\\u003csup\\u003e2+\\u003c/sup\\u003e, 8.Zn\\u003csup\\u003e2+\\u003c/sup\\u003e, 9.Fe\\u003csup\\u003e2+\\u003c/sup\\u003e, 10.Fe\\u003csup\\u003e3+\\u003c/sup\\u003e, 11.Sn\\u003csup\\u003e2+\\u003c/sup\\u003e, 12.Pb\\u003csup\\u003e2+\\u003c/sup\\u003e, 13.Cu\\u003csup\\u003e2+\\u003c/sup\\u003e, 14.Ba\\u003csup\\u003e2+\\u003c/sup\\u003e, 15.Ga\\u003csup\\u003e3+\\u003c/sup\\u003e, 16.Ni\\u003csup\\u003e2+\\u003c/sup\\u003e, 17.F\\u003csup\\u003e-\\u003c/sup\\u003e, 18.Cl\\u003csup\\u003e-\\u003c/sup\\u003e, 19.Br\\u003csup\\u003e-\\u003c/sup\\u003e, 20.I\\u003csup\\u003e-\\u003c/sup\\u003e­­­­­­, 21.SO\\u003csub\\u003e4\\u003c/sub\\u003e\\u003csup\\u003e2-\\u003c/sup\\u003e, 22.HSO\\u003csub\\u003e3\\u003c/sub\\u003e\\u003csup\\u003e-\\u003c/sup\\u003e, 23.SO\\u003csub\\u003e3\\u003c/sub\\u003e\\u003csup\\u003e2-\\u003c/sup\\u003e, 24.NO\\u003csub\\u003e3\\u003c/sub\\u003e\\u003csup\\u003e-\\u003c/sup\\u003e, 25.NO\\u003csub\\u003e2\\u003c/sub\\u003e\\u003csup\\u003e-\\u003c/sup\\u003e, 26.PO\\u003csub\\u003e4\\u003c/sub\\u003e\\u003csup\\u003e3-\\u003c/sup\\u003e, 27.HPO\\u003csub\\u003e4\\u003c/sub\\u003e\\u003csup\\u003e2-\\u003c/sup\\u003e, 28.H\\u003csub\\u003e2\\u003c/sub\\u003ePO\\u003csub\\u003e4\\u003c/sub\\u003e\\u003csup\\u003e-\\u003c/sup\\u003e, 29.CO\\u003csub\\u003e3\\u003c/sub\\u003e\\u003csup\\u003e2-\\u003c/sup\\u003e, 30.HCO\\u003csub\\u003e3\\u003c/sub\\u003e\\u003csup\\u003e-\\u003c/sup\\u003e, 31.Hg\\u003csup\\u003e2+\\u003c/sup\\u003e.)\\u003c/p\\u003e\",\"description\":\"\",\"filename\":\"image8.png\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-4019763/v1/78a1c43ffe386c1eb5f671d1.png\"},{\"id\":52449929,\"identity\":\"ca1f9e8d-214b-4824-b511-5d78c0165f2a\",\"added_by\":\"auto\",\"created_at\":\"2024-03-11 19:01:52\",\"extension\":\"png\",\"order_by\":9,\"title\":\"Figure 9\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":15064,\"visible\":true,\"origin\":\"\",\"legend\":\"\\u003cp\\u003eTime response experiments of probe \\u003cstrong\\u003eNXH \\u003c/strong\\u003e(10 µM) for Hg\\u003csup\\u003e2+\\u003c/sup\\u003e (0, 30, 50 µM) (\\u003cem\\u003eλ\\u003c/em\\u003e\\u003csub\\u003eex\\u003c/sub\\u003e = 425 nm)\\u003c/p\\u003e\",\"description\":\"\",\"filename\":\"image9.png\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-4019763/v1/dcd0eabfb3fa794d5cd2266c.png\"},{\"id\":52449930,\"identity\":\"1b4fd2d4-e6df-4060-9a86-f4a49b6ebbc4\",\"added_by\":\"auto\",\"created_at\":\"2024-03-11 19:01:52\",\"extension\":\"png\",\"order_by\":10,\"title\":\"Figure 10\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":12698,\"visible\":true,\"origin\":\"\",\"legend\":\"\\u003cp\\u003eThe pH effect experiments of probe \\u003cstrong\\u003eNXH \\u003c/strong\\u003e(10 µM) for Hg\\u003csup\\u003e2+\\u003c/sup\\u003e (50 µM) (\\u003cem\\u003eλ\\u003c/em\\u003e\\u003csub\\u003eex\\u003c/sub\\u003e = 425 nm)\\u003c/p\\u003e\",\"description\":\"\",\"filename\":\"image10.png\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-4019763/v1/897f02591c05c50ae0dcbbef.png\"},{\"id\":52450801,\"identity\":\"7ffe6562-bd25-4ea7-8d38-effede8a341b\",\"added_by\":\"auto\",\"created_at\":\"2024-03-11 19:09:52\",\"extension\":\"png\",\"order_by\":11,\"title\":\"Figure 11\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":14463,\"visible\":true,\"origin\":\"\",\"legend\":\"\\u003cp\\u003eReversibility experiments of probe \\u003cstrong\\u003eNXH \\u003c/strong\\u003e(10 µM) for Hg\\u003csup\\u003e2+\\u003c/sup\\u003e (50 µM) (\\u003cem\\u003eλ\\u003c/em\\u003e\\u003csub\\u003eex\\u003c/sub\\u003e = 425 nm)\\u003c/p\\u003e\",\"description\":\"\",\"filename\":\"image11.png\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-4019763/v1/a4eca9814e90cc492bddd096.png\"},{\"id\":52449935,\"identity\":\"2ebcc6f1-5984-4da9-9f4c-2d75e994d7c4\",\"added_by\":\"auto\",\"created_at\":\"2024-03-11 19:01:52\",\"extension\":\"png\",\"order_by\":12,\"title\":\"Figure 12\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":244889,\"visible\":true,\"origin\":\"\",\"legend\":\"\\u003cp\\u003eFluorescence changes of probe \\u003cstrong\\u003eNXH \\u003c/strong\\u003e(10 µM) for Hg\\u003csup\\u003e2+\\u003c/sup\\u003e (50 µM) under ultraviolet lamp\\u003c/p\\u003e\",\"description\":\"\",\"filename\":\"image12.png\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-4019763/v1/7c74d02c983ce78b6b19df26.png\"},{\"id\":52449943,\"identity\":\"2e1c1f46-cbb1-47ff-830a-d75a6f760a35\",\"added_by\":\"auto\",\"created_at\":\"2024-03-11 19:01:53\",\"extension\":\"png\",\"order_by\":13,\"title\":\"Figure 13\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":5651,\"visible\":true,\"origin\":\"\",\"legend\":\"\\u003cp\\u003e\\u003csup\\u003e1\\u003c/sup\\u003eH NMR spectra of probe \\u003cstrong\\u003eNXH \\u003c/strong\\u003e(10 µM) for Hg\\u003csup\\u003e2+\\u003c/sup\\u003e (50 µM)\\u003c/p\\u003e\",\"description\":\"\",\"filename\":\"image13.png\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-4019763/v1/b4ae0067d99060686798f26f.png\"},{\"id\":52449944,\"identity\":\"325fd9ac-a7a1-4dcf-b1f8-3229717ad7f4\",\"added_by\":\"auto\",\"created_at\":\"2024-03-11 19:01:53\",\"extension\":\"png\",\"order_by\":14,\"title\":\"Figure 14\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":46172,\"visible\":true,\"origin\":\"\",\"legend\":\"\\u003cp\\u003eThe mechanism of probe \\u003cstrong\\u003eNXH \\u003c/strong\\u003e(10 µM) for Hg\\u003csup\\u003e2+\\u003c/sup\\u003e (50 µM)\\u003c/p\\u003e\",\"description\":\"\",\"filename\":\"image14.png\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-4019763/v1/72546a4ef2ad207c898826ea.png\"},{\"id\":52449937,\"identity\":\"042d1586-f072-4f83-a64f-af60d60c081d\",\"added_by\":\"auto\",\"created_at\":\"2024-03-11 19:01:52\",\"extension\":\"png\",\"order_by\":15,\"title\":\"Figure 15\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":176335,\"visible\":true,\"origin\":\"\",\"legend\":\"\\u003cp\\u003eFluorescence imaging of probe \\u003cstrong\\u003eNXH \\u003c/strong\\u003e(10 µM) for Hg\\u003csup\\u003e2+\\u003c/sup\\u003e (50 µM) in tea samples under UV lamp (365 nm)\\u003c/p\\u003e\",\"description\":\"\",\"filename\":\"image15.png\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-4019763/v1/15b3afc01c483ef9e4cd4b4b.png\"},{\"id\":52449939,\"identity\":\"151ef4fb-dd02-4fb1-abe9-317aa536ddbf\",\"added_by\":\"auto\",\"created_at\":\"2024-03-11 19:01:52\",\"extension\":\"png\",\"order_by\":16,\"title\":\"Figure 16\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":81522,\"visible\":true,\"origin\":\"\",\"legend\":\"\\u003cp\\u003eThe \\u003cstrong\\u003eNXH \\u003c/strong\\u003etest paper treated different concentrations of Hg\\u003csup\\u003e2+\\u003c/sup\\u003e under ultraviolet lamp (365 nm)\\u003c/p\\u003e\",\"description\":\"\",\"filename\":\"image16.png\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-4019763/v1/963adc7ea766353df246110f.png\"},{\"id\":52449941,\"identity\":\"4302683c-7522-415f-9988-2a17a62824b7\",\"added_by\":\"auto\",\"created_at\":\"2024-03-11 19:01:53\",\"extension\":\"png\",\"order_by\":17,\"title\":\"Figure 17\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":160069,\"visible\":true,\"origin\":\"\",\"legend\":\"\\u003cp\\u003eFluorescence images of Hela