A molecularly imprinted membrane electrochemical sensor and a preparation method thereof

Abstract

The application discloses a kind of molecularly imprinted film electrochemical sensor and preparation method thereof, first preparation hydroxylated multi-walled carbon nanotube modified electrode HCNT-GCE, molecularly imprinted polymer ITO-MIP, then molecularly imprinted polymer ITO-MIP drop coating is applied to the surface of hydroxylated multi-walled carbon nanotube modified electrode HCNT-GCE, after high-temperature solidification treatment, obtain MIP-OH-MWCNTs-GCE electrode, finally the MIP-OH-MWCNTs-GCE electrode obtained with reference electrode, working electrode is connected on electrochemical workstation, and forms molecularly imprinted film electrochemical sensor. The molecularly imprinted electrochemical sensor prepared by the design has very low detection limit, higher detection sensitivity, larger sensing area and better conductivity, and can better meet the detection requirement.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical sensor technology, specifically relating to a molecularly imprinted membrane electrochemical sensor and its preparation method, which is suitable for improving the detection sensitivity, sensing area and conductivity of molecularly imprinted membrane electrochemical sensors. Background Technology

[0002] Adrenaline (Ae), chemically known as (R)-4-(2-(methylamino)-1-hydroxyethyl)-1,2-benzenediol, is a catecholamine and a neurotransmitter and adrenocortical hormone. When humans or horses are subjected to certain stimuli (such as tension, excitement, or injury before a major competition), the body exhibits a "stress response." The adrenal medulla secretes adrenaline, while the adrenal cortex secretes glucocorticoids. Glucocorticoids promote glycogenolysis, causing a rise in blood sugar. This elevated blood sugar provides the body with sufficient energy in a short period to help cope with environmental stimuli and changes.

[0003] Many violations in international equestrian events are due to the administration of adrenaline to participating horses. However, adrenaline residues in horse blood are in the trace range, requiring high detection sensitivity. Molecularly imprinted electrochemical sensors have high sensitivity and are widely used for adrenaline detection. However, the detection sensitivity, sensing area, and conductivity of existing molecularly imprinted electrochemical sensors are poor and cannot meet the detection requirements. Summary of the Invention

[0004] The purpose of this invention is to address the aforementioned problems in the prior art by providing a molecularly imprinted membrane electrochemical sensor with higher detection sensitivity, sensing area, and conductivity, as well as a method for its preparation.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] A method for preparing a molecularly imprinted membrane electrochemical sensor, the method comprising:

[0007] S1. Preparation of hydroxylated multi-walled carbon nanotube-modified glassy carbon electrode OH-MWCNTs-GCE and molecularly imprinted polymer MIP, wherein the hydroxylated multi-walled carbon nanotube-modified glassy carbon electrode OH-MWCNTs-GCE is obtained by drop-coating a dispersion of hydroxylated multi-walled carbon nanotubes onto a polished glassy carbon electrode and then curing it at high temperature; the preparation steps of the molecularly imprinted polymer MIP include:

[0008] A1. Add mixture A dropwise to mixture B to react and obtain oligomeric silsesquioxane-Al2O3 composite sol. Mixture A is a mixed solution obtained by mixing water, glacial acetic acid, Al2O3 sol and anhydrous ethanol in the required proportion. Mixture B is an oligomeric silsesquioxane solution obtained by mixing methyltrimethoxysilane and anhydrous ethanol in the required proportion.

[0009] A2. Mix oligomeric silsesquioxane-Al2O3 composite sol, indium tin sol (ITO), and anhydrous ethanol in the required proportions and react to obtain an intermediate.

[0010] A3. The intermediate is mixed with the template molecule solution to obtain the molecularly imprinted polymer (MIP).

[0011] S2. Molecularly imprinted polymer (MIP) is drop-coated onto the surface of glassy carbon electrode OH-MWCNTs-GCE modified with hydroxylated multi-walled carbon nanotubes, and then subjected to high-temperature curing to obtain MIP-OH-MWCNTs-GCE electrode.

[0012] S3. Insert the MIP-OH-MWCNTs-GCE electrode, along with the reference electrode and the working electrode, into the electrolyte and connect them to the electrochemical workstation to form the final molecularly imprinted membrane electrochemical sensor.

[0013] In step A1, the template molecule solution is an adrenaline solution.

[0014] In step A3, the ratio of the intermediate to the template molecule solution is 1.1220-1.125 g: 1 mL, and the template molecule solution is a solution with an adrenaline concentration of 0.5-0.55 mmol / L.

