A modified electrode and a preparation method of a dual-template molecular imprinting electrochemical sensor

Abstract

The invention discloses a modified electrode and a preparation method of a dual-template molecular imprinting electrochemical sensor, belonging to the field of electrochemical sensors. The invention aims to solve the problems that the traditional dopamine and chlorpromazine detection process is cumbersome, the detection equipment is expensive, the operation requirements for the detection personnel are high, and the sample pretreatment preparation process is complicated. The method of the invention is as follows: Boron nitride nanosheets (HBNNS materials) and multi-walled carbon nanotubes (MWCNTs) are dispersed with anhydrous ethanol respectively and then ultrasonically mixed, the supernatant is removed after centrifugation, and the sediment is vacuum dried to obtain a HBNNS / MWCNTs composite material; the HBNNS / MWCNTs material is mixed with a chitosan solution until uniform to obtain a mixed solution, and the mixed solution is dropwise coated on a polished electrode, and dried to obtain a modified electrode. The invention can be applied to the simultaneous analysis of dopamine and chlorpromazine content.

Description

Technical Field

[0001] The invention belongs to the field of electrochemical sensors, and in particular, relates to a method for preparing a modified electrode and a method for preparing an electrochemical sensor based on double-template molecular imprinting. Background Art

[0002] Dopamine (DA) is an important endogenous neurotransmitter that plays an important role in the human metabolic, cardiovascular and hormonal systems. It has a great influence on the control of brain neurocognition and diet. When the human body lacks dopamine, it loses the ability to feel happiness, which can lead to depression in severe cases, while excessive dopamine increases the risk of mental illness. Whether dopamine secretion is abnormal can be used as a diagnostic basis for diseases such as schizophrenia and Alzheimer's disease. Chlorpromazine (CPZ) is a representative substance of phenothiazines. It can be used as a blocker of central dopamine receptors, acting on the central nervous system, and has multiple pharmacological effects such as antipsychotic, cooling, and anesthesia. However, excessive use of chlorpromazine can cause damage to human health, leading to lesions of the liver and kidneys, and abnormal heart rhythms. Therefore, constructing a sensitive and simple method for simultaneous detection of dopamine and chlorpromazine is of great significance for clinical diagnosis.

[0003] At present, many detection methods are used to detect dopamine and chlorpromazine respectively. Such as optical analysis, chromatography, chromatography-tandem mass spectrometry, etc. The optical analysis method is simple to operate, but it has disadvantages such as low sensitivity and complex testing. Chromatography and its tandem mass spectrometry technology have good sensitivity, but there are still problems such as expensive equipment and long time in the analysis process. There are literature reports that dopamine or chlorpromazine can be detected by electrochemical methods, but there are also problems with poor sensitivity and selectivity. In conventional molecular imprinting technology, a single template molecule and a single functional monomer are used.

[0004] In summary, although dopamine and chlorpromazine can be determined by analytical methods such as high performance liquid chromatography and spectrophotometry, these methods have disadvantages such as cumbersome preparation. The electrochemical method is a new technology with advantages such as simple preparation process, fast response and low cost. Since dopamine and chlorpromazine both play an important role in the regulation of the nervous system, it is of great significance to develop a detection method with good selectivity and high sensitivity for the simultaneous determination of dopamine and chlorpromazine. Summary of the invention

[0005] The present invention aims to solve the technical problems such as the complicated detection process of traditional dopamine and chlorpromazine, the expensive detection equipment, the high operating requirements for detection personnel, and the complicated sample pretreatment preparation process, and provides a method for preparing a modified electrode and a method for preparing a dual-template molecular imprinting electrochemical sensor.

[0006] In order to solve the above technical problems and overcome the shortcomings and deficiencies of the prior art, the present invention adopts the following technical solutions:

[0007] The object of the present invention is to provide a method for preparing a modified electrode, comprising the following steps:

[0008] Step 1: Preparation of boron nitride nanosheets / multi-walled carbon nanotubes (HBNNS / MWCNTs) materials:

[0009] Boron nitride nanosheets (HBNNS material) and multi-walled carbon nanotubes (MWCNTs) are dispersed in anhydrous ethanol and then ultrasonically mixed. After centrifugation, the supernatant is removed and the sediment is vacuum dried to obtain the HBNNS / MWCNTs composite material.

