MXene MB / PtNPs electrochemical sensor, preparation method thereof and carbendazim detection method

Abstract

The invention relates to the technical field of electrochemical sensing, in particular to an MXene-coated MB / PtNPs electrochemical sensor and a preparation method thereof and a carbendazim detection method, MXene is used as a carrier, PtNPs is embedded between layers and on the surface of MXene through reduction reaction, then electroactive molecules MB are introduced through electrostatic interaction, an MXene-coated MB / PtNPs composite material is formed, and the MXene-coated MB / PtNPs electrochemical sensor is prepared. And then modifying a glassy carbon electrode by using the MXene coated MB / PtNPs composite material to prepare the MXene coated MB / PtNPs electrochemical sensor. The compound is used as a ratio electrochemical sensor for detecting carbendazim, the linear range of the compound to carbendazim is 10-30000 ng / mL, the detection limit is 3.3 ng / mL, the detection speed is high, the sensitivity is high, the linear range is wide, the precision is high, the detection limit is low, meanwhile, the anti-interference performance and repeatability are good, and the compound has potential application prospects in the field of agricultural product quality detection.

Description

Technical Field

[0001] The present invention relates to the field of electrochemical sensing technology, and in particular to a MXene@MB / PtNPs electrochemical sensor and a preparation method thereof, and a method for detecting carbendazim. Background Art

[0002] Carbendazim (CBZ) is a benzimidazole fungicide commonly used in crops to protect vegetables and fruits from a variety of fungi and pests. Although the use of pesticides has improved the quality of agricultural products, excessive pesticide residues have harmed human health and caused long-term adverse effects on the environment. Therefore, it is of great significance to establish a sensitive and reliable determination method.

[0003] There are many detection technologies for CBZ, including high performance liquid chromatography (HPLC), ultraviolet spectrophotometry (UV), infrared spectroscopy and fluorescence. However, these detection technologies have the disadvantages of expensive instruments, long time consumption and complicated operation. It is necessary to develop a simple, fast and efficient detection method.

[0004] Compared with the above methods, the electrochemical method has great advantages in terms of simple instrumentation, convenient operation, low cost, and fast response speed. At present, electrochemical sensors for single pesticides have good sensitivity and selectivity, but their detection accuracy needs to be further improved. The ratio electrochemical sensor based on the ratio strategy has a dual response signal for the target, and quantifies the concentration of the target by measuring the ratio of the dual signals, which can effectively improve the accuracy of the electrochemical sensor. Therefore, it is of great research significance to develop a ratio electrochemical sensor that can achieve high-sensitivity and high-precision detection of CBZ. Summary of the invention

[0005] In order to solve the above technical problems, a MXene@MB / PtNPs electrochemical sensor and a preparation method thereof, and a method for detecting carbendazim are provided. The present invention constructs a ratio electrochemical sensor by modifying a MXene@methylene blue / platinum nanoparticle (MXene@MB / PtNPs) composite material on a glassy carbon electrode to achieve high-sensitivity ratio detection of carbendazim, which has the advantages of fast speed, high sensitivity, high accuracy, etc.

[0006] In order to achieve the above objectives, the present invention is implemented by the following technical solutions:

[0007] The first aspect of the present invention provides a method for preparing a MXene@MB / PtNPs electrochemical sensor, comprising the following steps:

[0008] S1. Surface polishing and cleaning of glassy carbon electrode (GCE);

[0009] S2. Preparation of MXene@MB / PtNPs composite materials:

[0010] ① Add H2PtCl6 solution to the aqueous dispersion of MXene, and after uniform dispersion, add formic acid, stir and react at room temperature, and obtain MXene / PtNPs material after solid-liquid separation, washing and drying;

[0011] ② Forming a water dispersion of MXene / PtNPs material, adding methylene blue, stirring the reaction at room temperature, and obtaining a MXene@MB / PtNPs composite material after solid-liquid separation, washing, and drying;

[0012] S3. Dispersing the MXene@MB / PtNPs composite material in water to form a MXene@MB / PtNPs solution, coating the solution on the surface of the glassy carbon electrode, and drying at room temperature to obtain a MXene@MB / PtNPs electrochemical sensor.

[0013] Furthermore, the concentration of the MXene@MB / PtNPs solution is 0.05-5 mg / mL, preferably 0.5-1 mg / mL; 4-8 μL of the MXene@MB / PtNPs solution is dripped onto the glassy carbon electrode.