[0015] In step S1, the hydroxylated multi-walled carbon nanotube dispersion is obtained by adding hydroxylated multi-walled carbon nanotubes to an aqueous solution of sodium dodecyl sulfate in a required proportion and then dispersing them by ultrasonication. The concentration of hydroxylated multi-walled carbon nanotubes in the dispersion is 4.5-5.5 mg / mL, and the concentration of sodium dodecyl sulfate in the aqueous solution is 1.43-1.47 mg / mL.

[0016] In step A2, the total solid content of the oligomeric silsesquioxane-Al2O3 composite sol and indium tin sol (ITO) is 0.95-1.05%, and the mass ratio of the oligomeric silsesquioxane-Al2O3 composite sol and indium tin sol (ITO) is 1:0.9-1.1.

[0017] In step A1, mixture A is added dropwise to mixture B at a rate of 2-3 drops per second. After the addition is complete, the temperature is raised to 50-55℃ and the reaction is carried out for 8-12 hours to obtain oligomeric silsesquioxane-Al2O3 composite sol. The amount of water, glacial acetic acid, Al2O3 sol, and anhydrous ethanol added in mixture A is 0.29-0.31 mol: 0.008-0.012 g: 0.58-0.62 g: 14.8-15.2 g. The amount of methyltrimethoxysilane and anhydrous ethanol mixed solution in mixture B is 0.048-0.052 mol: 38-42 g.

[0018] In step S1, the polishing process involves first polishing the glassy carbon electrode into a mirror surface, and then sequentially using ultrapure water, anhydrous ethanol, and ultrapure water for ultrasonic vibration.

[0019] A molecularly imprinted membrane electrochemical sensor is prepared by the aforementioned preparation method.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] This invention discloses a method for preparing a molecularly imprinted membrane electrochemical sensor. First, a glassy carbon electrode (OH-MWCNTs-GCE) modified with hydroxylated multi-walled carbon nanotubes (MIP) and a molecularly imprinted polymer (MIP) are prepared. Then, the MIP is drop-coated onto the surface of the OH-MWCNTs-GCE electrode. After high-temperature curing, a MIP-OH-MWCNTs-GCE electrode is obtained. Finally, the MIP-OH-MWCNTs-GCE electrode, along with a reference electrode and a working electrode, is inserted into an electrolyte and connected to an electrochemical workstation to form a molecularly imprinted membrane electrochemical sensor. In this design, because the surface of the hydroxylated multi-walled carbon nanotubes has a large number of hydroxyl functional groups, it can form more hydrogen bonds with the MIP, resulting in a stronger bond between the MIP and the OH-MWCNTs-GCE electrode surface. The amplification of electrical signals enhances sensor sensitivity. Furthermore, the oligomeric silsesquioxane-Al2O3 composite sol, being a network polymer, provides more imprinting sites for template molecules, resulting in more specific cavities and extremely low detection limits, significantly improving sensitivity. The oligomeric silsesquioxane-Al2O3 composite sol exhibits excellent dry and wet adhesion to the hydroxylated multi-walled carbon nanotube-modified glassy carbon electrode (OH-MWCNTs-GCE), preventing detachment and contributing to excellent repeatability and stability of the sensor. When the oligomeric silsesquioxane-Al2O3 composite sol is combined with indium tin sol (ITO), the silica particles in both the ITO and ITO sols are similar in size and spherical, resulting in a large specific surface area, further providing more imprinting sites. Additionally, ITO sol enhances the conductivity of the molecularly imprinted polymer (MIP). Therefore, the molecularly imprinted electrochemical sensor prepared by this invention has an extremely low detection limit, higher detection sensitivity, larger sensing area, and better conductivity, which can better meet the detection requirements. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the synthesis of the MIP-OH-MWCNTs-GCE electrode in this invention.

[0023] Figure 2 This is a schematic diagram of the oligomeric silsesquioxane-Al2O3 composite sol structure imprinted with adrenaline in this invention.

[0024] Figure 3 This is a schematic diagram of the oligomeric silsesquioxane-Al2O3 composite sol structure after adrenaline elution in this invention.

[0025] Figure 4 The peak current values ​​of the response of the molecularly imprinted membrane electrochemical sensor are shown for different elution times.

[0026] Figure 5 DPV diagrams of molecularly imprinted membrane electrochemical sensors at different elution times.