[0010] Step 2: Preparation of modified electrode:

[0011] The HBNNS / MWCNTs material prepared by the method in step 1 is mixed with the chitosan solution until uniform to obtain a mixed solution, and the mixed solution is dropped on the polished electrode and dried to obtain a modified electrode.

[0012] It is further defined that in step one, the boron nitride nanosheets (HBNNS material) are prepared according to the following steps: a certain amount of boron nitride is weighed and dispersed in isopropanol to obtain a boron nitride solution, which is stirred at a temperature of 40°C to 80°C for at least 24 hours, the stirred boron nitride solution is ultrasonicated, and then centrifuged to retain the white powder, and then acetone is added for centrifugal washing 3-5 times. After centrifugation, the sediment is dried to obtain the boron nitride nanosheets (HBNNS).

[0013] It is further defined that during the preparation of the boron nitride nanosheets, the boron nitride is dispersed in the isopropanol at a ratio of (80 mg-150 mg) to (30 mL-80 mL) of the mass of the boron nitride to the volume of the isopropanol.

[0014] It is further defined that during the preparation process of the boron nitride nanosheets, the ultrasonic frequency is 40 KHz and the ultrasonic time is 8 h-12 h.

[0015] It is further defined that during the preparation process of the boron nitride nanosheets, drying is performed in a vacuum drying oven at 60° C. to 80° C. for 24 h to 48 h.

[0016] It is further defined that in step one, boron nitride nanosheets are dispersed in anhydrous ethanol at a concentration of 0.1 mg / mL-2 mg / mL; multi-walled carbon nanotubes are dispersed in anhydrous ethanol at a concentration of 1 mg / mL-4 mg / mL; and the boron nitride nanosheets and multi-walled carbon nanotube dispersion are mixed at a volume ratio of 1:5-5:1.

[0017] It is further defined that in step 1, the centrifugation is performed at a rotation speed of 12000 rpm for 10 minutes.

[0018] It is further defined that in step 1, the rotation speed of the centrifugal washing is 12000 rpm, and each centrifugal washing lasts 10 minutes.

[0019] It is further defined that in step 1, the ultrasonic frequency is 40 KHz; and the ultrasonic time is 5h-15h.

[0020] It is further defined that in step 1, the sediment is dried in a vacuum drying oven at 60° C. to 80° C., and the drying time is controlled at 24 h to 48 h.

[0021] It is further defined that in step 2, the mass percentage concentration of the chitosan solution is 0.01%-2%; preferably, the mass percentage concentration of the chitosan solution is 0.5%-1.5%; wherein the chitosan solution can be prepared by dissolving chitosan in an acetic acid solution with a mass percentage concentration of 0.5% to 2%.

[0022] It is further defined that in step 2, the HBNNS / MWCNTs material and the chitosan solution are mixed in a volume ratio of 1:1 to 3:1.

[0023] It is further defined that in step 2, drying is carried out in an oven at 40° C.-70° C. for 10 min-30 min.

[0024] It is further defined that in step 2, the electrode is one of a glassy carbon electrode, a gold electrode, and a platinum electrode.

[0025] Further defined, in step 2, the electrode polishing method is as follows: polishing the glassy carbon electrode on the suede with alumina polishing powder with a particle size of 0.5 μm and 0.05 μm, respectively, and rinsing the electrode surface with deionized water after polishing. Scanning the cyclic voltammogram in a 0.05M potassium ferrocyanide solution containing 0.1M KCl to test the performance of the electrode.

[0026] The present invention also provides a modified electrode prepared by any of the above methods.

[0027] The present invention also provides a method for preparing a dual-template molecular imprinting electrochemical sensor, comprising the following steps:

[0028] The modified electrode prepared by any of the above methods is placed in a phosphate buffer containing dopamine, chlorpromazine and o-phenylenediamine, electrochemically polymerized to form a film, naturally air-dried and eluted to obtain the sensor.

[0029] It is further defined that the molar ratio of dopamine, chlorpromazine and o-phenylenediamine is (1-2):(1-2):(0.5-2); for example, the molar ratio of dopamine, chlorpromazine and o-phenylenediamine can be 1:1:0.5, 1:1:1, 1:1:2, 1:2:1 or 2:1:1. Preferably, the molar ratio of dopamine, chlorpromazine and o-phenylenediamine is 1:1:1.

[0030] It is further defined that the pH value of the phosphate buffer is 6.0-9.0; preferably, the pH value is 7.0.