[0014] Furthermore, ultrasonic treatment is used to form a corresponding aqueous dispersion, and the ultrasonic treatment time is 10-40 minutes; the aqueous dispersion of MXene, the H2PtCl6 solution and the formic acid are stirred and reacted at room temperature for 14-20 hours; the aqueous dispersion of MXene / PtNPs material and the methylene blue are stirred and reacted at room temperature for 1-4 hours.

[0015] Furthermore, the volume ratio of the MXene water dispersion, the H2PtCl6 solution, and the formic acid is 5-50mL:40-160μL:0.2-2mL; the mass ratio of the MXene / PtNPs material to the methylene blue is 10-100:0.1-10.

[0016] Furthermore, the ratio of MXene to water in the aqueous dispersion of MXene is 15-150 mg: 5-50 mL; the concentration of the H2PtCl6 solution is in the range of 8-13 mM; and the ratio of MXene / PtNPs material to water in the MXene@MB / PtNPs solution is 10-100 mg: 5-50 mL.

[0017] Furthermore, the diameter of the glassy carbon electrode is 3 mm; the glassy carbon electrode is polished with aluminum oxide powder, and the particle size of the aluminum oxide powder is 0.3 μm and 0.05 μm.

[0018] The second aspect of the present invention provides a MXene@MB / PtNPs electrochemical sensor prepared by the above preparation method.

[0019] The last aspect of the present invention provides a method for detecting carbendazim, comprising the following steps:

[0020] (1) preparing a series of carbendazim standard solutions with different concentrations, and placing a plurality of MXene@MB / PtNPs electrochemical sensors, reference electrodes, and counter electrodes prepared by the above preparation method in the carbendazim standard solutions at the same time, wherein one concentration of the carbendazim standard solution corresponds to one MXene@MB / PtNPs electrochemical sensor;

[0021] In a three-electrode system, the MXene@MB / PtNPs electrochemical sensor was used as the working electrode, the Ag / AgCl electrode was used as the reference electrode, and the platinum wire was used as the counter electrode. The differential pulse voltammetry (DPV) method was used to detect the carbendazim standard solution corresponding to a series of concentrations, and the peak currents were I MB and peak current I CBZ ;

[0022] (2) A series of concentrations of the carbendazim standard solution are used as the horizontal axis, denoted as C CBZ , with a peak current I CBZ With the peak current I MB The ratio is the ordinate, denoted as I CBZ / I MB , draw the standard curve, and obtain the standard curve equation after linear fitting;

[0023] (3) The MXene@MB / PtNPs electrochemical sensor prepared by the above preparation method is placed in the test solution, and detection is performed using differential pulse voltammetry (DPV) in a three-electrode system according to the method of step (1), the measured results are recorded, and substituted into the standard curve equation to obtain the concentration of carbendazim in the test solution.

[0024] Furthermore, a series of carbendazim standard solutions were prepared in the concentration range of 1×10 -8 ~3×10 -5 g / mL; when testing the test solution, adjusting the pH value of the test solution to 5.5-6.5;

[0025] The standard curve equation is: CBZ / I MB =0.071+0.376×C CBZ , R 2=0.994, the linear range is 10 ng / mL to 30 μg / mL, and the detection limit concentration of the MXene@MB / PtNPs electrochemical sensor for carbendazim is 3.3 ng / mL.

[0026] Beneficial technical effects:

[0027] In the preparation method of the present invention, MXene is used as a carrier, platinum nanoparticles (PtNPs) are embedded in the MXene interlayer and surface through a reduction reaction, and then the electroactive molecule MB is introduced through electrostatic interaction to form a MXene@MB / PtNPs composite material, and then the MXene@MB / PtNPs composite material is used to modify the glassy carbon electrode to obtain a MXene@MB / PtNPs electrochemical sensor, thereby enhancing the conductivity and adsorption capacity of the glassy carbon working electrode; the loading of PtNPs can further improve the conductivity and catalytic activity of the composite material; in addition, the electroactive molecule MB embedded in MXene can not only inhibit the aggregation of MXene flakes and improve the electron transfer performance of the material, but also serve as an internal probe to form a ratio sensing strategy;

[0028] The MXene@MB / PtNPs electrochemical sensor of the present invention is used as a ratio electrochemical sensor for detecting carbendazim, and has the advantages of fast detection speed, high sensitivity, wide linear range, high accuracy, low detection limit, etc., and is also anti-interference and has good repeatability, and has potential application prospects in the field of agricultural product quality detection.