[0027] Figure 6 The peak current values ​​of the response of the molecularly imprinted membrane electrochemical sensor are shown for different imprinting times.

[0028] Figure 7 DPV diagrams of molecularly imprinted membrane electrochemical sensors with different imprinting times.

[0029] Figure 8 The peak current value of the response of the molecularly imprinted membrane electrochemical sensor is given in the presence of interfering molecules.

[0030] Figure 9 The peak current values ​​of the response of the molecularly imprinted membrane electrochemical sensor are given after culturing in five groups of culture media with the same adrenaline concentration.

[0031] Figure 10 The peak current values ​​of the response of the molecularly imprinted membrane electrochemical sensor were determined after culturing in culture media with different adrenaline concentrations.

[0032] Figure 11 To obtain a linear relationship between the peak current value of the molecularly imprinted membrane electrochemical sensor response and the adrenaline concentration.

[0033] Figure 12 The peak current of the response during the elution process of test example 1.

[0034] Figure 13 The peak current of the response during the imprinting process of test example 1.

[0035] Figure 14 The peak current of the response during the elution process of test example 2.

[0036] Figure 15 The peak current of the response during the imprinting process is used to test Example 2.

[0037] Figure 3 In the case of oligomeric silsesquioxane-Al2O3 composite sol, the cavity inside is the specific cavity left after the template molecule adrenaline is eluted. Detailed Implementation

[0038] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings.

[0039] Example 1:

[0040] See Figures 1 to 3 A method for preparing a molecularly imprinted membrane electrochemical sensor, comprising the following steps:

[0041] S1. Prepare a glassy carbon electrode (OH-MWCNTs-GCE) modified with hydroxylated multi-walled carbon nanotubes according to the following steps:

[0042] S11. Hydroxylated multi-walled carbon nanotubes are added to an aqueous solution of sodium dodecyl sulfate in the required proportion and ultrasonically dispersed for 40 min to obtain a dispersion of hydroxylated multi-walled carbon nanotubes. The concentration of hydroxylated multi-walled carbon nanotubes in the dispersion is 5 mg / mL, and the parameters of the hydroxylated multi-walled carbon nanotubes are: length 10-30 μm, outer diameter 10-20 nm, inner diameter 5-10 nm, purity >95%, and hydroxyl content 3.06 wt%. The concentration of sodium dodecyl sulfate in the aqueous solution is 5 mmol / L.

[0043] S12. 10 μL of hydroxylated multi-walled carbon nanotube dispersion was drop-coated onto the polished glassy carbon electrode. The electrode was first placed in air for 6 h and then placed in an oven at 60 °C for 5 h to obtain the hydroxylated multi-walled carbon nanotube modified glassy carbon electrode OH-MWCNTs-GCE. The polishing was performed by first polishing the glassy carbon electrode to a mirror surface with 0.05 μm α-Al2O3 on an electrode polishing instrument, and then ultrasonically vibrating it sequentially with ultrapure water, anhydrous ethanol and ultrapure water.

[0044] S2. Prepare molecularly imprinted polymers (MIPs) according to the following steps:

[0045] S21. Add mixture A dropwise to mixture B at a rate of 2-3 drops per second. After the addition is complete, raise the temperature to 52°C and react at 52°C for 10 hours to obtain the following result: Figure 3 The oligomeric silsesquioxane-Al2O3 composite sol shown is provided in the following: Mixture A is obtained by ultrasonic dispersion of 0.3 mol distilled water, 0.01 g glacial acetic acid, 0.6 g Al2O3 sol, and 15 g anhydrous ethanol; Mixture B is obtained by magnetic stirring for 30 min of 0.05 mol methyltrimethoxysilane and 40 g anhydrous ethanol; and the Al2O3 sol refers to nano-alumina water-based transparent sol, model VK-L10A.

[0046] S22. Weigh 37 μL of oligomeric silsesquioxane-Al2O3 composite sol and 7.6 μL of indium tin sol (ITO) at a mass ratio of 1:1. Calculate the required amount of anhydrous ethanol to be 1.38 mL based on a total solid content of 1% for the oligomeric silsesquioxane-Al2O3 composite sol and ITO. Mix the above components and stir at room temperature for 4 hours until the texture is uniform and transparent, resulting in a deep blue intermediate. The ITO model used is ITO-WP030.

[0047] S23. Mix 1.122g of intermediate with 1mL of template molecule solution to prepare molecularly imprinted polymer (MIP), wherein the template molecule solution is adrenaline with a concentration of 0.5mmol / L.