[0031] Further, the electrochemical polymerization film forming process parameters are as follows: the potential range is -0.2V-1.0V, the number of scanning circles is 15-30 circles, and the scanning speed can be 0.05V·s -1 -1V·s -1 .

[0032] It is further defined that the elution method is soaking in an eluent. The eluent is a methanol-acetic acid solution with a volume ratio of 4:1. The soaking time is 1 min to 10 min. Preferably, the elution time is 2 min.

[0033] The present invention also provides a dual-template molecular imprinting electrochemical sensor prepared by any of the above methods.

[0034] The present invention uses HBNNS / MWCNTs materials to modify the electrode to increase the effective specific surface area of ​​the electrode and the electron transmission rate. The two targets are used as template molecules, and after reacting with the functional monomers, the diversity of the imprinted cavities in the molecular imprinted membrane can be increased. At the same time, since the introduction of the dual template molecules can optimize the cavity size, it is easier to form more accurate imprinted holes than a single template molecule, and the affinity of the molecular imprinted membrane is increased, thereby overcoming the difficulty of simultaneously measuring two substrates in a complex matrix.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] The present invention modifies the electrode with HBNNS / MWCNTs material, and the current of the modified electrode is about 7.5 times that of the bare electrode, and the electrochemical performance is significantly improved. The dual-template molecular imprinting electrochemical sensor prepared by using the HBNNS / MWCNTs material modified electrode is used to detect the mixed solution containing dopamine and chlorpromazine, and can simultaneously analyze dopamine in the concentration range of 0.6μM-100μM and chlorpromazine in the concentration range of 0.2μM-100μM.

[0037] The dual template molecular imprinting electrochemical sensor prepared by the present invention is based on HBNNS / MWCNTs material (see the attached embodiment Figure 1), a molecular imprinting electrochemical sensor for simultaneously identifying dopamine and chlorpromazine with high sensitivity, having good sensitivity (see Example Attachment Figure 2-3 ), and strong anti-interference performance (see Appendix Figure 4 ).

[0038] The dual-template molecular imprinting electrochemical sensor prepared by the present invention is used for simultaneous specific recognition and analysis of dopamine and chlorpromazine. The detection method is simple to operate, rapid, and has low detection cost. The material preparation of the modified electrode is simple and inexpensive, which overcomes the technical difficulties such as the traditional dopamine and chlorpromazine detection process is relatively cumbersome, the detection equipment is relatively expensive, the operation requirements for the detection personnel are high, and the sample pretreatment preparation process is complicated. The present invention selects o-phenylenediamine as a functional monomer and dopamine and chlorpromazine as dual-template molecules. Compared with traditional single target detection, the detection of the target in a complex matrix has better sensitivity and stronger anti-interference. The dual-template molecular imprinting electrochemical sensor prepared by the present invention can achieve high-sensitivity recognition and specific response to the target in a neutral environment.

[0039] In order to further understand the features and technical contents of the present invention, please refer to the following detailed description and drawings of the present invention. However, the attached drawings are only provided for reference and illustration and are not intended to limit the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is the scanning electron microscope characterization image of HBNNS / MWCNTs material;

[0041] Figure 2 Cyclic voltammograms of different materials in potassium ferrocyanide solution;

[0042] Figure 3 This is a linear graph of the dual-template molecular imprinting electrochemical sensor prepared in Example 1 responding simultaneously to different concentrations of dopamine (DA) and chlorpromazine (CPZ);

[0043] Figure 4 These are the anti-interference performance test results of the dual-template molecular imprinting electrochemical sensor prepared in Example 1 for detecting dopamine (DA) and chlorpromazine (CPZ). DETAILED DESCRIPTION

[0044] The present invention will be described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, and do not limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0045] Dopamine and chlorpromazine detection performance test:

[0046] In a mixed solution of 5mM K3[Fe(CN)6] and 0.1M KCl, the electrode modified with the test material was used as the working electrode, the Ag / AgCl electrode was used as the reference electrode, and the platinum wire electrode was used as the auxiliary electrode. The electrochemical signal was detected by differential pulse voltammetry for testing.

[0047] Anti-interference performance test:

[0048] In a mixture of 5mM K3[Fe(CN)6] and 0.1M KCl, the test material was used as the working electrode, the Ag / AgCl electrode was used as the reference electrode, and the platinum wire electrode was used as the auxiliary electrode. The electrochemical signal was detected by differential pulse voltammetry, and the electrochemical response signals of potassium chloride, ascorbic acid, folic acid, glucose and uric acid were detected. The anti-interference performance of the method was evaluated by the current change.