[0029] The MXene@MB / PtNPs ratio electrochemical sensor of the present invention can achieve highly sensitive ratio detection of carbendazim, and the sensor exhibits a wide linear range of 10 to 30,000 ng / mL and an extremely low detection limit of 3.3 ng / mL. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Figure 1 is a schematic diagram of the construction principle of the MXene@MB / PtNPs electrochemical sensor of the present invention, wherein Figure A is a schematic diagram of the construction principle of the MXene@MB / PtNPs composite material; Figure B is a schematic diagram of the construction principle of the MXene@MB / PtNPs / GCE;

[0031] Figure 2 The DPV response curves of CBZ standard solutions with different concentrations are shown in Figure 1. -8 g / mL,8×10 -8 g / mL,5×10 -7 g / mL,1×10 -7 g / mL,3×10 -7 g / mL,5×10 -7 g / mL,1×10-6 g / mL,1.5×10 -6 g / mL,2×10 -6 g / mL,2.5×10 -6 g / mL and 3×10 -5 g / mL;

[0032] Figure 3 is the ratio of DPV peak current I CBZ / I MB Linear relationship diagram of the standard curve equation plotted against CBZ concentration, where the abscissa represents the carbendazim concentration;

[0033] Figure 4 DPV current response comparison diagram of GCE, MXene / GCE, MXene / PtNPs / GCE and MXene@MB / PtNPs / GCE in 0.1M PBS (pH 6.0) containing 5.0μg / mL CBZ, and MXene@MB / PtNPs / GCE in 0.1M PBS (pH 6.0) containing 10.0μg / mL CBZ;

[0034] Figure 5 The figure shows the effect of changing the H2PtCl6 concentration on the DPV current response in 0.1M PBS (pH 6.0) containing 1.0 μg / mL CBZ. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present invention will be described clearly and completely below in combination with the embodiments of the present invention and the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. All other embodiments obtained by ordinary technicians in this field without creative work based on the embodiments of the present invention are within the scope of protection of the present invention.

[0036] Unless otherwise specifically stated, the numerical value set forth in these embodiments does not limit the scope of the present invention. The technology and method known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology and method should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values.

[0037] The experimental methods in the following examples without specifying specific conditions are usually measured in accordance with national standards; if there is no corresponding national standard, the method is carried out in accordance with the general standard requirements or general methods.

[0038] Example 1

[0039] The preparation method of MXene@MB / PtNPs electrochemical sensor comprises the following steps:

[0040] S1. A glassy carbon electrode (GCE) with a diameter of 3 mm was polished with 0.3 μm and 0.05 μm aluminum oxide powders, and then ultrasonicated in ethanol and water to remove surface residues, and then dried at room temperature;

[0041] S2. Preparation of MXene@MB / PtNPs composite materials:

[0042] ① Disperse 15 mg of MXene in 10 mL of pure water and ultrasonically treat for 30 minutes to obtain solution A; add 100 μL of 10 mM H2PtCl6 solution to solution A, ultrasonically treat for 10 minutes, then add 0.2 mL of formic acid, stir at room temperature for 16 hours, centrifuge, wash and dry to obtain MXene / PtNPs powder;

[0043] ② Disperse 10 mg of MXene / PtNPs powder in 10 mL of pure water and ultrasonically treat for 10 minutes to obtain solution B; add 10 mg of MB to solution B, stir for 1 hour at room temperature, centrifuge, wash and dry to obtain MXene@MB / PtNPs composite material powder. The schematic diagram of the construction of MXene@MB / PtNPs composite material is shown in the figure. Figure 1 As shown in Figure A;

[0044] S3, dispersing 5 mg of the above MXene@MB / PtNPs composite material powder in 5 mL of pure water to obtain a MXene@MB / PtNPs solution with a concentration of 1 mg / mL;

[0045] 6 μL of 1 mg / mL MXene@MB / PtNPs solution was added dropwise onto the treated GCE and dried at room temperature to obtain MXene@MB / PtNPs / GCE, which is the MXene@MB / PtNPs electrochemical sensor, which is used as a ratio electrochemical sensor for detecting carbendazim. The construction principle of MXene@MB / PtNPs / GCE is as follows Figure 1 As shown in Figure B.