cells. (a) Bright-field image of cells incubated with \\u003cstrong\\u003eNXH \\u003c/strong\\u003e(10 µM) for 30 min at 37 ℃; (b) Bright field images of \\u003cstrong\\u003eNXH\\u003c/strong\\u003e (10 µM) and Hg\\u003csup\\u003e2+\\u003c/sup\\u003e (30 µM) incubated for 30 min at 37℃; (c) Bright field images of \\u003cstrong\\u003eNXH\\u003c/strong\\u003e (10 µM) and Hg\\u003csup\\u003e2+\\u003c/sup\\u003e (50 µM) incubated for 30 min at 37℃; (d) Fluorescence image of (a); (e) Fluorescence image of (b); (f) Fluorescence image of (c)\\u003c/p\\u003e\",\"description\":\"\",\"filename\":\"image17.png\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-4019763/v1/6609bc7380c001cca2da7234.png\"},{\"id\":52452818,\"identity\":\"0a04258b-6855-452e-aabf-ec95ccebc97b\",\"added_by\":\"auto\",\"created_at\":\"2024-03-11 19:17:53\",\"extension\":\"pdf\",\"order_by\":0,\"title\":\"\",\"display\":\"\",\"copyAsset\":false,\"role\":\"manuscript-pdf\",\"size\":1955527,\"visible\":true,\"origin\":\"\",\"legend\":\"\",\"description\":\"\",\"filename\":\"manuscript.pdf\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-4019763/v1/92bc0855-8915-4033-b928-cffc3fd1c519.pdf\"},{\"id\":52449925,\"identity\":\"1a240ad4-e111-4ebd-b9ef-769d9dcea428\",\"added_by\":\"auto\",\"created_at\":\"2024-03-11 19:01:52\",\"extension\":\"png\",\"order_by\":1,\"title\":\"\",\"display\":\"\",\"copyAsset\":false,\"role\":\"supplement\",\"size\":105610,\"visible\":true,\"origin\":\"\",\"legend\":\"\\u003cp\\u003eScheme 1 Synthetic method of the target probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e\\u003c/p\\u003e\",\"description\":\"\",\"filename\":\"Scheme1.png\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-4019763/v1/fb27234f8b6ef709964a2fcd.png\"},{\"id\":52449932,\"identity\":\"f51dc789-b07a-49f8-8af6-b0f4af554c7f\",\"added_by\":\"auto\",\"created_at\":\"2024-03-11 19:01:52\",\"extension\":\"docx\",\"order_by\":2,\"title\":\"\",\"display\":\"\",\"copyAsset\":false,\"role\":\"supplement\",\"size\":1237832,\"visible\":true,\"origin\":\"\",\"legend\":\"\",\"description\":\"\",\"filename\":\"Supportinginformation.docx\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-4019763/v1/c3a7085e482bd6182b43ce9d.docx\"}],\"financialInterests\":\"No competing interests reported.\",\"formattedTitle\":\"A fluorescent probe for Hg 2+ specific recognition based on xanthene and its application in food detection and cell imaging\",\"fulltext\":[{\"header\":\"1. Introduction\",\"content\":\"\\u003cp\\u003eMercury (Hg) is the only element in the periodic table that has its own environmental convention, because of its serious harm to the environment and health, namely the Minamata Convention on Mercury\\u003csup\\u003e[\\u003cspan citationid=\\\"CR1\\\" class=\\\"CitationRef\\\"\\u003e1\\u003c/span\\u003e]\\u003c/sup\\u003e. It is also one of the \\\"10 Chemicals of Major Public Health Concern\\\" promulgated by the United Nations\\u003csup\\u003e[\\u003cspan citationid=\\\"CR2\\\" class=\\\"CitationRef\\\"\\u003e2\\u003c/span\\u003e]\\u003c/sup\\u003e.Mercury exists in many forms in the environment (elemental mercury, inorganic mercury and organic mercury), and no matter which form mercury exists, it will have toxic effects on mammals\\u003csup\\u003e[\\u003cspan citationid=\\\"CR3\\\" class=\\\"CitationRef\\\"\\u003e3\\u003c/span\\u003e, \\u003cspan citationid=\\\"CR4\\\" class=\\\"CitationRef\\\"\\u003e4\\u003c/span\\u003e]\\u003c/sup\\u003e. Mercury vapor is highly lipophilic and diffusible, it can easily cross the blood-brain barrier and cell membranes,and be oxidized into positive divalent mercury ions (Hg\\u003csup\\u003e2+\\u003c/sup\\u003e) in the cells, which will accumulate in the kidneys and brains over time. Inorganic mercury is rapidly converted into organic mercury (methylmercury) in ecosystems, and is enriched in the food chain as methylmercury, eventually entering the human body\\u003csup\\u003e[\\u003cspan additionalcitationids=\\\"CR6\\\" citationid=\\\"CR5\\\" class=\\\"CitationRef\\\"\\u003e5\\u003c/span\\u003e\\u0026ndash;\\u003cspan citationid=\\\"CR7\\\" class=\\\"CitationRef\\\"\\u003e7\\u003c/span\\u003e]\\u003c/sup\\u003e. The biological toxicity of mercury to humans is mainly manifested in inducing neuron death, damaging antioxidant and immune regulation functions, and destroying the normal functions of kidney and cardiovascular system\\u003csup\\u003e[\\u003cspan additionalcitationids=\\\"CR9 CR10 CR11\\\" citationid=\\\"CR8\\\" class=\\\"CitationRef\\\"\\u003e8\\u003c/span\\u003e\\u0026ndash;\\u003cspan citationid=\\\"CR12\\\" class=\\\"CitationRef\\\"\\u003e12\\u003c/span\\u003e]\\u003c/sup\\u003e.\\u003c/p\\u003e \\u003cp\\u003eThe detection of Hg\\u003csup\\u003e2+\\u003c/sup\\u003e has evolved from traditional instrumental analysis (such as spectrophotometry, high-performance liquid chromatography, and inductively coupled plasma emission spectrometry\\u003csup\\u003e[\\u003cspan additionalcitationids=\\\"CR14 CR15\\\" citationid=\\\"CR13\\\" class=\\\"CitationRef\\\"\\u003e13\\u003c/span\\u003e\\u0026ndash;\\u003cspan citationid=\\\"CR16\\\" class=\\\"CitationRef\\\"\\u003e16\\u003c/span\\u003e]\\u003c/sup\\u003e) to sensing detection in recent years. The sensing analysis method includes the advantages of the sensitivity and accuracy of the traditional detection method, and makes up for the shortcomings of the traditional detection in terms of cost investment, operation technology and practical application. Fluorescent probe sensing technology has been widely used in the detection of Hg\\u003csup\\u003e2+\\u003c/sup\\u003e in the environment and organisms due to its advantages of simple fabrication method, easy operation and and biologically non-destructive in situ imaging\\u003csup\\u003e[\\u003cspan additionalcitationids=\\\"CR18 CR19 CR20\\\" citationid=\\\"CR17\\\" class=\\\"CitationRef\\\"\\u003e17\\u003c/span\\u003e\\u0026ndash;\\u003cspan citationid=\\\"CR21\\\" class=\\\"CitationRef\\\"\\u003e21\\u003c/span\\u003e]\\u003c/sup\\u003e. As shown in Table \\u003cspan refid=\\\"MOESM1\\\" class=\\\"InternalRef\\\"\\u003eS1\\u003c/span\\u003e, according to the recognition mechanism of Hg\\u003csup\\u003e2+\\u003c/sup\\u003e, it can be mainly divided into two types of fluorescent probes: complexation probes \\u003csup\\u003e[\\u003cspan additionalcitationids=\\\"CR23\\\" citationid=\\\"CR22\\\" class=\\\"CitationRef\\\"\\u003e22\\u003c/span\\u003e\\u0026ndash;\\u003cspan citationid=\\\"CR24\\\" class=\\\"CitationRef\\\"\\u003e24\\u003c/span\\u003e]\\u003c/sup\\u003e and reaction probes \\u003csup\\u003e[\\u003cspan additionalcitationids=\\\"CR26\\\" citationid=\\\"CR25\\\" class=\\\"CitationRef\\\"\\u003e25\\u003c/span\\u003e\\u0026ndash;\\u003cspan citationid=\\\"CR27\\\" class=\\\"CitationRef\\\"\\u003e27\\u003c/span\\u003e]\\u003c/sup\\u003e. Complexation probes often be designed by introducing a recognition site with specific response to Hg\\u003csup\\u003e2+\\u003c/sup\\u003e into the probe molecule. Reaction probes often be designed based on Hg\\u003csup\\u003e2+\\u003c/sup\\u003e induced ring-opening reaction, desulfurization reaction and thioacetal deprotection.