[0048] S3. 7 μL of molecularly imprinted polymer MIP was drop-coated onto the surface of glassy carbon electrode OH-MWCNTs-GCE modified with hydroxylated multi-walled carbon nanotubes. The electrode was placed at room temperature in the dark for 12 h, and then placed in an oven at 60 °C for 2 h to obtain the MIP-OH-MWCNTs-GCE electrode.

[0049] S4. Insert the MIP-OH-MWCNTs-GCE electrode together with the reference electrode and the working electrode into the electrolyte and connect them to the electrochemical workstation to form a molecularly imprinted membrane electrochemical sensor. The reference electrode and the working electrode are respectively selected as calomel electrode and platinum electrode.

[0050] 1. Determine the optimal elution time and optimal imprinting time.

[0051] Step 1: The molecularly imprinted membrane electrochemical sensor was placed in a 1 mol / L hydrochloric acid aqueous solution to elute the template molecule adrenaline. Differential pulse voltammetry (DPV) was used to measure the eluent during the elution process. The parameters of the DPV were set as follows: scan potential range of 0.0 V to 0.4 V, pulse amplitude of 50 mV, pulse width of 50 ms, potential increment of 4 mV, and pulse period of 500 ms. The peak current change graph and DPV graph of the elution process are shown below. Figure 4 , Figure 5 As shown;

[0052] Depend on Figure 4 It can be seen that when using a 1 mol / L hydrochloric acid aqueous solution as the eluent, there is a clear absorption peak of adrenaline molecules at a potential of 0.156 V. As the elution time gradually increases, this absorption peak becomes weaker and weaker, eventually almost disappearing, indicating that the template molecules have been completely eluted. Figure 5 It can be seen that the response peak current decreases rapidly with the increase of elution time. After 5 minutes, the response peak current does not change significantly and remains basically stable. Therefore, 5 minutes is selected as the optimal elution time.

[0053] Step 2: The eluted molecularly imprinted membrane electrochemical sensor is inserted into a culture medium containing imprinted template molecules. The culture medium is a PBS buffer solution with an adrenaline concentration of 40 mmol / L and a pH of 7. The DPV method is used to measure the imprinting process, and the peak current change graph and DPV graph are shown below. Figure 6 , Figure 7 As shown;

[0054] Depend on Figure 6It can be seen that the adrenaline absorption peak becomes stronger with increasing imprinting time, indicating that the template molecules are re-imprinted onto the electrochemical sensor; Figure 7 It can be seen that the peak current value of the response increases rapidly with the increase of the imprinting time. After reaching 20 minutes, the peak current value of the response does not change significantly and remains basically stable. Therefore, 20 minutes is selected as the optimal imprinting time.

[0055] 2. Selectivity for the template molecule adrenaline

[0056] Using a culture medium concentration of 5 μmol / L as a baseline, four other interfering molecules were added to the culture medium in molar proportions: procaine hydrochloride, isoproterenol hydrochloride, dopamine hydrochloride, torasemide, and terbutaline. The adrenaline response peak current of the molecularly imprinted membrane electrochemical sensor prepared according to this invention in the presence of interfering molecules was measured using the DPV method. The test results are as follows: Figure 8 As shown;

[0057] Depend on Figure 8 It can be seen that, compared to the presence of adrenaline only in the culture medium ( Figure 8 -a), found a 60-fold concentration of isoproterenol hydrochloride ( Figure 8 -b), 50 times the concentration of dopamine hydrochloride ( Figure 8 -c), 100 times the concentration of torasemide ( Figure 8 -d), 100 times the concentration of terbutaline ( Figure 8 -e) hardly caused any change in the peak current value of adrenaline, with only a 3.4-5.0% change in the response peak current value. This shows that the molecularly imprinted membrane electrochemical sensor constructed in this invention still has good selectivity for adrenaline in the presence of interfering molecules.

[0058] 3. Reproducibility and stability

[0059] (1) The response peak current value of the molecularly imprinted membrane electrochemical sensor prepared in this invention was tested by the DPV method after culturing in five culture media with the same adrenaline concentration of 40 mmol / L. The test results are as follows: Figure 9 As shown;

[0060] Depend on Figure 9 It can be seen that the five test results all have similar adrenaline peak current signals, with an RSD value of 4.6%, indicating that the molecularly imprinted membrane electrochemical sensor prepared in this invention has good reproducibility.

