CNT / Cu / C / MIP / GCE molecularly imprinted electrochemical sensor, construction method and application thereof

Abstract

The present invention discloses a CNT / Cu / C / MIP / GCE molecularly imprinted electrochemical sensor, a construction method, and applications thereof. The present invention combines molecular imprinting technology with electrochemical sensing technology. The CNT / Cu / C / MIP / GCE molecularly imprinted electrochemical sensor is constructed by layer-by-layer modification of the surface of a glassy carbon electrode with a high-temperature calcination product of carbon nanotubes and a copper-tricarboxylic acid metal-organic framework composite material (CNT / Cu-BTC MOF). The CNT / Cu / C / MIP / GCE molecularly imprinted electrochemical sensor is simple to construct and exhibits high sensitivity, selectivity, reproducibility, and stability. It can be used to detect 4,4'-diaminodiphenyl ether in plastic packaging materials in batches.

Description

Technical Field

[0001] The present invention belongs to the field of electrochemical sensing, and in particular relates to a CNT / Cu / C / MIP / GCE molecular imprinting electrochemical sensor, a construction method and applications thereof. Background Art

[0002] Food safety concerns extend beyond the food itself, as well as packaging materials that come into close contact with food. Harmful substances in these materials can migrate into food, posing a threat to human health. Among food contact materials, 4,4'-diaminodiphenyl ether (DDO) is a harmful aromatic amine that is known to cause mutations, teratogenesis, and carcinogenesis. Therefore, developing a rapid and efficient detection method for DDO is crucial.

[0003] Currently, quantitative detection of aromatic amines is commonly performed using methods such as liquid chromatography, gas chromatography, and liquid chromatography-mass spectrometry. These methods require expensive instruments, require time-consuming sample preparation, and are difficult to achieve rapid detection. Summary of the Invention

[0004] In response to the shortcomings of the existing technology, the present invention provides a CNT / Cu / C / MIP / GCE molecularly imprinted electrochemical sensor, a construction method and its application. The specific technical solutions are as follows:

[0005] A method for constructing a CNT / Cu / C / MIP / GCE molecularly imprinted electrochemical sensor comprises the following steps:

[0006] Step 1: dissolving copper nitrate trihydrate and polyvinyl pyrrolidone in methanol and ultrasonically homogenizing to obtain a blue solution; adding a methanol solution containing trimesic acid to the blue solution to obtain a mixed solution; in the mixed solution, the molar concentration ratio of the copper nitrate and trimesic acid is 2:1; adding carbon nanotubes to the mixed solution under stirring, and continuing to stir until the carbon nanotubes are uniformly dispersed in the mixed solution, and then further aging at room temperature, centrifuging and collecting the obtained blue precipitate, then washing it thoroughly with methanol and ethanol, and vacuum drying to obtain a CNT / Cu-BTC MOF composite material;

[0007] Step 2: calcining the CNT / Cu-BTC MOF composite material in an inert gas atmosphere to obtain an electrochemical sensor material CNT / Cu / C;

[0008] Step 3: ultrasonically clean the ground and polished glassy carbon electrode to remove impurities on the electrode surface, then dry it, and place the dried glassy carbon electrode in H2SO4 for electrochemical activation to obtain a pretreated glassy carbon electrode; ultrasonically disperse the electrochemical sensor material CNT / Cu / C in a mixed solution of water, ethanol, and Nafion in a volume ratio of 12:12:1 to obtain solution A, in which the concentration of the electrode modification material CNT / Cu / C in solution A is 5 mg / ml; dropwise apply the solution A on the surface of the pretreated glassy carbon electrode and naturally dry it at room temperature to obtain CNT / Cu / C / GCE;