\\u003c/p\\u003e \\u003cp\\u003eThe xanthene molecule is formed by an oxygen bridge connecting two benzene rings, this molecular structure makes the xanthene have a good rigid plane. Meanwhile, the xanthene molecule also has good water solubility and low biological toxicity, which makes it an advantageous fluorophore for the construction of fluorescent detection probes in vivo\\u003csup\\u003e[\\u003cspan additionalcitationids=\\\"CR29\\\" citationid=\\\"CR28\\\" class=\\\"CitationRef\\\"\\u003e28\\u003c/span\\u003e\\u0026ndash;\\u003cspan citationid=\\\"CR30\\\" class=\\\"CitationRef\\\"\\u003e30\\u003c/span\\u003e]\\u003c/sup\\u003e.\\u003c/p\\u003e \\u003cp\\u003eBased on the above-mentioned investigation of the structure design of the specific recognition of Hg\\u003csup\\u003e2+\\u003c/sup\\u003e fluorescent probe (as shown in Table \\u003cspan refid=\\\"MOESM1\\\" class=\\\"InternalRef\\\"\\u003eS1\\u003c/span\\u003e), in this paper, xanthene was used as the fluorophore and the mercury-philic sulfur-containing group aminothiourea was used as the response group to construct the mercury coordination fluorescent probe \\u003cb\\u003eNXH\\u003c/b\\u003e. Due to the low toxicity and good biocompatibility of anthracene fluorophore, fluorescent probe \\u003cb\\u003eNXH\\u003c/b\\u003e is expected to realize the qualitative and quantitative detection of Hg\\u003csup\\u003e2+\\u003c/sup\\u003e in environment and organism.\\u003c/p\\u003e \\u003cp\\u003e \\u003c/p\\u003e\"},{\"header\":\"2. Experiment\",\"content\":\"\\u003cdiv id=\\\"Sec3\\\" class=\\\"Section2\\\"\\u003e\\n\\u003ch2\\u003e2.1 Materials and methods\\u003c/h2\\u003e\\n\\u003cp\\u003eThe reagents we used were all analytical purity purchased from suppliers, and no further purification was needed. Please refer to the supporting information for the preparation of specific reserve liquid and instrument information.\\u003c/p\\u003e\\n\\u003c/div\\u003e\\n\\u003cdiv id=\\\"Sec4\\\" class=\\\"Section2\\\"\\u003e\\n\\u003ch2\\u003e2.2 Synthesis\\u003c/h2\\u003e\\n\\u003cp\\u003eThe detailed method of synthesis of intermediate \\u003cstrong\\u003eXn2\\u003c/strong\\u003e can be found in the supporting information.\\u003c/p\\u003e\\n\\u003cp\\u003eSynthesis of target probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e: \\u003cstrong\\u003eXn2\\u003c/strong\\u003e (0.31 g, 1.3 mmol) and aminothiourea (0.12 g, 1.3 mmol) were dissolved in 10 mL of absolute ethanol, and the reaction system was heated and refluxed in N\\u003csub\\u003e2\\u003c/sub\\u003e atmosphere for 7 h, and TLC was used to monitor the reaction process. After the reaction is completed, it was cooled to room temperature, three times the amount of ice water was poured in, and the orange-brown solid precipitated, filtered, washed, and dried to obtain crude \\u003cstrong\\u003eNXH\\u003c/strong\\u003e. The obtained crude product was purified by silica gel column chromatography (eluent: V \\u003csub\\u003epetroleum ether\\u003c/sub\\u003e: V \\u003csub\\u003eethyl acetate\\u003c/sub\\u003e = 3:1) to obtain pure \\u003cstrong\\u003eNXH\\u003c/strong\\u003e.\\u003c/p\\u003e\\n(\\u003cem\\u003eZ\\u003c/em\\u003e)-2-((6-methoxy-2,3-dihydro-1\\u003cem\\u003eH\\u003c/em\\u003e-xanthen-4-yl)methylene)hydrazine-1-carbothioamide (\\u003cstrong\\u003eNXH\\u003c/strong\\u003e): orange brown solid in yield 72.4%, m.p.m.p. 182.7\\u0026thinsp;~\\u0026thinsp;183.4 ℃, IR (KBr) \\u003cem\\u003e\\u0026nu;\\u003c/em\\u003e / cm\\u003csup\\u003e\\u0026minus;\\u0026thinsp;1\\u003c/sup\\u003e :3305, 3280, 3030, 2680, 1740, 1605, 1275. \\u003csup\\u003e1\\u003c/sup\\u003eH NMR (400 MHz, DMSO-\\u003cem\\u003ed\\u003c/em\\u003e\\u003csub\\u003e6\\u003c/sub\\u003e) \\u0026delta; 11.17 (s, 2H), 8.17 (s, 1H), 7.99 (s, 1H),7.01 (s, 1H), 6.62 (s, 1H), 6.61 (s, 1H), 5.32 (s, 1H), 3.74 (d, \\u003cem\\u003eJ\\u003c/em\\u003e\\u0026thinsp;=\\u0026thinsp;3.0 Hz, 3H), 2.68 (d, \\u003cem\\u003eJ\\u003c/em\\u003e\\u0026thinsp;=\\u0026thinsp;1.7 Hz, 2H), 2.66 (s, 2H), 1.46\\u0026ndash;1.45 (m, 2H). \\u003csup\\u003e13\\u003c/sup\\u003eC NMR (101 MHz, DMSO-\\u003cem\\u003ed6\\u003c/em\\u003e) \\u0026delta; 22.70, 29.10, 30.92, 55.39, 100.00, 108.48, 108.86, 109.38, 121.52, 129.66, 140.20, 144.16, 153.02, 153.13, 160.22, 180.87. HRMS (positive-ESIMS) calcd for C\\u003csub\\u003e16\\u003c/sub\\u003eH\\u003csub\\u003e17\\u003c/sub\\u003eN\\u003csub\\u003e3\\u003c/sub\\u003eO\\u003csub\\u003e2\\u003c/sub\\u003eS [M\\u0026thinsp;+\\u0026thinsp;H]\\u003csup\\u003e+\\u003c/sup\\u003e 316.1058, found 316.1014.\\u003c/div\\u003e\"},{\"header\":\"3. Results and discussion\",\"content\":\"\\u003cdiv id=\\\"Sec6\\\" class=\\\"Section2\\\"\\u003e\\n\\u003ch2\\u003e3.1 Ultraviolet titration experiments\\u003c/h2\\u003e\\n\\u003cp\\u003eHg\\u003csup\\u003e2+\\u003c/sup\\u003e with different concentrations (0,10,20,30,40,50 \\u0026micro;M) were added into the \\u003cstrong\\u003eNXH\\u003c/strong\\u003e solution (10 \\u0026micro;M) for ultraviolet titration experiment. The ultraviolet absorption spectra corresponding to different concentrations of mercury ions were recorded respectively. As shown in Fig.\\u0026nbsp;\\u003cspan class=\\\"InternalRef\\\"\\u003e2\\u003c/span\\u003e, the probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e solution has two maximum ultraviolet absorption peaks, which were located at 300 nm and 425 nm respectively. With the addition of Hg\\u003csup\\u003e2+\\u003c/sup\\u003e (0\\u0026thinsp;~\\u0026thinsp;50 \\u0026micro;M), the ultraviolet absorption peak gradually increases, which means that the probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e is responsive to Hg\\u003csup\\u003e2+\\u003c/sup\\u003e.\\u003c/p\\u003e\\n\\u003c/div\\u003e\\n\\u003cdiv id=\\\"Sec7\\\" class=\\\"Section2\\\"\\u003e\\n\\u003ch2\\u003e3.2 Fluorescence titration experiments\\u003c/h2\\u003e\\n\\u003cp\\u003eDifferent concentrations of Hg\\u003csup\\u003e2+\\u003c/sup\\u003e (0, 5, 10, 15, 20, 30, 40, 50 \\u0026micro;M) were adde into probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e solution (10 \\u0026micro;M), and the fluorescence spectrum at corresponding Hg\\u003csup\\u003e2+\\u003c/sup\\u003e concentration was recorded. As shown in Fig.\\u0026nbsp;\\u003cspan class=\\\"InternalRef\\\"\\u003e3\\u003c/span\\u003ea, the probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e solution itself has a strong fluorescence emission at 545 nm with an intensity of 2352 a.u. With the addition of (0\\u0026thinsp;~\\u0026thinsp;50 \\u0026micro;M) Hg\\u003csup\\u003e2+\\u003c/sup\\u003e, the fluorescence intensity of \\u003cstrong\\u003eNXH\\u003c/strong\\u003e-Hg\\u003csup\\u003e2+\\u003c/sup\\u003e solution system was gradually quenched to about 308 a.u, showing a significant \\\"turn-off\\\" phenomenon.\\u003c/p\\u003e\\n\\u003cp\\u003eIn order to calculate the sensitivity of probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e to Hg\\u003csup\\u003e2+\\u003c/sup\\u003e detection, the linear curve was drawn with the fluorescence intensity of probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e at 545 nm as the ordinate and the concentration of Hg\\u003csup\\u003e2+\\u003c/sup\\u003e as the abscissa. As shown in Fig.