Dual-signal molecularly imprinted sensor, preparation method thereof and application of dual-signal molecularly imprinted sensor in GenX detection

Abstract

The invention provides a dual-signal molecularly imprinted sensor, a preparation method thereof and application of the dual-signal molecularly imprinted sensor in GenX detection. The dual-signal molecularly imprinted sensor comprises a basic electrode, and gold nanoparticles, a Joule thermal carbon material layer, a thionine built-in probe and an MIP film which are sequentially arranged on the surface of the basic electrode, wherein the MIP film comprises a polymer monomer without GenX template molecules. The ECB / AuNPs coating is beneficial to enhancing volt-ampere response, and the optimal arrangement of the MIP layer provides higher peak change. The prepared electrochemical sensor is used for detecting GenX in water, and has the advantages of high specificity, strong stability and good anti-interference capability.

Description

Technical Field

[0001] The present invention relates to the technical field of electrochemical sensing, and in particular to a method for preparing a molecular imprinting sensor and application of the sensor in detecting hexafluoropropylene ether diacid (GenX) in groundwater. Background Art

[0002] Hexafluoropropylene ether diacid (GenX) is a precursor molecule used to manufacture chemical-resistant and non-stick products. Due to its persistence and bioaccumulation in water and soil, it poses a serious threat to human health and the ecological environment. Related reports have shown that the toxicity of GenX is higher than that of common long-chain perfluorinated compounds. In order to identify the source of pollution, rapid detection of GenX is required. Commonly used methods such as chromatography and mass spectrometry are very expensive to detect and quantify GenX, and are difficult to deploy as a means of continuous monitoring. In contrast, electrochemical sensors have the advantages of miniaturization, low price and high sensitivity. Electrochemical molecular imprinting sensors, as a model of molecular imprinting technology, are specially designed to accurately identify specific target molecules. Its working principle is to achieve efficient and specific capture of target molecules by accurately constructing imprinting cavities that match the shape, size and functional groups of the target molecules. This sensor not only shows excellent selectivity and affinity, but also has excellent stability and a simple preparation process, providing strong technical support for various detection applications.

[0003] However, the electrochemical sensors based on molecular imprinting technology to identify GenX still face some challenges in the preparation process. Low concentrations of GenX can pose a threat to the ecological environment. The current molecular imprinting sensors have a lot of room for improvement in sensitivity. In addition, in complex environmental samples, there are a large number of compounds with similar structures to GenX. These compounds may interfere with the detection of GenX and reduce the sensitivity and accuracy of the sensor. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a dual-signal molecular imprinting sensor, a preparation method thereof and its application in detecting GenX. The anti-interference molecular imprinting sensor used for GenX detection of the present invention has the advantages of high specificity, strong stability and good anti-interference ability. The focus of the present invention is to create a method for preparing a dual-signal molecular imprinting sensor specifically for detecting GenX. This method aims to create a GenX molecular imprinting sensor with high selectivity, strong affinity, excellent stability and anti-interference performance by carefully adjusting the key links such as the screening of template molecules, the conception of functional monomers, the improvement of cross-linking agents, and the improvement of the stability of the imprinting cavity and the ability to resist external interference. This sensor is expected to be able to quickly and accurately identify GenX, providing solid scientific and technological support for environmental protection work and ecological risk assessment.