[0046] Comparative Example 1

[0047] This case is the preparation of MXene / GCE: 5 mg of MXene powder was dispersed in 5 mL of pure water to obtain a MXene solution with a concentration of 1 mg / mL, 6 μL of the MXene solution of this concentration was dripped onto the treated GCE (treated with the same method as S1 in Example 1), and dried at room temperature to obtain MXene / GCE, which was used as a ratio electrochemical sensor for detecting carbendazim.

[0048] Comparative Example 2

[0049] This case is the preparation of MXene / PtNPs / GCE: 5 mg of MXene / PtNPs powder (same as ① in S2 of Example 1) was dispersed in 5 mL of pure water to obtain a MXene / PtNPs solution with a concentration of 1 mg / mL, 6 μL of the MXene / PtNPs solution of this concentration was dripped onto the treated GCE (treated with the same treatment as S1 in Example 1), and dried at room temperature to obtain MXene / PtNPs / GCE, which was used as a ratio electrochemical sensor for detecting carbendazim.

[0050] Example 2

[0051] The detection method of carbendazim comprises the following steps:

[0052] (1) Carbendazim CBZ was diluted with PBS buffer (0.1 M, pH 6.0) to form a series of standard solutions with different concentrations. The concentrations of the series of CBZ standard solutions were 1×10 -8 g / mL,8×10 -8 g / mL,5×10 -7 g / mL,1×10 -7 g / mL,3×10 -7 g / mL,5×10 -7 g / mL,1×10 -6 g / mL,1.5×10 -6 g / mL,2×10 -6 g / mL,2.5×10 -6 g / mL and 3×10 - 5 g / mL;

[0053] In a three-electrode system, a plurality of MXene@MB / PtNPs electrochemical sensors, a reference electrode and a counter electrode prepared according to the preparation method described in Example 1 are placed in the above-mentioned CBZ standard solution at the same time, and one concentration of CBZ standard solution corresponds to one MXene@MB / PtNPs electrochemical sensor; among the three electrodes, the MXene@MB / PtNPs electrochemical sensor (i.e., MXene@MB / PtNPs / GCE) is used as the working electrode, the Ag / AgCl (saturated KCl) electrode is used as the reference electrode, and the platinum wire is used as the counter electrode. Differential pulse voltammetry (DPV) scanning is performed to detect that a series of corresponding concentrations of CBZ standard solutions have two peak currents, namely, the peak current I MB and peak current I CBZ ;

[0054] The DPV response diagrams corresponding to the CBZ standard solutions with different concentrations are shown in the figure below: Figure 2 As shown by Figure 2 It can be seen that with the increase of carbendazim concentration, the peak current ratio I CBZ / I MB gradually rise;

[0055] (2) Using a series of concentrations of CBZ standard solution as the horizontal axis, the peak current ratio I in the DPV curve was detected. CBZ / I MB As the vertical axis, establish the ratio of carbendazim concentration to peak current I CBZ / I MB The standard curve of

[0056] The concentrations of the carbendazim standard solution are taken as the abscissa, denoted as C CBZ , with a peak current I CBZ With the peak current I MB The ratio is the ordinate, denoted as I CBZ / I MB , draw the standard curve, and obtain the standard curve equation after linear fitting;

[0057] According to the DPV peak current ratio I CBZ / I MB The linear relationship diagram of the standard curve equation drawn with CBZ concentration is as follows Figure 3 As shown by Figure 3 It can be seen that the peak current ratio I CBZ / I MB The standard linear curve between the concentration of carbendazim and CBZ / I MB =0.071+0.376C CBZ (R 2=0.994), the linear range was 10 ng / mL to 30 μg / mL, and the detection limit was 3.3 ng / mL;

[0058] (3) Actual testing:

[0059] The MXene@MB / PtNPs electrochemical sensor of Example 1 was applied to the spiked detection of different concentrations of carbendazim in actual sample lettuce, and the detection process was as follows: first, the lettuce purchased from the local market was chopped and filtered with a 0.2 μm nylon membrane, and after centrifugation, it was diluted 100 times with a 0.1 M PBS buffer solution to obtain a sample treatment solution to be tested, and 5 mL was taken for detection;

[0060] In the three-electrode system, the MXene@MB / PtNPs electrochemical sensor prepared in Example 1 (i.e., MXene@MB / PtNPs / GCE) was used as the working electrode, the Ag / AgCl (saturated KCl) electrode was used as the reference electrode, and the platinum wire was used as the counter electrode. The three electrodes were simultaneously placed in 5 mL of the sample treatment solution to be tested, and differential pulse voltammetry (DPV) scanning was performed to measure the peak current I CBZ With the peak current I MB , substitute into the standard linear curve I CBZ / I MB =0.071+0.376C CBZ (R 2 =0.994), the concentration information of carbendazim in lettuce was calculated, as shown in the following Table 1.