\\u0026nbsp;\\u003cspan class=\\\"InternalRef\\\"\\u003e3\\u003c/span\\u003eb, there has a good linear relationship between them, and the linear regression equation is Y = -40.17401 X\\u0026thinsp;+\\u0026thinsp;2304.52099 and the linear determination coefficient is R\\u003csup\\u003e2\\u003c/sup\\u003e\\u0026thinsp;=\\u0026thinsp;0.99047. According to the detection limit calculation formula: LOD\\u0026thinsp;=\\u0026thinsp;3\\u0026sigma;/k (where \\u0026sigma; is the standard deviation of the blank measurement, and k is the slope)\\u003csup\\u003e[\\u003cspan class=\\\"CitationRef\\\"\\u003e31\\u003c/span\\u003e]\\u003c/sup\\u003e, the detection limits of the probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e for Hg\\u003csup\\u003e2+\\u003c/sup\\u003e was determined to be 96.3 nM. To sum up, the fluorescent probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e has high sensitivity for the detection of Hg\\u003csup\\u003e2+\\u003c/sup\\u003e.\\u003c/p\\u003e\\n\\u003cp\\u003eThe fluorescence color of probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e was predicted by CIE chromaticity diagram. As shown in Fig.\\u0026nbsp;\\u003cspan class=\\\"InternalRef\\\"\\u003e4\\u003c/span\\u003e, the CIE coordinates of the probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e correspond to the yellow area of the chromaticity disk, and it was speculated that the probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e solution may emit photochromic fluorescence. To verify the above speculation, the fluorescence color of the probe solution in the presence of different concentrations of Hg\\u003csup\\u003e2+\\u003c/sup\\u003e (0\\u0026thinsp;~\\u0026thinsp;50 \\u0026micro;M) was observed under ultraviolet lamp (365 nm). As shown in Fig.\\u0026nbsp;\\u003cspan class=\\\"InternalRef\\\"\\u003e5\\u003c/span\\u003e, \\u003cstrong\\u003eNXH\\u003c/strong\\u003e solution emits strong yellowish fluorescence, and with the increase of Hg\\u003csup\\u003e2+\\u003c/sup\\u003e concentration, the fluorescence intensity of the solution gradually weakened to almost no light. The fluorescence of probe solution changes obviously in the presence of different concentrations of Hg\\u003csup\\u003e2+\\u003c/sup\\u003e, which preliminarily shows that probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e has certain practical application potential.\\u003c/p\\u003e\\n\\u003c/div\\u003e\\n\\u003cdiv id=\\\"Sec8\\\" class=\\\"Section2\\\"\\u003e\\n\\u003ch2\\u003e3.3 Complexometric titration experiments\\u003c/h2\\u003e\\nThe complexation constant Ka of probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e to Hg\\u003csup\\u003e2+\\u003c/sup\\u003e was calculated by using the benzene-hildebrand equation (B-H equation). As shown in Fig.\\u0026nbsp;\\u003cspan class=\\\"InternalRef\\\"\\u003e6\\u003c/span\\u003e, \\u003cspan class=\\\"InternalRef\\\"\\u003e1\\u003c/span\\u003e/[Hg\\u003csup\\u003e2+\\u003c/sup\\u003e] was selected as the abscissa (Hg\\u003csup\\u003e2+\\u003c/sup\\u003e concentrations are 5, 10, 15, 20, 30, 40 and 50 \\u0026micro;M, respectively), and 1/(F-F\\u003csub\\u003emin\\u003c/sub\\u003e) was selected as the ordinate (F\\u003csub\\u003emin\\u003c/sub\\u003e and F represent fluorescence intensity values corresponding to Hg\\u003csup\\u003e2+\\u003c/sup\\u003e concentrations of 0 and 5\\u0026thinsp;~\\u0026thinsp;50 \\u0026micro;M, respectively). There has a good linear relationship between them, and the linear determination coefficient is R\\u003csup\\u003e2\\u003c/sup\\u003e\\u0026thinsp;=\\u0026thinsp;0.99882. According to the B-H equation, the complexation constant is 1.1\\u0026times;10\\u003csup\\u003e4\\u003c/sup\\u003e M\\u003csup\\u003e\\u0026minus;\\u0026thinsp;1\\u003c/sup\\u003e, which shows that the probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e has strong complexation ability to Hg\\u003csup\\u003e2+\\u003c/sup\\u003e.\\u003c/div\\u003e\\n\\u003cdiv id=\\\"Sec9\\\" class=\\\"Section2\\\"\\u003e\\n\\u003ch2\\u003e3.4 Selective experiments\\u003c/h2\\u003e\\n\\u003cp\\u003eTo explore the specificity of \\u003cstrong\\u003eNXH\\u003c/strong\\u003e for Hg\\u003csup\\u003e2+\\u003c/sup\\u003e recognition, thirty representative analytes, such as Na\\u003csup\\u003e+\\u003c/sup\\u003e, Al\\u003csup\\u003e3+\\u003c/sup\\u003e, K\\u003csup\\u003e+\\u003c/sup\\u003e, Ag\\u003csup\\u003e+\\u003c/sup\\u003e,Ca\\u003csup\\u003e2+\\u003c/sup\\u003e, Mg\\u003csup\\u003e2+\\u003c/sup\\u003e, Zn\\u003csup\\u003e2+\\u003c/sup\\u003e, Fe\\u003csup\\u003e2+\\u003c/sup\\u003e, Fe\\u003csup\\u003e3+\\u003c/sup\\u003e, Sn\\u003csup\\u003e2+\\u003c/sup\\u003e, Pb\\u003csup\\u003e2+\\u003c/sup\\u003e, Cu\\u003csup\\u003e2+\\u003c/sup\\u003e, Ba\\u003csup\\u003e2+\\u003c/sup\\u003e, Ga\\u003csup\\u003e3+\\u003c/sup\\u003e, Ni\\u003csup\\u003e2+\\u003c/sup\\u003e, Hg\\u003csup\\u003e2+\\u003c/sup\\u003e, F\\u003csup\\u003e\\u0026minus;\\u003c/sup\\u003e, Cl\\u003csup\\u003e\\u0026minus;\\u003c/sup\\u003e, Br\\u003csup\\u003e\\u0026minus;\\u003c/sup\\u003e, I\\u003csup\\u003e\\u0026minus;\\u003c/sup\\u003e, SO\\u003csub\\u003e4\\u003c/sub\\u003e\\u003csup\\u003e2\\u0026minus;\\u003c/sup\\u003e, HSO\\u003csub\\u003e3\\u003c/sub\\u003e\\u003csup\\u003e\\u0026minus;\\u003c/sup\\u003e, SO\\u003csub\\u003e3\\u003c/sub\\u003e\\u003csup\\u003e2\\u0026minus;\\u003c/sup\\u003e, NO\\u003csub\\u003e3\\u003c/sub\\u003e\\u003csup\\u003e\\u0026minus;\\u003c/sup\\u003e, NO\\u003csub\\u003e2\\u003c/sub\\u003e\\u003csup\\u003e\\u0026minus;\\u003c/sup\\u003e, PO\\u003csub\\u003e4\\u003c/sub\\u003e\\u003csup\\u003e3\\u0026minus;\\u003c/sup\\u003e, HPO\\u003csub\\u003e4\\u003c/sub\\u003e\\u003csup\\u003e2\\u0026minus;\\u003c/sup\\u003e, H\\u003csub\\u003e2\\u003c/sub\\u003ePO\\u003csub\\u003e4\\u003c/sub\\u003e\\u003csup\\u003e\\u0026minus;\\u003c/sup\\u003e, CO\\u003csub\\u003e3\\u003c/sub\\u003e\\u003csup\\u003e2\\u0026minus;\\u003c/sup\\u003e and HCO\\u003csub\\u003e3\\u003c/sub\\u003e\\u003csup\\u003e\\u0026minus;\\u003c/sup\\u003e were selected for selectivity experiments. As shown in Fig.\\u0026nbsp;\\u003cspan class=\\\"InternalRef\\\"\\u003e7\\u003c/span\\u003e, the probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e solution (10 \\u0026micro;M) had a strong fluorescence emission at 545 nm, and when the above 29 analyte solutions (50 \\u0026micro;M) were added to the probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e solution (10 \\u0026micro;M), the fluorescence intensity has no obvious change. Only when Hg\\u003csup\\u003e2+\\u003c/sup\\u003e (50 \\u0026micro;M) was added, the fluorescence intensity of the solution decreases greatly. It shows that the response of probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e to Hg\\u003csup\\u003e2+\\u003c/sup\\u003e is specific.\\u003c/p\\u003e\\n\\u003c/div\\u003e\\n\\u003cdiv id=\\\"Sec10\\\" class=\\\"Section2\\\"\\u003e\\n\\u003ch2\\u003e3.5 Interference experiments\\u003c/h2\\u003e\\n\\u003cp\\u003eTo test whether the detection of Hg\\u003csup\\u003e2+\\u003c/sup\\u003e by probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e will be interfered by other ions, the anti-interference experiments was conducted, and the results were shown in Fig.