Preparation methods of bimetallic selenides and their non-enzymatic electrochemical sensors and applications

Abstract

This invention relates to the field of pollutant detection technology, and discloses a method for preparing bimetallic selenides and its non-enzymatic electrochemical sensor and applications. The reference electrode of the non-enzymatic electrochemical sensor is a silver / silver chloride electrode, the auxiliary electrode is a platinum wire electrode, and the working electrode is a glassy carbon composite electrode containing a bimetallic selenide coating. The bimetallic selenide is CuInSe2, which exhibits sensitivity in identifying parathion. This improves the accuracy and ease of operation in detecting parathion and reduces the detection cost. The method for preparing the bimetallic selenide proposed in this invention uses ethylamine and N,N-dimethylformamide as solvents, and through a solvothermal reaction, reacts cuprous chloride, indium chloride, and selenium powder to generate CuInSe2, which has the advantages of high reaction efficiency and low manufacturing cost.

Description

Technical Field

[0001] This invention relates to the field of pollutant detection technology, and in particular to a method for preparing bimetallic selenides and their non-enzymatic electrochemical sensors and applications. Background Technology

[0002] Organophosphorus pesticides are widely used as highly effective insecticides, fungicides, herbicides, and plant growth regulators in the control of crop diseases and pests and in increasing grain yields.

[0003] The insecticidal active ingredient in organophosphorus pesticides is parathion. Parathion is highly toxic and can enter the human body through the digestive tract, skin, mucous membranes, and respiratory tract. It can inhibit the activity of acetylcholinesterase in the human body, affect the function of the nervous system in the brain, cause respiratory disorders, and even lead to death.

[0004] In the prior art, the methods for detecting organophosphorus pesticide residues for detecting parathion content include chromatographic detection methods, enzyme inhibition detection methods, and immunoassay methods.

[0005] Chromatographic detection methods are divided into high performance liquid chromatography, gas chromatography, and chromatography-mass spectrometry. These chromatographic detection methods have drawbacks such as high equipment requirements, expensive equipment, complicated sample processing, and long detection cycles. In addition, they require professional personnel to operate and maintain them, resulting in insufficient convenience of detection operations.

[0006] Enzyme inhibition detection methods are divided into rapid test card methods and spectrophotometric methods. These enzyme inhibition detection methods are susceptible to interference from the external environment and are prone to producing false positive results.

[0007] Immunological detection methods are divided into enzyme-linked immunosorbent assay (ELISA), fluorescence immunoassay (FIA), and chemiluminescence immunoassay (CIA). These immunological detection methods require the use of colloidal gold, and the detection costs are high. Summary of the Invention

[0008] To address the aforementioned problems, the primary objective of this invention is to propose a non-enzymatic electrochemical sensor to solve the issues of insufficient detection accuracy, low operational convenience, and high detection costs for sulfur and phosphorus.

[0009] Furthermore, a second objective of this invention is to provide a method for preparing bimetallic selenides to obtain CuInSe2 with low manufacturing costs.

[0010] Furthermore, a third objective of this invention is to provide a method for using a bimetallic selenide, CuInSe2, to obtain a non-enzymatic electrochemical sensor with good operational convenience and detection sensitivity.

[0011] To achieve the above objectives, the present invention adopts the following technical solution:

[0012] A non-enzymatic electrochemical sensor using a bimetallic selenide includes a working electrode, an auxiliary electrode, and a reference electrode;

[0013] The reference electrode is a silver / silver chloride electrode, the auxiliary electrode is a platinum wire electrode, and the working electrode is a glassy carbon composite electrode with a bimetallic selenide coating.

[0014] The bimetallic selenide is CuInSe2, and the CuInSe2 contained therein has specific sensitivity to sulfur and phosphorus. The diameter of the glassy carbon composite electrode is 5 mm, and the content of CuInSe2 in the coating is 0.08-0.15 mg.