[0009] Step 4: dissolving 4,4'-diaminodiphenyl ether, acrylamide and methacrylic acid in a mixed solvent of dimethyl sulfoxide and acetonitrile to obtain a reaction solution, wherein the molar concentration ratio of 4,4'-diaminodiphenyl ether, acrylamide and methacrylic acid in the reaction solution is 1:3:3; adding azobisisobutyronitrile as an initiator and ethylene glycol dimethacrylate as a cross-linking agent to the reaction solution, under an inert atmosphere, at a temperature of not less than 65 ℃, and stirring the reaction to obtain a MIP suspension after complete thermal polymerization; the MIP suspension is centrifuged, washed with water and ethanol, and dried to obtain an uneluted MIP powder; finally, eluted with an eluent to obtain a molecularly imprinted polymer MIP; the molecularly imprinted polymer MIP is ultrasonically dispersed in water to obtain a solution B, wherein the concentration of the molecularly imprinted polymer MIP in solution B is 5 mg / ml; solution B is drop-coated on the surface of the CNT / Cu / C / MIP / GCE obtained in step 3, and after natural drying at room temperature, a CNT / Cu / C / MIP / GCE molecularly imprinted electrochemical sensor is obtained.

[0010] Furthermore, in the step 1, after adding carbon nanotubes to the mixed solution, stirring is continued for 10-30 minutes.

[0011] Furthermore, in step 4, the amounts of azobisisobutyronitrile (initiator) and ethylene glycol dimethacrylate (crosslinking agent) added to the reaction solution should ensure that the thermal polymerization reaction is complete.

[0012] Furthermore, the time for further complete aging at room temperature is 24-48 hours.

[0013] Furthermore, in the step 2, the heating rate of calcination is 5-20°C / min, the temperature is raised to 800°C and calcined at a constant temperature for 2 hours, and then taken out after cooling to room temperature.

[0014] A CNT / Cu / C / MIP / GCE molecular imprinting electrochemical sensor constructed by the above construction method.

[0015] Application of a CNT / Cu / C / MIP / GCE molecularly imprinted electrochemical sensor in the detection of 4,4'-diaminodiphenyl ether.

[0016] The beneficial effects of the present invention are as follows:

[0017] (1) The CNT / Cu / C composite material prepared in the present invention increases the effective surface area and electron transfer capacity of the electrode, thereby improving the current response and enriching the application of metal organic framework material derivatives in electrochemical sensing.

[0018] (2) The present invention combines molecular imprinting technology with electrochemical sensing technology. The prepared molecular imprinting electrochemical sensor can specifically recognize 4,4'-ODA and has good selectivity for 4,4'-ODA.

[0019] (3) The CNT / Cu / C / MIP / GCE molecular imprinting electrochemical sensor provided by the present invention can be used to quantitatively detect the content of 4,4'-ODA in actual samples.

[0020] (4) The CNT / Cu / C / MIP / GCE molecularly imprinted electrochemical sensor provided by the present invention innovatively uses a CNT / Cu-BTC high-temperature calcined product and a molecularly imprinted polymer composite material to construct an electrochemical sensor. This fully utilizes the advantages of the metal-organic framework material's high specific surface area, porosity, and multiple active sites, the high electron transfer ability of CNT, and the excellent specific recognition and high selectivity of the molecularly imprinted polymer. The synergistic effect of the three effectively improves the detection sensitivity, selectivity, and stability of the electrochemical sensor. The sensor is simple to construct and has high sensitivity, high selectivity, high reproducibility, and high stability. It can be used to detect 4,4'-diaminodiphenyl ether in plastic packaging materials in batches. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is the X-ray diffraction pattern of CNT / Cu / C in Example 2 of the present invention.

[0022] Figure 2 This is the SEM spectrum of CNT / Cu / C in Example 2 of the present invention.

[0023] Figure 3 This is the XPS photoelectric spectrum of CNT / Cu / C in Example 2 of the present invention

[0024] Figure 4 CV graphs of different electrochemical sensor materials in potassium ferricyanide solution according to an embodiment of the present invention.