\\u0026nbsp;\\u003cspan class=\\\"InternalRef\\\"\\u003e8\\u003c/span\\u003e. When only interfering substances were added, the fluorescence of the solution system did not change obviously. On this basis, the fluorescence intensity of the solution was greatly quenched by adding Hg\\u003csup\\u003e2+\\u003c/sup\\u003e (50 \\u0026micro;M), which was close to the fluorescence intensity when only Hg\\u003csup\\u003e2+\\u003c/sup\\u003e was added to the probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e solution. It shows that the recognition of Hg\\u003csup\\u003e2+\\u003c/sup\\u003e by \\u003cstrong\\u003eNXH\\u003c/strong\\u003e will not be interfered by other ions, and it can be used for the detection of Hg\\u003csup\\u003e2+\\u003c/sup\\u003e in real environment.\\u003c/p\\u003e\\n\\u003c/div\\u003e\\n\\u003cdiv id=\\\"Sec11\\\" class=\\\"Section2\\\"\\u003e\\n\\u003ch2\\u003e3.6 Time response experiments\\u003c/h2\\u003e\\n\\u003cp\\u003eWe carried out time response experiments to evaluate the real-time detection ability of probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e for Hg\\u003csup\\u003e2+\\u003c/sup\\u003e. As shown in Fig.\\u0026nbsp;\\u003cspan class=\\\"InternalRef\\\"\\u003e9\\u003c/span\\u003e, when adding 30 \\u0026micro;M and 50 \\u0026micro;M Hg\\u003csup\\u003e2+\\u003c/sup\\u003e to probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e solution (10 \\u0026micro;M) respectively, similar phenomena was observed, The fluorescence intensity of the solution decreased to the lowest within 105 s, and then remained stable. It shows that the probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e can quickly identify Hg\\u003csup\\u003e2+\\u003c/sup\\u003e within 105 s.\\u003c/p\\u003e\\n\\u003c/div\\u003e\\n\\u003cdiv id=\\\"Sec12\\\" class=\\\"Section2\\\"\\u003e\\n\\u003ch2\\u003e3.7 pH effect experiments\\u003c/h2\\u003e\\n\\u003cp\\u003eIn order to test the pH application range of probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e, the pH dependence experiments were carried out. As shown in Fig.\\u0026nbsp;\\u003cspan class=\\\"InternalRef\\\"\\u003e10\\u003c/span\\u003e, the fluorescence intensity of probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e was not affected in the range of pH\\u0026thinsp;=\\u0026thinsp;1.1\\u0026thinsp;~\\u0026thinsp;12.1. When pH\\u0026thinsp;\\u0026gt;\\u0026thinsp;9.3, the fluorescence intensity of the \\u003cstrong\\u003eNXH\\u003c/strong\\u003e-Hg\\u003csup\\u003e2+\\u003c/sup\\u003e solution system increased slightly. The optimum pH range for probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e to recognize Hg\\u003csup\\u003e2+\\u003c/sup\\u003e is pH\\u0026thinsp;=\\u0026thinsp;2.1\\u0026thinsp;~\\u0026thinsp;9.3, including physiological pH range. Therefore, it can be considered to recognize Hg\\u003csup\\u003e2+\\u003c/sup\\u003e in organisms.\\u003c/p\\u003e\\n\\u003c/div\\u003e\\n\\u003cdiv id=\\\"Sec13\\\" class=\\\"Section2\\\"\\u003e\\n\\u003ch2\\u003e3.8 Reversibility experiments\\u003c/h2\\u003e\\n\\u003cp\\u003eThe repeatability of probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e for Hg\\u003csup\\u003e2+\\u003c/sup\\u003e detection was evaluated by using EDTA as Hg\\u003csup\\u003e2+\\u003c/sup\\u003e scavenger. As shown in Fig.\\u0026nbsp;\\u003cspan class=\\\"InternalRef\\\"\\u003e11\\u003c/span\\u003e, the same amount of Hg\\u003csup\\u003e2+\\u003c/sup\\u003e and EDTA were alternately added to the probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e solution (10 \\u0026micro;M), it can be observed that the fluorescence signal of the solution appears 4 times alternating \\\"on-off-on\\\" phenomenon. And the fluorescence changes of the solution system corresponding to the above phenomena can be observed under the ultraviolet lamp (365 nm) (as shown in Fig.\\u0026nbsp;\\u003cspan class=\\\"InternalRef\\\"\\u003e12\\u003c/span\\u003e), indicating that the \\u003cstrong\\u003eNXH\\u003c/strong\\u003e has good reusability for the detection of Hg\\u003csup\\u003e2+\\u003c/sup\\u003e.\\u003c/p\\u003e\\n\\u003cp\\u003e\\u0026nbsp;\\u003c/p\\u003e\\n\\u003c/div\\u003e\\n\\u003ch2\\u003e3.9 Mechanism exploration experiments\\u003c/h2\\u003e\\n\\u003cp id=\\\"Sec14\\\" class=\\\"Section2\\\"\\u003eFirstly, the Job's curve was drawn to determine the coordination ratio of \\u003cstrong\\u003eNXH\\u003c/strong\\u003e and Hg\\u003csup\\u003e2+\\u003c/sup\\u003e. As shown in Fig. S4, when the ratio of [Hg\\u003csup\\u003e2+\\u003c/sup\\u003e]/[Hg\\u003csup\\u003e2+\\u003c/sup\\u003e + \\u003cstrong\\u003eNXH\\u003c/strong\\u003e] is 0.33, that is, the ratio of \\u003cstrong\\u003eNXH\\u003c/strong\\u003e to Hg\\u003csup\\u003e2+\\u003c/sup\\u003e is 2: 1, the fluorescence intensity of the solution system is the minimum.\\u003c/p\\u003e\\n\\u003cp class=\\\"Section2\\\"\\u003eHRMS titration experiments was used to further determine the complexation ratio of \\u003cstrong\\u003eNXH\\u003c/strong\\u003e and Hg\\u003csup\\u003e2+\\u003c/sup\\u003e. As shown in Fig. S5, Before adding Hg\\u003csup\\u003e2+\\u003c/sup\\u003e, a signal peak consistent with the expected molecular weight of probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e was generated at 316.1014. After adding Hg\\u003csup\\u003e2+\\u003c/sup\\u003e, the new signal peak at 831.0861 was similar to the molecular weight of the complex formed by \\u003cstrong\\u003eNXH\\u003c/strong\\u003e and Hg\\u003csup\\u003e2+\\u003c/sup\\u003e in a 2:1 ratio.\\u003c/p\\u003e\\n\\u003cp class=\\\"Section2\\\"\\u003eNext, the \\u003csup\\u003e1\\u003c/sup\\u003eH NMR titration experiments was used to determine the binding site of probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e and Hg\\u003csup\\u003e2+\\u003c/sup\\u003e. As shown in Fig.\\u0026nbsp;\\u003cspan class=\\\"InternalRef\\\"\\u003e13\\u003c/span\\u003e, it was found that after the addition of Hg\\u003csup\\u003e2+\\u003c/sup\\u003e, only the characteristic H belonging to imine disappeared in the probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e molecule.\\u003c/p\\u003e\\n\\u003cp class=\\\"Section2\\\"\\u003eBased on Gaussian 09 program, the B3LYP/ 6-311\\u0026thinsp;+\\u0026thinsp;+\\u0026thinsp;G (d, p) method, density functional theory calculation was used to explain the fluorescence change of Hg\\u003csup\\u003e2+\\u003c/sup\\u003e recognized by \\u003cstrong\\u003eNXH\\u003c/strong\\u003e. As shown in Fig. S6. The highest occupancy orbital (HOMO) of the complex \\u003cstrong\\u003eNXH\\u003c/strong\\u003e-Hg\\u003csup\\u003e2+\\u003c/sup\\u003e was mainly distributed in the xanthene fluorophore, partly in the ligand, while the lowest empty orbital (LUMO) was completely distributed on the ligand, away from the fluorophore, and there was a flow of electrons migrating from the fluorophore to the ligand, which was contrary to the fluorescence production mechanism. In addition, according to the energy gap value calculation formula:\\u003c/p\\u003e\\n\\u003cp\\u003eEgap\\u0026thinsp;=\\u0026thinsp;LUMO - HOMO\\u003c/p\\u003e\\n\\u003cp\\u003eThe calculated energy gap values of \\u003cstrong\\u003eNXH\\u003c/strong\\u003e and \\u003cstrong\\u003eNXH\\u003c/strong\\u003e-Hg\\u003csup\\u003e2+\\u003c/sup\\u003e were 0.11237 a.u. and 0.22482 a.u., respectively. Obviously, the energy gap value of \\u003cstrong\\u003eNXH\\u003c/strong\\u003e-Hg\\u003csup\\u003e2+\\u003c/sup\\u003e is larger, and generally, the larger energy gap value is not conducive to the generation of fluorescence signals. To sum up, the mechanism of Hg\\u003csup\\u003e2+\\u003c/sup\\u003e recognition by probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e was shown in Fig.