[0015] Furthermore, this invention proposes a method for preparing a bimetallic selenide, wherein the prepared bimetallic selenide is used in the preparation of the aforementioned non-enzymatic electrochemical sensor using the bimetallic selenide, comprising the following steps:

[0016] S1) Place the N,N-dimethylformamide solution under an inert gas protection environment, and add cuprous chloride and indium chloride respectively while stirring to prepare the first solution;

[0017] S2) Place the N,N-dimethylformamide solution under an inert gas protection environment, and add selenium powder and ethylamine separately while stirring to obtain a second solution;

[0018] S3) Under the protection of inert gas and magnetic stirring, the first solution and the second solution are added to the reaction vessel respectively and mixed evenly to obtain the reaction solution;

[0019] S4) The reaction solution is slowly heated to the reaction temperature and kept at that temperature until the reaction stops. Then it is naturally cooled to room temperature, washed three times with anhydrous ethanol, and dried to obtain the bimetallic selenide with a hexagonal structure.

[0020] Preferably, the temperature of the N,N-dimethylformamide solution in steps S1) and S2) is 120°C.

[0021] Preferably, the molar concentration ratio of cuprous chloride, indium chloride and selenium powder is 1:1:1.

[0022] Preferably, in step S2), the molar concentration of selenium powder to the volume ratio of ethylamine is 1 mmol: 1 mL.

[0023] Add an appropriate amount of ethylamine as a solvent to dissolve the selenium powder.

[0024] Preferably, in step S4), the reaction temperature is 220-260℃.

[0025] Preferably, in step S4), the drying temperature is 60°C and the drying time is 24 hours.

[0026] Preferably, the inert protective gas is nitrogen or helium.

[0027] Furthermore, the present invention also proposes an application of bimetallic selenide, wherein the bimetallic selenide prepared by the above-described method is configured into a dispersion and coated onto a glassy carbon composite electrode, and the glassy carbon composite electrode is used as the working electrode of a non-enzymatic electrochemical sensor to detect parathion in organic pesticides.

[0028] The beneficial effects of the technical solution of the present invention are as follows: the non-enzymatic electrochemical sensor using bimetallic selenide uses a glassy carbon composite electrode coated with CuInSe2 as the working electrode, which has good sensitivity for identifying parathion, can improve the accuracy and ease of operation of parathion detection, and reduce the detection cost of parathion.

[0029] Furthermore, the present invention proposes a method for preparing bimetallic selenides, using ethylamine and N,N-dimethylformamide as solvents, and through a solvothermal reaction, chelating cuprous chloride, indium chloride, and selenium powder in the reaction solution to generate CuInSe2, which has the advantages of high reaction efficiency and low manufacturing cost.

[0030] Furthermore, the present invention proposes an application of a bimetallic selenide, in which the prepared CuInSe2 bimetallic selenide is applied to the working electrode of a non-enzymatic electrochemical sensor. This can reduce the cost of detecting parathion in the non-enzymatic electrochemical sensor and improve the accuracy and ease of operation of the non-enzymatic electrochemical sensor for detecting parathion. Attached Figure Description

[0031] Figure 1 This is a SEM image of CuInSe2 obtained in Example 1 of the present invention;

[0032] Figure 2 The X-ray diffraction pattern of the bimetallic selenide CuInSe2 obtained in Example 1 of the present invention;

[0033] Figure 3 These are square wave voltammetry curves of the non-enzymatic electrochemical sensor used in Examples 1, 1, and 2 of the present invention to detect parathion.

[0034] Figure 4 Square wave voltammetry curves of different concentrations of parathion detected by the non-enzymatic electrochemical sensor of Example 1 of the present invention;

[0035] Figure 5 The non-enzymatic electrochemical sensor of Example 1 of the present invention shows the linear relationship between the peak value of the square wave voltammetric current and the concentration of parathion at different concentrations. Detailed Implementation

[0036] The technical solution of the present invention will be further illustrated below through specific embodiments.

[0037] In the description of this specification, references to terms such as "embodiment," "example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0038] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

[0039] A non-enzymatic electrochemical sensor using a bimetallic selenide includes a working electrode, an auxiliary electrode, and a reference electrode;

[0040] The reference electrode is a silver / silver chloride electrode, the auxiliary electrode is a platinum wire electrode, and the working electrode is a glassy carbon composite electrode with a bimetallic selenide coating.

[0041] The bimetallic selenide is CuInSe2, and the CuInSe2 contained therein has a high sensitivity to sulfur and phosphorus.