[0061] Table 1 Detection results of the constructed ratiometric electrochemical sensor for CBZ in lettuce samples

[0062]

[0063] (Note: “-” means carbendazim was not detected)

[0064] The results in Table 1 show that the constructed ratio electrochemical sensor can achieve high-sensitivity and high-precision ratio detection of carbendazim, and the relative standard deviation is controlled within 5%.

[0065] The blank GCE, MXene / GCE (Comparative Example 1), MXene / PtNPs / GCE (Comparative Example 2) and MXene@MB / PtNPs / GCE (Example 1) were respectively subjected to DPV current response tests in 0.1M PBS (pH 6.0) containing 5.0 μg / mL CBZ and MXene@MB / PtNPs / GCE in 0.1M PBS (pH 6.0) containing 10.0 μg / mL CBZ. The results are shown in Figure 4, where GCE, MXene / GCE, MXene / PtNPs / GCE and MXene@MB / PtNPs / GCE represent glassy carbon electrode, MXene-modified glassy carbon electrode, MXene / PtNPs-modified glassy carbon electrode and MXene@MB / PtNPs composite-modified glassy carbon electrode, respectively. Figure 4 It can be seen that the current response of the glassy carbon electrode modified with MXene@MB / PtNPs (MXene@MB / PtNPs / GCE) is much higher than the detection results of other electrodes. It can be seen that the glassy carbon electrode modified with MXene@MB / PtNPs composite materials can significantly improve the detection effect.

[0066] The working principle of the MXene@MB / PtNPs electrochemical sensor of the present invention is: MXene has the characteristics of high conductivity, large specific surface area, good hydrophilicity, excellent mechanical strength, etc., and has good adsorption capacity for CBZ, which is of great significance for improving the detection ability of CBZ. With MXene as the substrate, platinum nanoparticles (PtNPs) are embedded in the MXene interlayer and surface through a reduction reaction, and then the electroactive molecule MB is introduced through electrostatic interaction to form a MXene@MB / PtNPs composite material. The loading of PtNPs can further improve the conductivity and catalytic activity of the composite material. In addition, the electroactive molecule MB embedded in MXene can not only inhibit the aggregation of MXene flakes and improve the electron transfer performance of the material, but also serve as an internal probe to form a ratio sensing strategy. Due to the synergistic effect of the materials, the prepared MXene@MB / PtNPs composite material has the characteristics of large specific surface area, rich effective active sites, and high conductivity, providing more mass transfer channels and improving the mass transfer capacity and catalytic activity of CBZ. When CBZ and MB undergo redox reaction, with the help of the excellent performance of the modified electrode, two obvious redox peaks will appear during the electrochemical detection process, realizing the qualitative ratio detection of carbendazim. As the concentration of CBZ increases, the current intensity of CBZ increases significantly while the current intensity of MB does not change significantly, so the ratio of the peak current corresponding to the CBZ concentration can be compared. CBZ / I MB The concentration of CBZ in the sample to be tested was obtained using a standard curve.

[0067] Example 3

[0068] The preparation of the electrochemical sensor in this case is the same as that in Example 1, except that the concentration of the H2PtCl6 solution is changed to 4mM, 7mM, 10mM, 13mM, and 16mM; then the DPV response is detected according to the detection method of Example 2, and the results are as follows Figure 5As shown, when the concentration of H2PtCl6 solution is 10mM, the DPV response is the highest and the detection effect is the best; when the concentration of H2PtCl6 is greater than 13mM, the detection effect is poor.