[0025] Figure 51 is a DPV graph of the CNT / Cu / C / MIP / GCE molecularly imprinted electrochemical sensor detecting different concentrations of 4,4'-ODA in a solution and a linear relationship graph between the DPV peak current and the concentration in an embodiment of the present invention. DETAILED DESCRIPTION

[0026] The present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments, and the purpose and effects of the present invention will become more apparent. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0027] Example 1

[0028] Step 1: Preparation of CNT / Cu-BTC MOF composites

[0029] 0.5 mmol of Cu(NO₃)₂·3H₂O and 0.4 g of polyvinylpyrrolidone (PVP) were dissolved in 50 mL of methanol and homogenized by sonication to obtain a blue solution. Then, 50 mL of a methanol solution containing 0.25 mmol of trimesic acid (BTC) was added to the blue solution to obtain a mixed solution. 0.05 g of carbon nanotubes (CNTs) was added while stirring. Stirring was continued for 10 minutes to uniformly disperse the CNTs in the mixed solution. The mixed solution was further aged at room temperature for 24 hours. The resulting blue precipitate was collected by centrifugation, washed several times with methanol and ethanol, and dried under vacuum to obtain a CNT / Cu-BTC MOF composite.

[0030] Step 2: Preparation of electrochemical sensor material CNT / Cu / C

[0031] Place 100 mg of the CNT / Cu-BTC MOF composite synthesized in Step 1 in a porcelain boat, place it in a tube furnace, and calcine it under a nitrogen atmosphere. Ramp the temperature to 800°C at a rate of 5°C / min and calcine for 2 hours. Cool to room temperature and remove from the oven to obtain the electrochemical sensor material, CNT / Cu / C.

[0032] Step 3: Preparation of CNT / Cu / C / GCE electrode

[0033] (1) Pretreatment of glassy carbon electrode: polish the glassy carbon electrode with 50 nm alumina powder on a deerskin polishing cloth, and rinse the residual alumina powder on the electrode with pure water; ultrasonically clean the electrode in anhydrous ethanol and ultrapure water for three minutes to remove impurities on the electrode surface, then dry it, and place the dried glassy carbon electrode in 0.5 mol / L sulfuric acid solution and perform cyclic voltammetry scanning in the voltage range of -1~1V until the scanning curve stabilizes;

[0034] (2) Drop coating of CNT-1 / Cu / C catalyst: 5 mg of the electrochemical sensor material CNT / Cu / C was added to a mixed solution containing 480 μL of pure water, 480 μL of anhydrous ethanol, and 40 μL of Nafion. Ultrasonication was performed for more than 30 min to obtain a uniform solution. 6 μL of this solution was added dropwise to the glassy carbon electrode three times, dried to form a film, and the catalyst drop coating was completed to obtain CNT / Cu / C / GCE.

[0035] Step 4: Construction of CNT / Cu / C / MIP / GCE molecularly imprinted electrochemical sensor:

[0036] (1) Preparation of molecularly imprinted polymer (MIP):

[0037] 5 mM 4,4′-diaminodiphenyl ether, 15 mM acrylamide, and 15 mM methacrylic acid were sonicated in 120 mL of a mixed solution (20 mL dimethyl sulfoxide, 100 mL acetonitrile) to obtain Solution A. To 50 mL of Solution A, 0.05 g of azobisisobutyronitrile and 1 mL of ethylene glycol dimethacrylate were added. After sonication for 1 h, nitrogen was introduced for 30 minutes to remove dissolved oxygen, resulting in Solution B. Solution B was vigorously stirred at 65°C for 6 h to obtain a MIP suspension containing 4,4′-diaminodiphenyl ether. The suspension was centrifuged, washed with water and ethanol, and dried to obtain an uneluted MIP powder. Finally, the powder was eluted with a methanol:acetic acid solution (8:2 v / v) and dried to obtain a template-free MIP powder.

[0038] (2) MIP drop coating: 1 mL of pure water was added to 5 mg of MIP powder and ultrasonicated for more than 30 min to obtain a homogeneous solution. 6 μL of this solution was added dropwise three times onto the CNT / Cu / C / GCE electrode prepared above and dried to form a film. This completed the MIP drop coating and thus obtained a CNT / Cu / C / MIP / GCE molecularly imprinted electrochemical sensor.