[0042] Figure 1 The image shown is a scanning electron microscope (SEM) image of CuInSe2, a bimetallic selenide. The molecule of CuInSe2 has a hexagonal structure and exhibits sensitivity in recognizing parathion. A glassy carbon composite electrode with a CuInSe2 coating is formed by coating a glassy carbon electrode and used as the working electrode of a non-enzymatic electrochemical sensor. This can improve the sensitivity of the non-enzymatic electrochemical sensor in recognizing parathion, thereby improving the accuracy and ease of operation of parathion detection and reducing the detection cost of parathion.

[0043] Specifically, the glassy carbon composite electrode has a diameter of 5 mm, and the CuInSe2 content in the coating is 0.08-0.15 mg.

[0044] The glassy carbon composite electrode can be prepared by using 0.08-0.15 mg of CuInSe2 to make a dispersion and coating it onto a glassy carbon electrode, which has low manufacturing cost.

[0045] Furthermore, this invention proposes a method for preparing a bimetallic selenide, wherein the prepared bimetallic selenide is used in the preparation of the aforementioned non-enzymatic electrochemical sensor using the bimetallic selenide, comprising the following steps:

[0046] S1) Place the N,N-dimethylformamide solution under an inert gas protection environment, and add cuprous chloride and indium chloride respectively while stirring to prepare the first solution;

[0047] S2) Place the N,N-dimethylformamide solution under an inert gas protection environment, and add selenium powder and ethylamine separately while stirring to obtain a second solution;

[0048] S3) Under the protection of inert gas and magnetic stirring, the first solution and the second solution are added to the reaction vessel respectively and mixed evenly to obtain the reaction solution;

[0049] S4) The reaction solution is slowly heated to the reaction temperature and kept at that temperature until the reaction stops. Then it is naturally cooled to room temperature, washed three times with anhydrous ethanol, and dried to obtain the bimetallic selenide with a hexagonal structure.

[0050] The method for preparing the bimetallic selenide of the present invention uses N,N-dimethylformamide solution and ethylamine as solvents, and generates CuInSe2 from cuprous chloride, indium chloride and selenium powder through a solvothermal reaction, which has the advantages of high reaction efficiency and low manufacturing cost.

[0051] Preferably, the temperature of the N,N-dimethylformamide solution in steps S1) and S2) is 120°C.

[0052] Heating the N,N-dimethylformamide solution to 120°C can remove oxygen from the N,N-dimethylformamide solution, thus preventing the added cuprous chloride from being oxidized.

[0053] Preferably, the molar concentration ratio of cuprous chloride, indium chloride and selenium powder is 1:1:1.

[0054] Adding cuprous chloride, indium chloride, and selenium powder in a molar ratio of 1:1:1 can avoid material waste and reduce the formation of reaction byproducts.

[0055] Preferably, in step S2), the molar concentration of selenium powder to the volume ratio of ethylamine is 1 mmol: 1 mL.

[0056] Adding an appropriate amount of ethylamine as a solvent to dissolve selenium powder can improve the reaction efficiency of the solvothermal reaction.

[0057] Preferably, in step S4), the reaction temperature is 220-260℃.

[0058] A reaction temperature of 220-260℃ is beneficial for increasing the reaction rate of a solvothermal reaction.

[0059] Preferably, in step S4), the drying temperature is 60°C and the drying time is 24 hours.

[0060] Drying at 60℃ for 24 hours can completely remove residual anhydrous ethanol from the prepared bimetallic selenide.

[0061] Preferably, the inert protective gas is nitrogen or helium.

[0062] Using nitrogen as the inert protective gas is preferred, as it offers better manufacturing costs.

[0063] Furthermore, the present invention also proposes an application of bimetallic selenide, wherein the bimetallic selenide prepared by the above-described method is configured into a dispersion and coated onto a glassy carbon composite electrode, and the glassy carbon composite electrode is used as the working electrode of a non-enzymatic electrochemical sensor to detect parathion in organic pesticides.

[0064] By applying the prepared bimetallic selenide CuInSe2 to the working electrode of a non-enzymatic electrochemical sensor, the cost of detecting parathion can be reduced, and the accuracy and ease of operation of the non-enzymatic electrochemical sensor for detecting parathion can be improved.