\\u0026nbsp;\\u003cspan class=\\\"InternalRef\\\"\\u003e14\\u003c/span\\u003e.\\u003c/p\\u003e\\n\\u003cp\\u003e\\u0026nbsp;\\u003c/p\\u003e\\n\\u003cdiv id=\\\"Sec15\\\" class=\\\"Section2\\\"\\u003e\\n\\u003ch2\\u003e3.10 Practical applications\\u003c/h2\\u003e\\n\\u003ch2\\u003e3.10.1 Tea samples\\u003c/h2\\u003e\\n\\u003cp id=\\\"Sec16\\\" class=\\\"Section3\\\"\\u003eFood is one of the main ways for human body to ingest mercury ions. Therefore, three tea samples, Jinjunmei, Biluochun and Qimen Hongcha were selected to evaluate the ability of the probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e to detect Hg\\u003csup\\u003e2+\\u003c/sup\\u003e in food samples. The tea samples were pre-treated by placing 0.5 g of crushed tea in 20 mL of concentrated nitric acid and soaking overnight. and After dissolution and centrifugation, the pH of the sample was adjusted to be neutral with sodium hydroxide solution. The fluorescence changes of the \\u003cstrong\\u003eNXH\\u003c/strong\\u003e-tea sample after adding Hg\\u003csup\\u003e2+\\u003c/sup\\u003e were observed under UV light (365 nm). As shown in Fig.\\u0026nbsp;\\u003cspan class=\\\"InternalRef\\\"\\u003e15\\u003c/span\\u003e, the sample solutions pretreated with probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e emitted bright yellow fluorescence, and the solutions were quenched to almost no fluorescence after the addition of Hg\\u003csup\\u003e2+\\u003c/sup\\u003e, which suggests that the probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e has the ability to qualitatively detect Hg\\u003csup\\u003e2+\\u003c/sup\\u003e in food samples.\\u003c/p\\u003e\\n\\u003cp class=\\\"Section3\\\"\\u003eThe standard addition recovery method was used to measure the ability of probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e to quantitatively detect Hg\\u003csup\\u003e2+\\u003c/sup\\u003e in tea samples. Add 15, 30 and \\u0026micro;M Hg\\u003csup\\u003e2+\\u003c/sup\\u003e to the tea samples respectively, and calculate the detected concentration of Hg\\u003csup\\u003e2+\\u003c/sup\\u003e in the solution by combining the linear regression equation Y = -40.17401 X\\u0026thinsp;+\\u0026thinsp;2304.520991 obtained from the fluorescence titration experiment in 3.2. As shown in Table S2, the recovery rate of Hg\\u003csup\\u003e2+\\u003c/sup\\u003e in the three tea samples was maintained at 99.47\\u0026thinsp;~\\u0026thinsp;102.87%, and the RSD values of each group of data were less than 1.83%. It indicating that the probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e can quantitative detection of Hg\\u003csup\\u003e2+\\u003c/sup\\u003e in the tea samples.\\u003c/p\\u003e\\n\\u003cdiv id=\\\"Sec17\\\" class=\\\"Section3\\\"\\u003e\\n\\u003ch2\\u003e3.10.2 Fluorescence test paper\\u003c/h2\\u003e\\nIn view of the application potential of the fluorescent probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e for the detection of Hg\\u003csup\\u003e2+\\u003c/sup\\u003e in food samples and the excellent performance of Hg\\u003csup\\u003e2+\\u003c/sup\\u003e detection, the probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e was tried to be made into test paper. Dropping different concentrations of Hg\\u003csup\\u003e2+\\u003c/sup\\u003e solution onto the surface of the test paper, the phenomenon shown in Fig.\\u0026nbsp;\\u003cspan class=\\\"InternalRef\\\"\\u003e16\\u003c/span\\u003e can be observed under the ultraviolet lamp (365 nm). With the increase of Hg\\u003csup\\u003e2+\\u003c/sup\\u003e concentration, the fluorescence on the surface of the test paper gradually weakened to almost disappear, indicating that the fluorescence detection test paper made of probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e can qualitatively identify Hg\\u003csup\\u003e2+\\u003c/sup\\u003e.\\u003c/div\\u003e\\n\\u003cdiv id=\\\"Sec18\\\" class=\\\"Section3\\\"\\u003e\\n\\u003ch2\\u003e3.10.3 Cell imaging\\u003c/h2\\u003e\\n\\u003cp\\u003eIt is of great significance to detect the level of Hg\\u003csup\\u003e2+\\u003c/sup\\u003e in organisms, so we try to apply the probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e to the biological imaging detection of Hg\\u003csup\\u003e2+\\u003c/sup\\u003e. As shown in Fig. S7, the cell viability of Hela cells remained above 83% after 24 hours of treatment with different concentrations of probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e solution, indicating that the probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e has low cytotoxicity.\\u003c/p\\u003e\\n\\u003cp\\u003eAs shown in Fig.\\u0026nbsp;\\u003cspan class=\\\"InternalRef\\\"\\u003e17\\u003c/span\\u003e, when cells were incubated with probe \\u003cstrong\\u003eNXH\\u003c/strong\\u003e (10 \\u0026micro;M) for 30 min, strong green fluorescence was observed (Fig.\\u0026nbsp;\\u003cspan class=\\\"InternalRef\\\"\\u003e17\\u003c/span\\u003ed). After incubation with 30 \\u0026micro;M Hg\\u003csup\\u003e2+\\u003c/sup\\u003e for 30 min, the green fluorescence observed in the cells weakened, and the concentration of Hg\\u003csup\\u003e2+\\u003c/sup\\u003e increased to 50 \\u0026micro;M, almost no fluorescence could be seen in the cells (Fig.\\u0026nbsp;\\u003cspan class=\\\"InternalRef\\\"\\u003e17\\u003c/span\\u003ef).\\u003c/p\\u003e\\n\\u003c/div\\u003e\\n\\u003c/div\\u003e\"},{\"header\":\"4. Conclusion\",\"content\":\"\\u003cp\\u003eThe mercury-philic aminothiourea group was introduced into the xanthene fluorophore, and a fluorescent probe \\u003cb\\u003eNXH\\u003c/b\\u003e with specific response to Hg\\u003csup\\u003e2+\\u003c/sup\\u003e was developed. \\u003cb\\u003eNXH\\u003c/b\\u003e recognizes Hg\\u003csup\\u003e2+\\u003c/sup\\u003e by fluorescence quenching. When (0\\u0026thinsp;~\\u0026thinsp;50 \\u0026micro;M) Hg\\u003csup\\u003e2+\\u003c/sup\\u003e was added to the probe solution, the fluorescence intensity of the solution was negatively correlated with the concentration of Hg\\u003csup\\u003e2+\\u003c/sup\\u003e added. The probe \\u003cb\\u003eNXH\\u003c/b\\u003e has a wide pH range (2.1\\u0026thinsp;~\\u0026thinsp;9.3), fast response speed (105 s) and high sensitivity (LOD\\u0026thinsp;=\\u0026thinsp;96.3 nM), which has a good application prospect. The probe \\u003cb\\u003eNXH\\u003c/b\\u003e has been successfully used to make Hg\\u003csup\\u003e2+\\u003c/sup\\u003e test strips and can fluorescently identify Hg\\u003csup\\u003e2+\\u003c/sup\\u003e in tea samples and biological cells.\\u003c/p\\u003e\"},{\"header\":\"Declarations\",\"content\":\"\\u003cp\\u003e \\u003ch2\\u003eCompeting Interests\\u003c/h2\\u003e \\u003cp\\u003eThere are no conflicts of interest.\\u003c/p\\u003e \\u003c/p\\u003e\\u003cp\\u003e \\u003ch2\\u003eEthical Approval\\u003c/h2\\u003e \\u003cp\\u003eThis article does not contain any studies involving human participants performed by any of the authors.