[0061] (2) The molecularly imprinted membrane electrochemical sensor prepared in this invention was first stored at 2°C for 15 days, and then its response peak current value after culturing in the culture medium was tested by the DPV method. The adrenaline concentration in the culture medium was 40 mmol / L. The test showed that after 15 days of storage, the response peak current value of the molecularly imprinted membrane electrochemical sensor still had 96.2% of the initial response peak current value, which can prove the high stability of the molecularly imprinted membrane electrochemical sensor constructed in this invention.

[0062] 4. Detection limit

[0063] The response peak current values ​​of the molecularly imprinted membrane electrochemical sensor prepared in this invention were obtained by DPV method after culturing in culture media with different concentrations of adrenaline. The tests showed a good linear relationship between the response peak current value and the adrenaline concentration in the range of 0.0014-2.12 μmol / L, with a linear regression equation of I(μA) = 6.629C + 1.527(μmol / L) (R = 99.90%). In the linear regression equation, C represents the detection limit, and the final calculated detection limit C is 4.656 × 10⁻⁶. -11 The molecularly imprinted membrane electrochemical sensor constructed in this invention has an extremely low detection limit, as indicated by the concentration of adrenaline (mol / L). The peak response current values ​​after culturing in a medium with adrenaline concentrations of 0.0014-2.12 μmol / L are shown below. Figure 10 As shown in the figure, the linear relationship between the peak current value of the molecularly imprinted membrane electrochemical sensor response and the adrenaline concentration was obtained by fitting, as follows: Figure 11 As shown.

[0064] 5. Horse serum sample experiment

[0065] Horse serum sample acquisition: Centrifuge 5 mL of horse serum at 3000 rpm for 5 min, and dilute the supernatant 100 times.

[0066] The epinephrine concentrations in the three horse serum samples were 0.1 μmol / L, 0.05 μmol / L, and 0.01 μmol / L, respectively, and were determined by spiked recovery. The concentrations of epinephrine in the three horse serum samples were detected using a molecularly imprinted membrane electrochemical sensor, and the response peak current values ​​were recorded. The detection results are shown in Table 1.

[0067] Table 1. Detection results of three horse serum samples

[0068]

[0069] As shown in Table 1, the recovery rate was 94.97%-98.96% and the RSD value was 1.8%-4.4%, which indicates that the constructed molecularly imprinted membrane electrochemical sensor has high detection accuracy for adrenaline in horse blood and has good practical application value.

[0070] 6. Peak current signal comparison

[0071] A molecularly imprinted membrane electrochemical sensor prepared by an aminated multi-walled carbon nanotube-modified glassy carbon electrode (preparation process same as in Example 1) and a molecularly imprinted membrane electrochemical sensor prepared by a carboxylated multi-walled carbon nanotube-modified glassy carbon electrode (preparation process same as in Example 1) were used as Test Example 1 and Test Example 2, respectively, for comparison with the molecularly imprinted membrane electrochemical sensor prepared in this invention. The response peak currents of Test Example 1 and Test Example 2 during the elution and imprinting processes in a culture medium with an adrenaline concentration of 40 mmol / L were detected using the DPV method. The response peak currents of Test Example 1 during the elution and imprinting processes are shown below. Figure 12 , 13 As shown, the response peak currents of Test Example 2 during the elution and blotting processes are respectively as follows: Figure 14 , 15 As shown;

[0072] Depend on Figures 12-15 It can be seen that in Test Example 2, the peak current signal almost disappeared during both the elution and imprinting processes; in Test Example 1, the peak current signal was relatively obvious during the elution and imprinting processes, but the peak current intensity was weaker than that of the molecularly imprinted membrane electrochemical sensor prepared in this invention, and the characteristic potential of the template molecule adrenaline was not obvious, and the current signal was not stable enough. The speculation is that, since the carboxyl groups on the surface of carboxyl multi-walled carbon nanotubes are highly active, they participate in the reaction during the preparation of the imprinted polymer, which leads to changes in the structure of the carbon nanotubes, resulting in a decrease in their conductivity, thus making it impossible for the sensor to detect the electrical signal of the template molecule adrenaline; and the amino groups of amino multi-walled carbon nanotubes gradually react with acids to form ammonium ions during the preparation of the imprinted polymer, which also affects the structure of the carbon nanotubes, leading to a decrease in their conductivity, so the electrical signal of the imprinted template molecule adrenaline gradually weakens.