[0069] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for preparing a MXene@MB / PtNPs electrochemical sensor, characterized in that: The steps include: S1. Surface polishing and cleaning of glassy carbon electrode; S2. Preparation of MXene@MB / PtNPs composite materials: ① Add H2PtCl6 solution to the aqueous dispersion of MXene, and after uniform dispersion, add formic acid, stir and react at room temperature, and obtain MXene / PtNPs material after solid-liquid separation, washing and drying; ② Forming a water dispersion of MXene / PtNPs material, adding methylene blue, stirring the reaction at room temperature, and obtaining a MXene@MB / PtNPs composite material after solid-liquid separation, washing, and drying; S3. Dispersing the MXene@MB / PtNPs composite material in water to form a MXene@MB / PtNPs solution, coating the solution on the surface of the glassy carbon electrode, and drying at room temperature to obtain a MXene@MB / PtNPs electrochemical sensor.

2. The method for preparing the MXene@MB / PtNPs electrochemical sensor according to claim 1, characterized in that: The concentration of the MXene@MB / PtNPs solution is 0.05-5 mg / mL; 4-8 μL of the MXene@MB / PtNPs solution is dripped onto the glassy carbon electrode.

3. The method for preparing the MXene@MB / PtNPs electrochemical sensor according to claim 1, characterized in that: Ultrasonic treatment is used to form a corresponding aqueous dispersion, and the ultrasonic treatment time is 10-40 minutes; the MXene aqueous dispersion, the H2PtCl6 solution and the formic acid are stirred and reacted at room temperature for 14-20 hours; the MXene / PtNPs material aqueous dispersion and the methylene blue are stirred and reacted at room temperature for 1-4 hours.

4. The method for preparing the MXene@MB / PtNPs electrochemical sensor according to claim 1, characterized in that: The volume ratio of the MXene aqueous dispersion, the H2PtCl6 solution, and the formic acid is 5-50mL:40-160μL:0.2-2mL; the mass ratio of the MXene / PtNPs material to the methylene blue is 10-100:0.1-10.

5. The method for preparing the MXene@MB / PtNPs electrochemical sensor according to claim 4, characterized in that: The ratio of MXene to water in the MXene aqueous dispersion is 15-150 mg: 5-50 mL; the concentration of the H2PtCl6 solution is in the range of 8-13 mM; the ratio of MXene / PtNPs material to tax in the MXene@MB / PtNPs solution is 10-100 mg: 5-50 mL.

6. The method for preparing the MXene@MB / PtNPs electrochemical sensor according to any one of claims 1 to 5, characterized in that: The diameter of the glassy carbon electrode is 3 mm; the glassy carbon electrode is polished with aluminum oxide powder, and the particle sizes of the aluminum oxide powder are 0.3 μm and 0.05 μm.

7. A MXene@MB / PtNPs electrochemical sensor prepared according to the preparation method according to any one of claims 1 to 6.

8. A method for detecting carbendazim, characterized in that: The steps include: (1) preparing a series of carbendazim standard solutions with different concentrations, and placing a plurality of MXene@MB / PtNPs electrochemical sensors, reference electrodes, and counter electrodes prepared by the above preparation method in the carbendazim standard solutions at the same time, wherein one concentration of the carbendazim standard solution corresponds to one MXene@MB / PtNPs electrochemical sensor; In a three-electrode system, the MXene@MB / PtNPs electrochemical sensor was used as the working electrode, the Ag / AgCl electrode was used as the reference electrode, and the platinum wire was used as the counter electrode. The differential pulse voltammetry (DPV) method was used to detect the carbendazim standard solution corresponding to a series of concentrations, and the peak currents were I MB and peak current I CBZ ; (2) A series of concentrations of the carbendazim standard solution are used as the horizontal axis, denoted as C CBZ , with a peak current I CBZ With the peak current I MB The ratio is the ordinate, denoted as I CBZ / I MB , draw the standard curve, and obtain the standard curve equation after linear fitting; (3) The MXene@MB / PtNPs electrochemical sensor prepared by the above preparation method is placed in the test solution, and detection is performed using differential pulse voltammetry in a three-electrode system according to the method of step (1), the measured results are recorded, and substituted into the standard curve equation to obtain the concentration of carbendazim in the test solution.

9. The method for detecting carbendazim according to claim 8, characterized in that: The concentration range of a series of carbendazim standard solutions is 1×10 -8 ~3×10 -5 g / mL; when testing the test solution, adjusting the pH value of the test solution to 5.5-6.5; The standard curve equation is: CBZ / I MB =0.071+0.376×C CBZ , R 2 =0.994, the linear range is 10 ng / mL to 30 μg / mL, and the detection limit concentration of the MXene@MB / PtNPs electrochemical sensor for carbendazim is 3.3 ng / mL.

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