\\u003c/p\\u003e \\u003c/p\\u003e\\u003ch2\\u003eFunding\\u003c/h2\\u003e \\u003cp\\u003eNo funding, grants, or other support was received during the preparation of this manuscript.\\u003c/p\\u003e\\u003ch2\\u003eAuthor Contribution\\u003c/h2\\u003e\\u003cp\\u003eC L-Z:Investigation, Writing - review \\u0026amp; editing, Methodology;S R-N:Investigation, Conceptualization, Writing - original draft, Formal analysis;C-L:Investigation, Formal analysis;Y-Z:Investigation, Formal analysis;J H-G::Investigation, Formal analysis;All authors reviewed the manuscript.\\u003c/p\\u003e\\u003ch2\\u003eData Availability\\u003c/h2\\u003e \\u003cp\\u003eThe data generated and analyzed will be made available upon reasonable request from the corresponding authors.\\u003c/p\\u003e\"},{\"header\":\"References\",\"content\":\"\\u003col\\u003e\\u003cli\\u003e\\u003cspan\\u003eCoulter M (2014) The Minamata Convention On Mercury: Past, Present, And Future Environmental Health[J]. Sustainable Dev Law Policy 14:12\\u0026ndash;13\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eJain J, Gauba P (2017) Heavy metal toxicity-implications on metabolism and health[J]. Int J pharma Bio Sci 8(4):452\\u0026ndash;460\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eClifton JC (2007) Mercury Exposure and Public Health[J]. Pediatr Clin North Am 54(2):237\\u0026ndash;237\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003ePacyna JM (2020) Recent advances in mercury research[J]. Sci Total Environ 738:139955\\u0026ndash;139958\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eGworek B, Dmuchowski W, Baczewska-Dąbrowska AH (2020) Mercury in the terrestrial environment: a review[J]. Environ Sci Europe 32(1):128\\u0026ndash;146\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eBudnik LT, Casteleyn L (2019) Mercury pollution in modern times and its socio-medical consequences[J]. Sci Total Environ 654:720\\u0026ndash;734\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eAjsuvakova OP, Tinkov AA, Aschner M et al (2020) Sulfhydryl groups as targets of mercury toxicity[J]. Coord Chem Rev 417:213343\\u0026ndash;213359\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eZhao Y, Zhou C, Guo X et al (2021) Exposed to Mercury-Induced Oxidative Stress, Changes of Intestinal Microflora, and Association between them in Mice[J]. Biol Trace Elem Res 199(5):1900\\u0026ndash;1907\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eHan B, Lv Z, Han X et al (2022) Harmful Effects of Inorganic Mercury Exposure on Kidney Cells: Mitochondrial Dynamics Disorder and Excessive Oxidative Stress[J]. Biol Trace Elem Res 200(4):1591\\u0026ndash;1597\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eHu XF, Lowe M, Chan HM (2021) Mercury exposure, cardiovascular disease, and mortality: A systematic review and dose-response meta-analysis[J]. Environ Res 193:110538\\u0026ndash;110572\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eRae (2022) Assessing Mercury Levels, Health Metrics, and Immune Function in Nonstranded Male California and Steller Sea Lions in Oregon[D]. Corvallis: Oregon State University, : 1\\u0026ndash;70\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eCariccio VL, Sam\\u0026agrave; A, Bramanti P et al (2019) Mercury Involvement in Neuronal Damage and in Neurodegenerative Diseases[J]. Biol Trace Elem Res 187(2):341\\u0026ndash;356\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eG\\u0026uuml;rkan R, Zengin HB (2023) Application of ultrasound assisted-cloud point extraction coupled with spectrophotometry for the selective extraction / pre-concentration of low levels of inorganic Hg (as Hg\\u003csub\\u003e2\\u003c/sub\\u003e\\u003csup\\u003e2+\\u003c/sup\\u003e /Hg\\u003csup\\u003e2+\\u003c/sup\\u003e) from liquid matrices[J]. Int J Environ Anal Chem, : 1\\u0026ndash;21\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eHong YS, Choi JY, Nho EY et al (2019) Determination of macro, micro and trace elements in citrus fruits by inductively coupled plasma-optical emission spectrometry (ICP-OES), ICP\\u0026ndash;mass spectrometry and direct mercury analyzer[J]. J Sci Food Agric 99(4):1870\\u0026ndash;1879\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eChen D, Lu L, Zhang H et al (2021) Sensitive Mercury Speciation Analysis in Water by High-Performance Liquid Chromatography-Atomic Fluorescence Spectrometry Coupling with Solid-Phase Extraction[J]. Anal Sci 37(9):1235\\u0026ndash;1240\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eVacchina V, Epova EN, B\\u0026eacute;rail S et al (2020) Tin and mercury and their speciation (organotin compounds and methylmercury) in worldwide red wine samples determined by ICP-MS and GC-ICP-MS[J]. Food Addit Contaminants: Part B 13(2):88\\u0026ndash;98\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eAlcay Y, Ozdemir E, Yildirim MS et al (2023) A methionine biomolecule-modified chromenylium-cyanine fluorescent probe for the analysis of Hg\\u003csup\\u003e2+\\u003c/sup\\u003e in the environment and living cells[J]. Talanta 259:124471\\u0026ndash;124480\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eYu Y, Liu C, Tian B et al (2020) A novel highly selective ratiometric fluorescent probe with large emission shift for detecting mercury ions in living cells and zebrafish[J]. Dyes Pigm 177:108290\\u0026ndash;108296\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eLiu S, Feng D, Zhang L et al (2020) A reaction-based ratiometric fluorescent probe for mercury ion detection in aqueous solution[J]. Spectrochim Acta Part A Mol Biomol Spectrosc 243:118817\\u0026ndash;118822\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eTang J, Wu H, Yin S et al (2019) An ESIPT-based fluorescent probe for Hg\\u003csup\\u003e2+\\u003c/sup\\u003e in aqueous solution and its application in live-cell imaging[J]. Tetrahedron Lett 60(7):541\\u0026ndash;546\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eLi H, Li J, Pan Z et al (2023) Highly selective and sensitive detection of Hg\\u003csup\\u003e2+\\u003c/sup\\u003e by a novel fluorescent probe with dual recognition sites[J]. Spectrochim Acta Part A Mol Biomol Spectrosc 291:122379\\u0026ndash;122392\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eChen H, Li X, Gao P et al (2022) A BODIPY-based turn-off fluorescent probe for mercury ion detection in solution and on test strips[J]. J Mol Struct 1262:133015\\u0026ndash;133020\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eChristopher Leslee DB, Karuppannan S, Kothottil MM (2021) Carbazole-hydrazinobenzothiazole a selective turn-on fluorescent sensor for Hg\\u003csup\\u003e2+\\u003c/sup\\u003eions - Its protein binding and electrochemical application studies[J]. J Photochem Photobiol A 415:113303\\u0026ndash;113311\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eMeng X, Wang J, Li X et al (2021) A large Stokes shift probe based enhanced ICT strategy for Hg\\u003csup\\u003e2+\\u003c/sup\\u003e-detection in cancer cells and zebrafish[J]. Microchem J 169:106551\\u0026ndash;106557\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eMohammad H, Saleh Musha Islam A, Sasmal M et al (2022) A fluorescein-2-(Pyridin-2-ylmethoxy) benzaldehyde conjugate for fluorogenic turn-ON recognition of Hg\\u003csup\\u003e2+\\u003c/sup\\u003e