[0065] Example 1 and Comparative Examples 1-2

[0066] 1. Prepare the bimetallic selenide of Example 1 according to the following steps:

[0067] S1) Place 5 mL of N,N-dimethylformamide solution at 120℃ under nitrogen protection, and while stirring, add 0.5 mmol of cuprous chloride and 0.5 mmol of indium chloride to obtain the first solution;

[0068] S2) Place 5 mL of N,N-dimethylformamide solution at 120 °C under nitrogen protection, and while stirring, add 0.5 mmol of selenium powder and 0.5 mL of ethylamine to obtain the second solution;

[0069] S3) Under nitrogen protection and magnetic stirring conditions, the first solution and the second solution are added to the reaction vessel respectively and mixed evenly to obtain the reaction solution;

[0070] S4) The reaction solution was slowly heated to 250°C and kept at that temperature until the reaction stopped. Then it was naturally cooled to room temperature, washed three times with anhydrous ethanol, and dried at 60°C for 24 hours to obtain the bimetallic selenide CuInSe2 with a hexagonal structure of Example 1.

[0071] The SEM image of the prepared bimetallic selenide CuInSe2 is shown below. Figure 1 As shown, the X-ray diffraction pattern is as follows: Figure 2 shown.

[0072] 2. Preparation of metal selenides of Comparative Example 1 and Comparative Example 2

[0073] 2.1 Prepare the metal selenide of Comparative Example 1 according to the following steps:

[0074] S1) Place 5 mL of N,N-dimethylformamide solution at 120℃ under nitrogen protection, and add 0.5 mmol of cuprous chloride while stirring to prepare the first solution;

[0075] S2) Place 5 mL of N,N-dimethylformamide solution at 120 °C under nitrogen protection, and while stirring, add 0.5 mmol of selenium powder and 0.5 mL of ethylamine to obtain the second solution;

[0076] S3) Under nitrogen protection and magnetic stirring conditions, the first solution and the second solution are added to the reaction vessel respectively and mixed evenly to obtain the reaction solution;

[0077] S4) The reaction solution was slowly heated to 250°C and kept at that temperature until the reaction stopped. Then it was naturally cooled to room temperature, washed three times with anhydrous ethanol, and dried at 60°C for 24 hours to obtain the metal selenide Cu2Se of Comparative Example 1.

[0078] 2.2 Prepare the metal selenide of Comparative Example 2 according to the following steps:

[0079] S1) Place 5 mL of N,N-dimethylformamide solution at 120 °C under nitrogen protection, and add 0.5 mmol of indium chloride while stirring to prepare the first solution;

[0080] S2) Place 5 mL of N,N-dimethylformamide solution at 120 °C under nitrogen protection, and while stirring, add 0.5 mmol of selenium powder and 0.5 mL of ethylamine to obtain the second solution;

[0081] S3) Under nitrogen protection and magnetic stirring conditions, the first solution and the second solution are added to the reaction vessel respectively and mixed evenly to obtain the reaction solution;

[0082] S4) The reaction solution was slowly heated to 250°C and kept at that temperature until the reaction stopped. Then it was naturally cooled to room temperature, washed three times with anhydrous ethanol, and dried at 60°C for 24 hours to obtain the metal selenide indium selenide In2Se3 of Comparative Example 2.

[0083] 3. Preparation of non-enzymatic electrochemical sensors in Examples 1, 1 (Comparative Example), and 2 (Comparative Example)

[0084] 3.1 Take three mixed solutions prepared by 300 μL of anhydrous ethanol, 600 μL of distilled water and 100 μL of 5% Nafion solution respectively, and add 10 mg of the bimetallic selenide CuInSe2 prepared in Example 1, the metal selenide Cu2Se prepared in Comparative Example 1 and the metal selenide In2Se3 prepared in Comparative Example 2 respectively. Then, disperse them by ultrasonication at 180 W for 2 h to obtain the dispersions of Example 1, Comparative Example 1 and Comparative Example 2 respectively.