[0039] Example 2

[0040] Step 1: Preparation of CNT / Cu-BTC MOF composite material:

[0041] 0.5 mmol of Cu(NO₃)⋅3H₂O and 0.4 g of polyvinylpyrrolidone (PVP) were dissolved in 50 mL of methanol and homogenized by sonication to obtain a blue solution. Then, 50 mL of a methanol solution containing 0.25 mmol of trimesic acid (BTC) was added to the blue solution to obtain a mixed solution. 0.4 g of carbon nanotubes (CNTs) was added while stirring. Stirring was continued for 30 minutes to uniformly disperse the CNTs in the mixed solution. The mixed solution was further aged at room temperature for 48 hours. The resulting blue precipitate was collected by centrifugation, washed several times with methanol and ethanol, and dried under vacuum to obtain a CNT / Cu-BTC MOF composite.

[0042] Step 2: Preparation of electrochemical sensor material CNT / Cu / C

[0043] Place 100 mg of the CNT / Cu-BTC MOF composite synthesized in Step 1 in a porcelain boat, place it in a tube furnace, and calcine it under a nitrogen atmosphere. Ramp the temperature to 800°C at a rate of 20°C / min and calcine for 2 hours. Cool to room temperature and remove from the oven to obtain the electrochemical sensor material, CNT / Cu / C.

[0044] Step 3: Preparation of CNT / Cu / C / GCE electrode

[0045] (1) Pretreatment of glassy carbon electrode: polish the glassy carbon electrode with 50 nm alumina powder on a deerskin polishing cloth, and rinse the residual alumina powder on the electrode with pure water; ultrasonically clean the electrode in anhydrous ethanol and ultrapure water for three minutes to remove impurities on the electrode surface, then dry it, and place the dried glassy carbon electrode in 0.5 mol / L sulfuric acid solution and perform cyclic voltammetry scanning in the voltage range of -1~1V until the scanning curve stabilizes;

[0046] (2) Drop coating of CNT / Cu / C catalyst: 5 mg of the electrochemical sensor material CNT / Cu / C was added to a mixed solution containing 480 μL of pure water, 480 μL of anhydrous ethanol, and 40 μL of Nafion. Ultrasonication was performed for more than 30 min to obtain a uniform solution. 6 μL of this solution was added dropwise to the glassy carbon electrode three times, dried to form a film, and the catalyst drop coating was completed to obtain CNT / Cu / C / GCE.

[0047] Step 4: Construction of CNT / Cu / C / MIP / GCE molecularly imprinted electrochemical sensor:

[0048] (1) Preparation of molecular imprinting polymer (MIP): 5 mM 4,4′-diaminodiphenyl ether, 15 mM acrylamide and 15 mM methacrylic acid were ultrasonically dissolved in a mixed solution of 120 mL (20 mL dimethyl sulfoxide, 100 mL acetonitrile) to obtain solution A. 50 mL of the above solution A was taken, and 0.2 g of azobisisobutyronitrile and 5 mL of ethylene glycol dimethacrylate were added. After ultrasonication for 1 hour, nitrogen was introduced into the solution for 30 minutes to remove dissolved oxygen to obtain solution B. The obtained solution B was vigorously stirred at 80°C for 24 hours to obtain a MIP suspension containing 4,4′-diaminodiphenyl ether. The suspension was centrifuged, washed with water and ethanol, and dried to obtain an uneluted MIP powder. Finally, the powder was stirred and eluted with a solution of methanol:acetic acid = 8:2 (V / V) and dried to obtain a molecular imprinting polymer (MIP) powder without template molecules.

[0049] (2) MIP drop coating: 1 mL of pure water was added to 5 mg of MIP powder and ultrasonicated for more than 30 min to obtain a homogeneous solution. 6 μL of this solution was added dropwise three times onto the CNT / Cu / C / GCE electrode prepared above and dried to form a film. This completed the MIP drop coating and thus obtained a CNT / Cu / C / MIP / GCE molecularly imprinted electrochemical sensor.

[0050] Example 3

[0051] Step 1: Preparation of CNT / Cu-BTC MOF composite material:

[0052] 0.5 mmol of Cu(NO₃)₂·3H₂O and 0.4 g of polyvinylpyrrolidone (PVP) were dissolved in 50 mL of methanol and homogenized by sonication to obtain a blue solution. Then, 50 mL of a methanol solution containing 0.25 mmol of trimesic acid (BTC) was added to the blue solution to obtain a mixed solution. 0.1 g of carbon nanotubes (CNTs) was added while stirring. Stirring was continued for 20 minutes to uniformly disperse the CNTs in the mixed solution. The mixed solution was further aged at room temperature for 36 hours. The resulting blue precipitate was collected by centrifugation, washed several times with methanol and ethanol, and dried under vacuum to obtain a CNT / Cu-BTC MOF composite.