in water and living cells with logic gate and memory device applications[J]. Inorg Chim Acta 543:121165\\u0026ndash;121171\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eLafzi F, Saleh Hussein A, Kilic H et al (2023) The thioacetal-modified phenothiazine as a novel colorimetric and fluorescent chemosensor for mercury in aqueous media[J]. J Photochem Photobiol A 444:114958\\u0026ndash;114967\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003ePan Y, Guo Y, Li Y et al (2023) A new aggregation-induced emission-based fluorescent probe for effective detection of Hg\\u003csup\\u003e2+\\u003c/sup\\u003e and its multiple applications[J]. Chin Chem Lett 34(12):108237\\u0026ndash;108243\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eZhang C-X, Xiang M-H, Liu X-J et al (2019) Development of large Stokes shift, near-infrared fluorescence probe for rapid and bioorthogonal imaging of nitroxyl (HNO) in living cells[J]. Talanta 193:152\\u0026ndash;160\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eGrzelakowska A, Kolińska J, Zakłos-Szyda M et al (2020) Novel fluorescent probes for L-cysteine based on the xanthone skeleton[J]. J Photochem Photobiol A 387:112153\\u0026ndash;112163\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eHu Q, Zhang H, Ye P et al (2023) Xanthene-based polarity-sensitive fluorescent probe with large Stokes shifts for simultaneous two-color visualizing of lipid droplets and lysosomes[J]. Dyes Pigm 208:110874\\u0026ndash;110879\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eYouguo Qi et al (2022) A novel fluorescent probe with large Stokes shift for the detection of Ag\\u003csup\\u003e+\\u003c/sup\\u003e and Hg\\u003csup\\u003e2+\\u003c/sup\\u003e[J]. Opt Mater 123:111929\\u0026ndash;111935\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eStatements \\u0026amp; Declarations\\u003c/span\\u003e\\u003c/li\\u003e\\u003c/ol\\u003e\"},{\"header\":\"Scheme 1\",\"content\":\"\\u003cp\\u003eScheme 1 is available in the Supplementary Files section\\u003c/p\\u003e\"}],\"fulltextSource\":\"\",\"fullText\":\"\",\"funders\":[],\"hasAdminPriorityOnWorkflow\":false,\"hasManuscriptDocX\":true,\"hasOptedInToPreprint\":true,\"hasPassedJournalQc\":\"\",\"hasAnyPriority\":false,\"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\":\"info@researchsquare.com\",\"identity\":\"journal-of-fluorescence\",\"isNatureJournal\":false,\"hasQc\":true,\"allowDirectSubmit\":false,\"externalIdentity\":\"jofl\",\"sideBox\":\"Learn more about [Journal of Fluorescence](https://www.springer.com/journal/10895)\",\"snPcode\":\"10895\",\"submissionUrl\":\"https://submission.nature.com/new-submission/10895/3\",\"title\":\"Journal of Fluorescence\",\"twitterHandle\":\"\",\"acdcEnabled\":true,\"dfaEnabled\":true,\"editorialSystem\":\"em\",\"reportingPortfolio\":\"Springer Hybrid\",\"inReviewEnabled\":true,\"inReviewRevisionsEnabled\":false},\"keywords\":\"xanthene, Hg2+, food samples, cell imaging\",\"lastPublishedDoi\":\"10.21203/rs.3.rs-4019763/v1\",\"lastPublishedDoiUrl\":\"https://doi.org/10.21203/rs.3.rs-4019763/v1\",\"license\":{\"name\":\"CC BY 4.0\",\"url\":\"https://creativecommons.org/licenses/by/4.0/\"},\"manuscriptAbstract\":\"\\u003cp\\u003eThe mercury-loving unit aminothiourea was introduced into the xanthene fluorophore to synthesized the probe molecule \\u003cb\\u003eNXH\\u003c/b\\u003e. \\u003cb\\u003eNXH\\u003c/b\\u003e has a specific response to Hg\\u003csup\\u003e2+\\u003c/sup\\u003e, and with the addition of (0\\u0026thinsp;~\\u0026thinsp;50 \\u0026micro;M) Hg\\u003csup\\u003e2+\\u003c/sup\\u003e, the fluorescence intensity of the probe solution was quenched from 2352 a.u. to about 308 a.u.. The probe \\u003cb\\u003eNXH\\u003c/b\\u003e exhibited excellent detection performance of high sensitivity (LOD\\u0026thinsp;=\\u0026thinsp;96.3 nM), real-time response (105 s), wide pH range (2.1\\u0026thinsp;~\\u0026thinsp;9.3), and strong anti-interference ability for Hg\\u003csup\\u003e2+\\u003c/sup\\u003e. At the same time, the probe \\u003cb\\u003eNXH\\u003c/b\\u003e has wide range of applications for Hg\\u003csup\\u003e2+\\u003c/sup\\u003e detection, which can be used to create molecular logic gates, make Hg\\u003csup\\u003e2+\\u003c/sup\\u003e detection test paper, as well as the fluorescence imaging of Hg\\u003csup\\u003e2+\\u003c/sup\\u003e in Hela live cells and tea samples.\\u003c/p\\u003e\",\"manuscriptTitle\":\"A fluorescent probe for Hg 2+ specific recognition based on xanthene and its application in food detection and cell imaging\",\"msid\":\"\",\"msnumber\":\"\",\"nonDraftVersions\":[{\"code\":1,\"date\":\"2024-03-11 19:01:47\",\"doi\":\"10.21203/rs.3.rs-4019763/v1\",\"editorialEvents\":[{\"type\":\"communityComments\",\"content\":0},{\"type\":\"decision\",\"content\":\"Revision requested\",\"date\":\"2024-03-24T17:01:34+00:00\",\"index\":\"\",\"fulltext\":\"\"},{\"type\":\"editorInvitedReview\",\"content\":\"\",\"date\":\"2024-03-23T07:18:59+00:00\",\"index\":\"hide\",\"fulltext\":\"\"},{\"type\":\"reviewerAgreed\",\"content\":\"88df53a8-30d8-43fc-8538-5b5b4d0d6203\",\"date\":\"2024-03-14T12:12:50+00:00\",\"index\":\"hide\",\"fulltext\":\"\"},{\"type\":\"reviewersInvited\",\"content\":\"\",\"date\":\"2024-03-12T11:16:30+00:00\",\"index\":\"\",\"fulltext\":\"\"},{\"type\":\"checksComplete\",\"content\":\"\",\"date\":\"2024-03-07T04:28:51+00:00\",\"index\":\"\",\"fulltext\":\"\"},{\"type\":\"editorAssigned\",\"content\":\"\",\"date\":\"2024-03-07T04:28:51+00:00\",\"index\":\"\",\"fulltext\":\"\"},{\"type\":\"submitted\",\"content\":\"Journal of Fluorescence\",\"date\":\"2024-03-06T07:18:34+00:00\",\"index\":\"\",\"fulltext\":\"\"}],\"status\":\"published\",\"journal\":{\"display\":true,\"email\":\"info@researchsquare.com\",\"identity\":\"journal-of-fluorescence\",\"isNatureJournal\":false,\"hasQc\":true,\"allowDirectSubmit\":false,\"externalIdentity\":\"jofl\",\"sideBox\":\"Learn more about [Journal of Fluorescence](https://www.springer.com/journal/10895)\",\"snPcode\":\"10895\",\"submissionUrl\":\"https://submission.nature.com/new-submission/10895/3\",\"title\":\"Journal of Fluorescence\",\"twitterHandle\":\"\",\"acdcEnabled\":true,\"dfaEnabled\":true,\"editorialSystem\":\"em\",\"reportingPortfolio\":\"Springer Hybrid\",\"inReviewEnabled\":true,\"inReviewRevisionsEnabled\":false}}],\"origin\":\"\",\"ownerIdentity\":\"5ba650cf-9e30-4a63-b465-b2322ac1139e\",\"owner\":[],\"postedDate\":\"March 11th, 2024\",\"published\":true,\"recentEditorialEvents\":[],\"rejectedJournal\":[],\"revision\":\"\",\"amendment\":\"\",\"status\":\"under-review\",\"subjectAreas\":[],\"tags\":[],\"updatedAt\":\"2024-04-05T16:42:29+00:00\",\"versionOfRecord\":[],\"versionCreatedAt\":\"2024-03-11 19:01:47\",\"video\":\"\",\"vorDoi\":\"\",\"vorDoiUrl\":\"\",\"workflowStages\":[]},\"version\":\"v1\",\"identity\":\"rs-4019763\",\"journalConfig\":\"researchsquare\"},\"__N_SSP\":true},\"page\":\"/article/[identity]/[[...version]]\",\"query\":{\"redirect\":\"/article/rs-4019763\",\"identity\":\"rs-4019763\",\"version\":[\"v1\"]},\"buildId\":\"qtupq5eGEP_6zYnWcrvyt\",\"isFallback\":false,\"isExperimentalCompile\":false,\"dynamicIds\":[84888],\"gssp\":true,\"scriptLoader\":[]}","source_license":"CC-BY-4.0","license_restricted":false}