Claims

1. A method for preparing a molecularly imprinted membrane electrochemical sensor, characterized in that: The preparation method includes the following steps: S1. Preparation of hydroxylated multi-walled carbon nanotube-modified glassy carbon electrode OH-MWCNTs-GCE and molecularly imprinted polymer MIP, wherein the hydroxylated multi-walled carbon nanotube-modified glassy carbon electrode OH-MWCNTs-GCE is obtained by drop-coating a dispersion of hydroxylated multi-walled carbon nanotubes onto a polished glassy carbon electrode and then curing it at high temperature; the preparation steps of the molecularly imprinted polymer MIP include: A1. Add mixture A dropwise to mixture B to react and obtain oligomeric silsesquioxane-Al2O3 composite sol. Mixture A is a mixed solution obtained by mixing water, glacial acetic acid, Al2O3 sol and anhydrous ethanol in the required proportion. Mixture B is an oligomeric silsesquioxane solution obtained by mixing methyltrimethoxysilane and anhydrous ethanol in the required proportion. A2. Mix oligomeric silsesquioxane-Al2O3 composite sol, indium tin sol (ITO), and anhydrous ethanol in the required proportions and react to obtain an intermediate. A3. The intermediate is mixed with the template molecule solution to obtain the molecularly imprinted polymer (MIP). S2. Molecularly imprinted polymer (MIP) is drop-coated onto the surface of glassy carbon electrode OH-MWCNTs-GCE modified with hydroxylated multi-walled carbon nanotubes, and then subjected to high-temperature curing to obtain MIP-OH-MWCNTs-GCE electrode. S3. Insert the MIP-OH-MWCNTs-GCE electrode, along with the reference electrode and the working electrode, into the electrolyte and connect them to the electrochemical workstation to form the final molecularly imprinted membrane electrochemical sensor.

2. The method for preparing a molecularly imprinted membrane electrochemical sensor according to claim 1, characterized in that: In step A1, the template molecule solution is an adrenaline solution.

3. The method for preparing a molecularly imprinted membrane electrochemical sensor according to claim 2, characterized in that: In step A3, the ratio of the intermediate to the template molecule solution is 1.121-1.123 g: 1 mL, and the adrenaline concentration in the template molecule solution is 0.45-0.55 mmol / L.

4. A method for preparing a molecularly imprinted membrane electrochemical sensor according to any one of claims 1-3, characterized in that: In step S1, the hydroxylated multi-walled carbon nanotube dispersion is obtained by adding hydroxylated multi-walled carbon nanotubes to an aqueous solution of sodium dodecyl sulfate in a required proportion and then dispersing them by ultrasonication. The concentration of hydroxylated multi-walled carbon nanotubes in the dispersion is 4.5-5.5 mg / mL, and the concentration of sodium dodecyl sulfate in the aqueous solution is 1.43-1.47 mg / mL.

5. A method for preparing a molecularly imprinted membrane electrochemical sensor according to any one of claims 1-3, characterized in that: In step A2, the total solid content of the oligomeric silsesquioxane-Al2O3 composite sol and indium tin sol (ITO) is 0.95-1.05%, and the mass ratio of the oligomeric silsesquioxane-Al2O3 composite sol and indium tin sol (ITO) is 1:0.9-1.

1.

6. A method for preparing a molecularly imprinted membrane electrochemical sensor according to any one of claims 1-3, characterized in that: In step A1, mixture A is added dropwise to mixture B at a rate of 2-3 drops per second. After the addition is complete, the temperature is raised to 50-55℃ and the reaction is carried out for 8-12 hours to obtain oligomeric silsesquioxane-Al2O3 composite sol. The amount of water, glacial acetic acid, Al2O3 sol, and anhydrous ethanol added in mixture A is 0.29-0.31 mol: 0.008-0.012 g: 0.58-0.62 g: 14.8-15.2 g. The amount of methyltrimethoxysilane and anhydrous ethanol mixed solution in mixture B is 0.048-0.052 mol: 38-42 g.

7. A method for preparing a molecularly imprinted membrane electrochemical sensor according to any one of claims 1-3, characterized in that: In step S1, the polishing process involves first polishing the glassy carbon electrode into a mirror surface, and then sequentially using ultrapure water, anhydrous ethanol, and ultrapure water for ultrasonic vibration.

8. A molecularly imprinted membrane electrochemical sensor, characterized in that: The molecularly imprinted membrane electrochemical sensor is prepared by any one of the preparation methods in claims 1-7.

Images