[0053] Step 2: Preparation of electrochemical sensor material CNT / Cu / C

[0054] Place 100 mg of the CNT / Cu-BTC MOF composite synthesized in Step 1 in a porcelain boat, place it in a tube furnace, and calcine it under a nitrogen atmosphere. Ramp the temperature to 800°C at a rate of 10°C / min and calcine for 2 hours. Cool to room temperature and remove from the oven to obtain the electrochemical sensor material, CNT / Cu / C. Figure 1 This is the X-ray diffraction pattern of CNT / Cu / C obtained in this example. It can be seen from the figure that after calcination, four obvious diffraction peaks appear in the XRD at 2θ = 26.6°, 43.3°, 50.4°, and 74.1°, which correspond to the (004) crystal plane of the hexahedral carbon material (JCPDS 26-1080) and the (111), (200) and (220) crystal planes of the face-centered cubic structure copper (JCPDS 04-0836). Figure 2 This is a scanning electron microscope image of CNT / Cu / C. From the image, we can see that the copper nanoparticles maintain the original octahedral structure, but the particle size is smaller. The copper nanoparticles grow on the tubular carbon nanotubes. Figure 3 This is the XPS spectrum of CNT / Cu / C obtained in this example, from which we can see the energy spectra of all three component elements, further proving that CNT / Cu / C was prepared.

[0055] Step 3: Preparation of CNT / Cu / C / GCE electrode

[0056] (1) Pretreatment of glassy carbon electrode: polish the glassy carbon electrode with 50 nm alumina powder on a deerskin polishing cloth, and rinse the residual alumina powder on the electrode with pure water; ultrasonically clean the electrode in anhydrous ethanol and ultrapure water for three minutes to remove impurities on the electrode surface, then dry it, and place the dried glassy carbon electrode in 0.5 mol / L sulfuric acid solution and perform cyclic voltammetry scanning in the voltage range of -1~1V until the scanning curve stabilizes;

[0057] (2) Drop coating of CNT / Cu / C catalyst: 5 mg of the electrochemical sensor material CNT / Cu / C was added to a mixed solution containing 480 μL of pure water, 480 μL of anhydrous ethanol, and 40 μL of Nafion. Ultrasonication was performed for more than 30 min to obtain a uniform solution. 6 μL of this solution was added dropwise to the glassy carbon electrode three times, dried to form a film, and the catalyst drop coating was completed to obtain CNT / Cu / C / GCE.

[0058] Step 4: Preparation of CNT / Cu / C / MIP / GCE molecularly imprinted electrochemical sensor

[0059] (1) Preparation of molecular imprinting polymer (MIP): 5 mM 4,4′-diaminodiphenyl ether, 15 mM acrylamide and 15 mM methacrylic acid were ultrasonically dissolved in a mixed solution of 120 mL (20 mL dimethyl sulfoxide, 100 mL acetonitrile) to obtain solution A. 50 mL of the above solution A was taken, and 0.1 g of azobisisobutyronitrile and 2 mL of ethylene glycol dimethacrylate were added. After ultrasonication for 1 hour, nitrogen was introduced into the solution for 30 minutes to remove dissolved oxygen to obtain solution B. The obtained solution B was vigorously stirred at 70°C for 10 hours to obtain a MIP suspension containing 4,4′-diaminodiphenyl ether. The suspension was centrifuged, washed with water and ethanol, and dried to obtain an uneluted MIP powder. Finally, the powder was stirred and eluted with a solution of methanol:acetic acid = 8:2 (V / V) and dried to obtain a molecular imprinting polymer (MIP) powder without template molecules.

[0060] (2) MIP drop coating: 1 mL of pure water was added to 5 mg of MIP powder and ultrasonicated for more than 30 min to obtain a homogeneous solution. 6 μL of this solution was added dropwise three times onto the CNT / Cu / C / GCE electrode prepared above and dried to form a film. This completed the MIP drop coating and thus obtained a CNT / Cu / C / MIP / GCE molecularly imprinted electrochemical sensor.