[0049] Embodiment 1: This embodiment comprises the following steps:

[0050] Step 1: Preparation of HBNNS nanosheets:

[0051] 100 mg of boron nitride was uniformly dispersed in 50 mL of isopropanol, and stirred at a temperature of 50°C and a speed of 500 rpm for 24 hours; the stirred boron nitride solution was ultrasonically treated at an ultrasonic frequency of 40 KHz for 10 hours, and then centrifuged at a speed of 12000 rpm for 10 minutes to retain white powder; acetone was then added for centrifugal washing 3 times, the centrifugal washing speed was 12000 rpm, and each centrifugal washing was 10 minutes. The sediment after centrifugation was placed in a vacuum drying oven and dried at 60°C for 24 hours to obtain HBNNS nanosheets;

[0052] Step 2: Preparation of HBNNS / MWCNTs materials:

[0053] The HBNNS nanosheets and MWCNTs prepared in step 1 were dispersed in anhydrous ethanol respectively until they were uniform. The concentration of the HBNNS nanosheet material in the ethanol dispersion was 1 mg / mL, and the concentration of the MWCNTs material in the ethanol dispersion was 2 mg / mL. The HBNNS nanosheet dispersion and the MWCNTs dispersion were then ultrasonically mixed for 8 hours at a volume ratio of 2:1, with an ultrasonic frequency of 40 KHz, and the supernatant was removed after centrifugation at a speed of 12000 rpm for 10 minutes. The sediment was placed in a vacuum drying oven at 60°C and dried for 24 hours. The resulting precipitate was the HBNNS / MWCNTs material (see Figure 1 ).

[0054] Step 3: Preparation of modified electrode:

[0055] The HBNNS / MWCNTs material prepared in step 2 was mixed with a chitosan solution with a mass percentage concentration of 1% in a volume ratio of 3:1 until uniform, and then the mixed solution was drop-coated (the amount of drop-coated was 8 μL) on a polished glassy carbon electrode (the diameter of the glassy carbon core was 3 mm, purchased from Tianjin Aida Hengsheng Technology Development Co., Ltd., model: GC130), and placed in an oven at 50°C for drying for 15 minutes to obtain a modified electrode.

[0056] The polishing method is as follows: the glassy carbon electrode is polished on the suede with aluminum oxide polishing powder with a particle size of 0.5 μm and 0.05 μm in turn, and the electrode surface is rinsed with deionized water after polishing. The cyclic voltammogram is scanned in a 0.05 M potassium ferrocyanide solution containing 0.1 M KCl to test the performance of the electrode.

[0057] Step 4. Preparation of dual-template molecular imprinting electrochemical sensor: The modified electrode was placed in a phosphate buffer solution (volume 15 mL) at pH 7.0, which contained 1 mmol dopamine, 1 mmol chlorpromazine and 1 mmol o-phenylenediamine, and electrochemical polymerization was performed using cyclic voltammetry in the range of -0.2 V to 1.0 V, with 10 scans and a scan rate of 0.05 V·s -1 The electrode was naturally air-dried and placed in a methanol-acetic acid mixture (V / V=4:1) for elution. The elution time was 2 min, and a molecular imprinting electrochemical sensor was obtained.

[0058] The detection performance test results of the dual template molecular imprinting electrochemical sensor provided in Example 1 are as follows: Figure 3 As shown. Figure 3 It can be seen that the dual-template molecular imprinting electrochemical sensor based on HBNNS / MWCNTs material modified glassy carbon electrode is used for the detection of dopamine and chlorpromazine. Dopamine can be detected in the concentration range of 0.6-100 μM, and chlorpromazine can be detected in the concentration range of 0.2-100 μM. This shows that the dual-template molecular imprinting sensor prepared by the present invention can accurately determine dopamine and chlorpromazine at the same time.

[0059] The anti-interference performance test results of the dual-template molecular imprinting electrochemical sensor provided in Example 1 are as follows: Figure 4 The current differences of potassium chloride, ascorbic acid, folic acid, glucose and uric acid are respectively one-half, one-third, one-eighth, one-quarter and one-third of the current differences of dopamine and chlorpromazine, indicating that the molecular imprinting electrochemical sensor of the present invention has specific recognition for dopamine and chlorpromazine.