[0085] 3.2 Using a 10 μL Eppendorf pipette, 10 μL of the dispersions of Example 1, Comparative Example 1, and Comparative Example 2 were respectively transferred and dropped onto the clean surfaces of three glassy carbon electrodes with a diameter of 5 mm, which were polished with 0.05 μm Al2O3 powder and ultrasonically cleaned. The electrodes were then air-dried for 24 h to obtain the glassy carbon composite electrodes of Example 1, Comparative Example 1, and Comparative Example 2.

[0086] 3.3 Using a platinum wire electrode as an auxiliary electrode, a silver / silver chloride electrode as a reference electrode, and the glassy carbon composite electrode of Example 1, Comparative Example 1, and Comparative Example 2 as the working electrode, non-enzymatic electrochemical sensors of Example 1, Comparative Example 1, and Comparative Example 2 were prepared.

[0087] 4. Comparison of the detection sensitivity of the non-enzymatic electrochemical sensors in Example 1, Comparative Example 1, and Comparative Example 2

[0088] 4.1 Prepare a 0.1 mol / L phosphate buffer solution with a pH of 8.0 and a parathion concentration of 10 μM to obtain the comparison and detection solution;

[0089] 4.2 The working electrodes of the non-enzymatic electrochemical sensors of Example 1, Comparative Example 1, and Comparative Example 2 were placed in the comparison detection solution and immersed for 240 s at an electrode potential of -0.5 V. The response currents of the non-enzymatic electrochemical sensors of Example 1, Comparative Example 1, and Comparative Example 2 to parathion in the comparison detection solution were recorded using the square wave voltammetry method, and the corresponding standard curves were plotted. The results are as follows: Figure 3 shown.

[0090] from Figure 3 It can be seen that the peak current value of the standard curve of Example 1 is significantly higher than that of the standard curves of Comparative Example 1 and Comparative Example 2, indicating that the bimetallic selenide CuInSe2 / glassy carbon composite electrode has better sensitivity for sulfur and phosphorus detection.

[0091] 5. Detection of different concentrations of parathion using the non-enzymatic electrochemical sensor of Example 1.

[0092] 5.1 Prepare seven detection solutions by using 0.1 mol / L phosphate buffer solutions with a pH of 8.0 and containing parathion concentrations of 0.5 μM, 1 μM, 5 μM, 10 μM, 50 μM, 100 μM, and 200 μM, respectively.

[0093] 5.2 After immersion at an electrode potential of -0.5V for 240s, the working electrode of the non-enzymatic electrochemical sensor from Example 1 was placed in seven detection solutions. The response currents of the corresponding parathion detection solutions were recorded using the square wave voltammetry method, and the corresponding standard curves were plotted. The results are as follows: Figure 4 shown.

[0094] 5.3 Based on the values ​​of parathion concentration and corresponding peak current detected in Example 1 above, the obtained linear regression equation is: y = 8.765(±0.850)x + 9.341(±2.227), R 2 =0.9461, where y is the current value and x is the logarithm of the parathion concentration value, such as Figure 5 As shown, the detection limit of the non-enzymatic electrochemical sensor in Example 1 is 0.3439 μM.

[0095] Depend on Figure 4 As can be seen, each standard curve has a distinct peak current value, and the corresponding peak current value increases significantly with the increase of parathion concentration. Based on the linear relationship between parathion concentration and corresponding peak current value detected in Example 1, the detection limit of the non-enzymatic electrochemical sensor in Example 1 is calculated to be 0.3439 μM, indicating that the bimetallic selenide CuInSe2 / glassy carbon composite electrode has good detection sensitivity for parathion.

[0096] 6. Detection of actual samples using the non-enzymatic electrochemical sensor from Example 1:

[0097] Parathion was extracted from apple samples using acetonitrile. The sample solution was prepared with 0.1 mol / L phosphate buffer to a pH of 8.0. The working electrode of the non-enzymatic electrochemical sensor from Example 1 was placed in the sample solution and immersed for 240 s at a potential of -0.5 V. The response current of parathion in the sample solution was determined by square wave voltammetry. The recovery rate was 95.3%-104.5%, and the RSD was less than 3%.

[0098] In actual sample testing, the non-enzymatic electrochemical sensor prepared in Example 1 of the present invention has good detection accuracy, indicating that the non-enzymatic electrochemical sensor of the present invention can be used for the determination of parathion residues in agricultural products.