[0061] In order to verify the performance of the electrochemical sensors obtained in different embodiments, the electrochemical characteristics of different electrochemical sensor electrodes in 5mM potassium ferrocyanide solution were first explored using cyclic voltammetry (CV). Figure 4 As shown, Figure 4 Each curve represents the electrochemical performance of different electrochemical sensor electrodes, as shown in Table 1.

[0062] Table 1 Figure 4 The electrodes and current intensities corresponding to the curves

[0063]

[0064] from Figure 4 As can be seen from Table 1, the redox peak current of the glassy carbon electrode in Example 3, which was sequentially coated with 6 μL of 5 mg / mL CNT / Cu / C composite material and 6 μL of 5 mg / mL MIP, increased, about 10 times that of the bare glassy carbon bare GCE, indicating that the composite material CNT / Cu / C in the example increased the effective surface area and electron transfer capacity of the electrode, thereby improving the current response. Figure 4 It can also be proved that the concentration of CNT / Cu / C in the present invention is the best.

[0065] The CNT / Cu / C / MIP / GCE molecularly imprinted electrochemical sensor prepared in Example 3 was eluted in a methanol:acetic acid solution of 8:2 (V / V) for 30 minutes. Subsequently, the eluted CNT / Cu / C / MIP / GCE was placed in a 4,4'-ODA solution for adsorption and the redox peak current was measured. The redox peak current before adsorption was recorded as Ip0, and the redox peak current after adsorption was recorded as Ip. Ip (background current value subtracted) was obtained. A standard curve was established based on the relationship between Ip and 4,4'-ODA concentration, as shown in FIG. Figure 5 As shown. Figure 5 As can be seen from the graph, the electrochemical sensor curve shows good linearity in the concentration range of 0.15-100 μM.

[0066] The present invention further tested the selectivity and stability of the CNT / Cu / C / MIP / GCE molecularly imprinted electrochemical sensor obtained in Example 3. Differential pulse voltammetry (DPV) was used to examine the electrochemical properties of the CNT / Cu / C / MIP / GCE molecularly imprinted electrochemical sensor in the presence of 10 μM 4,4'-ODA and 100 μM of various interfering substances. As shown in Table 2, the oxidation peak current response intensity was comparable to that in the absence of interfering substances when 10 times the concentration of the interfering substances was added, demonstrating that the CNT / Cu / C / MIP / GCE molecularly imprinted electrochemical sensor exhibits excellent selectivity for detecting 4,4'-ODA.

[0067] Table 2 Current intensity of the CNT / Cu / C / MIP / GCE molecularly imprinted electrochemical sensor obtained in Example 3 in the presence of different interferents

[0068]

[0069] We also tested the stability of the CNT / Cu / C / MIP / GCE molecularly imprinted electrochemical sensor obtained in Example 3. Over 21 days of continuous testing, the oxidation peak current response values ​​decreased by 1.2% on the 7th day, 3.4% on the 14th day, and 5.6% on the 21st day, indicating that the CNT / Cu / C / MIP / GCE molecularly imprinted electrochemical sensor has excellent stability.

[0070] In addition, 4,4'-ODA spike recovery experiments were conducted on the treated nylon spatula at three concentrations (4, 6, and 10 μM). The results showed that the CNT / Cu / C / MIP / GCE molecularly imprinted electrochemical sensor prepared in Example 3 had a 4,4'-ODA recovery rate ranging from 86.3% to 103.5% in actual nylon spatula samples, with a relative standard deviation ranging from 0.51% to 3.99%. This demonstrates that the molecularly imprinted sensor constructed in this invention has good accuracy and can be used for detection in real samples.

[0071] Those skilled in the art will understand that the foregoing descriptions are merely preferred embodiments of the invention and are not intended to limit the invention. Although the invention has been described in detail with reference to the foregoing examples, those skilled in the art will still be able to modify the technical solutions described in the foregoing examples or substitute equivalents for some of the technical features therein. Any modifications, equivalent substitutions, etc. made within the spirit and principles of the invention shall be included within the scope of protection of the invention.