[0060] 1. (Glass carbon) bare electrode a, HBNNS / MWCNTs material modified (glass carbon) electrode b, HBNNS nanosheet modified (glass carbon) electrode c and MWCNTs material modified (glass carbon) electrode d (Example 1).

[0061] (1) Comparison of cyclic voltammograms of the above materials in potassium ferrocyanide solution

[0062] Figure 2 The cyclic voltammograms of the above materials in potassium ferrocyanide solution, where a is a bare electrode, b is an electrode modified with HBNNS / MWCNTs materials, c is an electrode modified with HBNNS nanosheets, and d is an electrode modified with MWCNTs.

[0063] Comparing the cyclic voltammetric performance of the above materials in potassium ferrocyanide solution, the current value of the electrode a modified by the HBNNS / MWCNTs material is significantly higher than that of the bare glassy carbon electrode b, indicating that the HBNNS / MWCNTs material has been loaded on the bare glassy carbon electrode b, the current value increases, and the electrochemical performance improves; and the current value of the electrode a modified by the HBNNS / MWCNTs material is higher than that of the electrode c modified by the HBNNS nanosheet and the electrode d modified by the MWCNTs material. It can be seen that the electrochemical sensor based on the HBNNS / MWCNTs material provided by the present invention improves the conductivity of the commercially available electrode substrate.

[0064] 2. Optimization of the molar ratio of dopamine, chlorpromazine and o-phenylenediamine

[0065] The present invention found in the electrochemical method detection of dopamine and chlorpromazine by the dual-template molecular imprinting electrochemical sensor based on HBNNS / MWCNTs that the ratio of dual-template molecules to functional monomers is one of the main factors affecting the electrochemical performance. By optimizing the sensitivity and selective response of the electrochemical sensor, an electrochemical sensor with specific response to dopamine and chlorpromazine was constructed.

[0066] Table 1 Optimization test results of molar ratio of dopamine, chlorpromazine and o-phenylenediamine

[0067]

[0068] In Example 1 of the present invention, after comparing multiple groups of ratios, it was found that the electrochemical polymerization of a single functional monomer had no effect, or the current difference was less than that of a bifunctional monomer under the optimal ratio. Combined with data analysis, the present invention uses bifunctional monomers to improve the sensitivity of molecular imprinting electrochemical sensors.

[0069] The ratio of template to functional monomer was investigated, and the experimental results showed that the molar ratio of dopamine, chlorpromazine and o-phenylenediamine had a great influence on the detection performance of dopamine and chlorpromazine. When the molar ratio of dopamine, chlorpromazine and o-phenylenediamine was 1:1:1, the prepared molecular imprinting electrochemical sensor had better performance and the current difference was the largest.

[0070] 3. pH Optimization of Preparation Conditions for Molecularly Imprinted Electrochemical Sensors

[0071] The present invention found in the electrochemical method detection experiment of dopamine and chlorpromazine by using a dual-template molecular imprinting electrochemical sensor based on HBNNS / MWCNTs that the pH of the phosphate buffer in the preparation of the molecular imprinting electrochemical sensor is one of the main factors affecting the sensor detection performance. By optimizing the sensitivity of the electrochemical sensor, an electrochemical sensor with specific response to dopamine and chlorpromazine was constructed.

[0072] Table 2 Optimization test results of phosphate buffer pH

[0073] Material No. pH Cyclic voltammetry current difference ΔI / percentage 1# (Example 1) 7.0 Maximum current difference 6# 6.0 38% of the maximum current difference 7# 8.0 46% of the maximum current difference 8# 9.0 65% of the maximum current difference

[0074] By comparison, it can be seen that the current difference of the electropolymer medium is relatively small under weak acidic and alkaline conditions, and the current difference increases significantly under neutral conditions. Under pH 7.0, the current difference is the largest, and the electrochemical performance is better. Therefore, the pH of the medium has a greater influence on the preparation of the dual-template molecular imprinting electrochemical sensor. The experimental results show that the pH of the preparation conditions of the dual-template molecular imprinting electrochemical sensor has a greater influence on the electrochemical performance of the molecular imprinting electrochemical sensor in detecting dopamine and chlorpromazine. When the medium conditions of the detection are neutral, the prepared dual-template molecular imprinting electrochemical sensor has better detection performance for dopamine and chlorpromazine.