[0099] In summary, the non-enzymatic electrochemical sensor using bimetallic selenide described in this invention uses a glassy carbon composite electrode coated with CuInSe2 as the working electrode, which has good sensitivity for identifying parathion, improves the accuracy and ease of operation of parathion detection, and reduces the detection cost of parathion.

[0100] Furthermore, the present invention proposes a method for preparing bimetallic selenides, using ethylamine and N,N-dimethylformamide as solvents, and through a solvothermal reaction, to generate CuInSe2 from cuprous chloride, indium chloride and selenium powder, which has the advantages of high reaction efficiency and low manufacturing cost.

[0101] Furthermore, the present invention proposes an application of a bimetallic selenide, in which the prepared CuInSe2 bimetallic selenide is applied to the working electrode of a non-enzymatic electrochemical sensor. This can reduce the cost of detecting parathion in the non-enzymatic electrochemical sensor and improve the accuracy and ease of operation of the non-enzymatic electrochemical sensor for detecting parathion.

[0102] The technical principles of the present invention have been described above with reference to specific embodiments. These descriptions are merely for explaining the principles of the invention and should not be construed as limiting the scope of protection of the invention in any way. Based on this explanation, those skilled in the art can readily conceive of other specific embodiments of the invention without inventive effort, and these embodiments will all fall within the scope of protection of the present invention.

Claims

1. An application of a bimetallic selenide in a non-enzymatic electrochemical sensor, the non-enzymatic electrochemical sensor comprising a working electrode, an auxiliary electrode, and a reference electrode, characterized in that: The reference electrode is a silver / silver chloride electrode, the auxiliary electrode is a platinum wire electrode, and the working electrode is a glassy carbon composite electrode with a bimetallic selenide coating. The bimetallic selenide is CuInSe2, and the CuInSe2 contained therein has a high sensitivity to sulfur and phosphorus. The preparation of the bimetallic selenide includes the following steps: S1) Place the N,N-dimethylformamide solution under an inert gas protection environment, and add cuprous chloride and indium chloride separately while stirring to prepare the first solution; S2) Place the N,N-dimethylformamide solution under an inert gas protection environment, and add selenium powder and ethylamine separately while stirring to obtain a second solution; S3) Under the protection of inert gas and magnetic stirring, the first solution and the second solution are added to the reaction vessel respectively and mixed evenly to obtain the reaction solution; S4) Slowly heat the reaction solution to the reaction temperature, keep it at the temperature until the reaction stops, cool it naturally to room temperature, wash it three times with anhydrous ethanol, and dry it to obtain the bimetallic selenide with a hexagonal structure. The prepared bimetallic selenide was prepared into a dispersion and coated onto a glassy carbon composite electrode. The glassy carbon composite electrode was then used as the working electrode of a non-enzymatic electrochemical sensor to detect parathion in organic pesticides.

2. The application of the bimetallic selenide according to claim 1 in a non-enzymatic electrochemical sensor, characterized in that, The glassy carbon composite electrode has a diameter of 5 mm, and the CuInSe2 content in the coating is 0.08-0.15 mg.

3. The application of the bimetallic selenide according to claim 1 in a non-enzymatic electrochemical sensor, characterized in that, The temperature of the N,N-dimethylformamide solution in steps S1) and S2) is 120°C.

4. The application of the bimetallic selenide according to claim 1 in a non-enzymatic electrochemical sensor, characterized in that, The molar ratio of cuprous chloride, indium chloride, and selenium powder is 1:1:

1.

5. The application of the bimetallic selenide according to claim 1 in a non-enzymatic electrochemical sensor, characterized in that, In step S2), the molar concentration of selenium powder to the volume ratio of ethylamine is 1 mmol: 1 mL.

6. The application of the bimetallic selenide according to claim 1 in a non-enzymatic electrochemical sensor, characterized in that, In step S4), the reaction temperature is 220-260℃.

7. The application of the bimetallic selenide according to claim 1 in a non-enzymatic electrochemical sensor, characterized in that, In step S4), the drying temperature is 60℃ and the drying time is 24h.

8. The application of the bimetallic selenide according to claim 1 in a non-enzymatic electrochemical sensor, characterized in that, The inert protective gas is nitrogen or helium.

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