Claims

1. A method for constructing a CNT / Cu / C / MIP / GCE molecularly imprinted electrochemical sensor, characterized in that: The steps include: Step 1: dissolving copper nitrate trihydrate and polyvinyl pyrrolidone in methanol and ultrasonically homogenizing to obtain a blue solution; adding a methanol solution containing trimesic acid to the blue solution to obtain a mixed solution; in the mixed solution, the molar concentration ratio of the copper nitrate and trimesic acid is 2:1; adding carbon nanotubes to the mixed solution under stirring, and continuing to stir until the carbon nanotubes are uniformly dispersed in the mixed solution, and then further aging at room temperature, centrifuging and collecting the obtained blue precipitate, then washing it thoroughly with methanol and ethanol, and vacuum drying to obtain a CNT / Cu-BTC MOF composite material; Step 2: calcining the CNT / Cu-BTC MOF composite material in an inert gas atmosphere to obtain an electrochemical sensor material CNT / Cu / C; the calcination temperature is increased at a rate of 5-20°C / min, the temperature is increased to 800°C and calcined at a constant temperature for 2 hours, and then taken out after cooling to room temperature; Step 3: ultrasonically clean the ground and polished glassy carbon electrode to remove impurities on the electrode surface, then dry it, and place the dried glassy carbon electrode in H2SO4 for electrochemical activation to obtain a pretreated glassy carbon electrode; ultrasonically disperse the electrochemical sensor material CNT / Cu / C in a mixed solution of water, ethanol, and Nafion in a volume ratio of 12:12:1 to obtain solution A, in which the concentration of the electrode modification material CNT / Cu / C in solution A is 5 mg / ml; dropwise apply the solution A on the surface of the pretreated glassy carbon electrode and naturally dry it at room temperature to obtain CNT / Cu / C / GCE; Step 4: dissolving 4,4'-diaminodiphenyl ether, acrylamide and methacrylic acid in a mixed solvent of dimethyl sulfoxide and acetonitrile to obtain a reaction solution, wherein the molar concentration ratio of 4,4'-diaminodiphenyl ether, acrylamide and methacrylic acid in the reaction solution is 1:3:3; adding azobisisobutyronitrile as an initiator and ethylene glycol dimethacrylate as a cross-linking agent to the reaction solution, under an inert atmosphere, at a temperature of not less than 65 ℃, and stirring the reaction to obtain a MIP suspension after complete thermal polymerization; the MIP suspension is centrifuged, washed with water and ethanol, and dried to obtain an uneluted MIP powder; finally, eluted with an eluent to obtain a molecularly imprinted polymer MIP; the molecularly imprinted polymer MIP is ultrasonically dispersed in water to obtain a solution B, wherein the concentration of the molecularly imprinted polymer MIP in solution B is 5 mg / ml; solution B is drop-coated on the surface of the CNT / Cu / C / MIP / GCE obtained in step 3, and after natural drying at room temperature, a CNT / Cu / C / MIP / GCE molecularly imprinted electrochemical sensor is obtained.

2. The method for constructing a CNT / Cu / C / MIP / GCE molecularly imprinted electrochemical sensor according to claim 1, characterized in that: In the step 1, after adding carbon nanotubes to the mixed solution, stirring is continued for 10-30 minutes.

3. The method for constructing a CNT / Cu / C / MIP / GCE molecularly imprinted electrochemical sensor according to claim 1, characterized in that: In the fourth step, the amounts of azobisisobutyronitrile (initiator) and ethylene glycol dimethacrylate (crosslinking agent) added to the reaction solution should ensure that the thermal polymerization reaction is complete.

4. The method for constructing a CNT / Cu / C / MIP / GCE molecularly imprinted electrochemical sensor according to claim 1, characterized in that: The further full aging time at room temperature is 24-48 hours.

5. A CNT / Cu / C / MIP / GCE molecularly imprinted electrochemical sensor constructed by the construction method according to any one of claims 1 to 4. 6 . Use of the CNT / Cu / C / MIP / GCE molecularly imprinted electrochemical sensor according to claim 5 in the detection of 4,4'-diaminodiphenyl ether.

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