[0075] 4. Optimization of preparation conditions of modified electrodes (differential effects on detection of dopamine and chlorpromazine)

[0076] (1) Preparation of HBNNS / MWCNTs material: Weigh a certain amount of boron nitride and disperse it in isopropanol, and stir it at 50°C; ultrasonically treat the stirred boron nitride solution, centrifuge it, retain the white powder, add acetone for centrifugal washing, and dry the sediment after centrifugation to obtain HBNNS nanosheets. Then, HBNNS nanosheets and MWCNTs are dispersed in ethanol respectively, and the concentration of HBNNS nanosheets in the ethanol dispersion is 0.1-2 mg / mL, and the concentration of MWCNTs in the ethanol dispersion is 1-4 mg / mL. Then, the above two dispersions are ultrasonically mixed at a volume ratio of 1:5-5:1, and the supernatant is removed after centrifugation. The sediment is placed in a vacuum drying oven at 60°C and dried. The obtained precipitate is the HBNNS / MWCNTs material. The results are shown in Tables 3 and 4.

[0077] Table 3 HBNNS / MWCNTs material ratio optimization test results

[0078]

[0079]

[0080] The results show that the raw material ratio is one of the influencing factors in the preparation of HBNNS / MWCNTs materials. When the concentration ratio of the reaction raw materials is 1:4, the current value is large. Under other concentration ratios, the current values ​​are all reduced, indicating that the electrochemical performance of the material prepared when the concentration ratio of the reaction raw materials is 1:4 is better.

[0081] Table 4 HBNNS / MWCNTs material preparation time optimization test results

[0082] Material No. Reaction time (h) Cyclic voltammetry current value I / μA 1# (Example 1) 8 Maximum peak current 15# 6 49% lower than the maximum peak current 16# 12 32% lower than the maximum peak current

[0083] The results show that the HBNNS / MWCNTs material prepared for 8 hours has better electrochemical performance.

[0084] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Anyone familiar with this technology can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the definition of the claims.

Claims

1. A dual-template molecular imprinting electrochemical sensor, the sensor is used for simultaneous detection of dopamine and chlorpromazine content, and the preparation method of the sensor comprises the following steps: Step 1, dispersing the boron nitride nanosheets HBNNS and the multi-walled carbon nanotubes MWCNTs with anhydrous ethanol, mixing, ultrasonically treating, centrifuging, and vacuum drying the sediment to obtain a HBNNS / MWCNTs composite material; Step 2: Mix the HBNNS / MWCNTs composite material prepared in step 1 with the chitosan solution, then drop-coat it on the polished electrode and dry it to obtain a modified electrode; Step 3: placing the modified electrode prepared in step 2 in a phosphate buffer solution containing dopamine, chlorpromazine and o-phenylenediamine, electrochemically polymerizing the electrode into a film, naturally air-drying the film, and eluting the film to obtain the sensor.

2. The sensor according to claim 1, characterized in that The boron nitride nanosheets are prepared according to the following steps: 80 mg to 150 mg of boron nitride is dispersed in 30 mL to 80 mL of isopropanol, stirred at 40° C. to 80° C. for at least 24 hours, then ultrasonicated for 8 hours to 12 hours, centrifuged, and the powder is washed by centrifugation with acetone and then dried to obtain the boron nitride nanosheets.

3. The sensor according to claim 1, characterized in that The ultrasonic frequency is 40KHz; the ultrasonic time is 5h-15h.

4. The sensor according to claim 1, characterized in that Boron nitride nanosheets are dispersed in anhydrous ethanol at a concentration of 0.1 mg / mL-2 mg / mL; multi-walled carbon nanotubes are dispersed in anhydrous ethanol at a concentration of 1 mg / mL-4 mg / mL; and the boron nitride nanosheets and multi-walled carbon nanotube dispersion are mixed at a volume ratio of 1:5-5:

1.

5. The sensor according to claim 1, characterized in that The mass percentage concentration of the chitosan solution is 0.01%-2%; the volume ratio of the HBNNS / MWCNTs composite material to the chitosan solution is 1:1-3:

1.

6. The sensor according to claim 1, characterized in that The electrode is a glassy carbon electrode, a gold electrode or a platinum electrode.

7. The sensor according to claim 1, characterized in that The molar ratio of dopamine, chlorpromazine and o-phenylenediamine is (1-2):(1-2):(0.5-2); the pH value of the phosphate buffer is 6.0-9.0; the electrochemical polymerization film forming process parameters are: the potential range is -0.2V-1.0V, the number of scans is 15-30, and the scan rate is 0.05V·s -1 -1V·s -1 .

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