[0005] The preparation method of the dual-signal molecular imprinting sensor of the present invention includes five steps: preparation of gold nanoparticles / glassy carbon electrode (Au NPs / GCE), construction of Joule hot carbon material / gold nanoparticle interface (ECB / AuNPs / GCE), construction of built-in probe thionine (pThi@ECB / AuNPs / GCE), preparation of o-phenylenediamine (O-PD) and 3,4-ethylenedioxythiophene (EDOT) molecular imprinting sensitive film (MIP / pThi@ECB / AuNPs / GCE) and GenX analysis and detection. The present invention develops an ultra-sensitive electrochemical sensor for detecting GenX in groundwater by modifying AuNPs, Joule heat carbon material ECB, thionine built-in probe Thi, and MIP thin coating, wherein the MIP film is prepared by electrochemical polymerization of o-phenylenediamine (O-PD), 3,4-ethylenedioxythiophene (EDOT), and GenX on a glassy carbon electrode, wherein O-PD and EDOT serve as functional monomers for the formation of MIP, and GenX serves as a template molecule. The AuNPs coating helps to enhance the voltammetric response, the presence of ECB helps to stabilize the built-in probe, the introduction of the built-in probe helps to improve the sensitivity of the sensor, and the optimized setting of the MIP layer provides a higher peak change. The electrochemical sensor prepared by the present invention is used to detect GenX in water. After identification, GenX can block the imprinted cavity and combine with thionine through the action of ion pairs, so that the current signals of thionine and potassium ferrocyanide decrease, thereby realizing quantitative analysis of GenX. This sensor has the advantages of high specificity, strong stability, and good anti-interference ability.

[0006] The present invention is achieved through the following technical solutions: The first object of the present invention is to provide a dual-signal molecular imprinting sensor, comprising a base electrode, and gold nanoparticles, a Joule hot carbon material layer, a thionine built-in probe and a MIP film sequentially arranged on the surface of the base electrode, wherein the MIP film comprises a polymer monomer from which a GenX template molecule is removed.

[0007] In some embodiments of the present invention, the base electrode is a glassy carbon electrode.

[0008] In some embodiments of the present invention, the polymer monomer includes o-phenylenediamine (o-PD) and 3,4-ethylenedioxythiophene (EDOT); the molar ratio of o-phenylenediamine (o-PD) to 3,4-ethylenedioxythiophene (EDOT) is (1:1) to (10:1).

[0009] The second object of the present invention is to provide a method for preparing the dual-signal molecular imprinting sensor, comprising the following steps: Provide an Au NPs / GCE electrode; Applying Joule-heat carbon material ECB dispersed droplets on the surface of the Au NPs / GCE electrode and incubating to obtain an ECB / AuNPs / GCE electrode; Electropolymerizing thionine on the surface of the ECB / AuNPs / GCE electrode to obtain a pThi@ECB / AuNPs / GCE electrode containing a thionine built-in probe; An electrolyte containing polymer monomers and hexafluoropropylene ether diacid molecular imprinting templates is prepared, and electrochemical polymerization is performed at the interface of the pThi@ECB / AuNPs / GCE electrode. The hexafluoropropylene diacid molecular imprinting templates are then removed to obtain the dual-signal molecular imprinting sensor.

[0010] In some embodiments of the present invention, the concentration of the Joule hot carbon material ECB dispersion is 0.5-4 mg / mL.

[0011] In some embodiments of the present invention, the Joule heat carbon material ECB is made by heating carbon black to 1200-2000° C. in a Joule heat device.

[0012] In some embodiments of the present invention, the concentration of the electropolymerization solution of thionine is 1-5 mg / mL.

[0013] In some embodiments of the present invention, thionine electropolymerization is carried out by cyclic voltammetry (CV) under the following conditions: voltage of -0.4 to +1.1 V, CV polymerization cycles of 5 to 25, and polymerization scan rate of 25 to 125 mV / s.

[0014] In some embodiments of the present invention, the polymer monomer includes o-phenylenediamine (o-PD) and 3,4-ethylenedioxythiophene (EDOT); the molar ratio of o-phenylenediamine (o-PD) to 3,4-ethylenedioxythiophene (EDOT) is (1:1) to (10:1).

[0015] In some embodiments of the present invention, the electrochemical polymerization adopts cyclic voltammetry CV, under the following conditions: voltage of 0 ~ +1.0 V, CV polymerization cycles of 5 to 25, and polymerization scan rate of 25 to 125 mV / s.

[0016] Furthermore, after the molecular imprinting membrane was polymerized, the pThi@ECB / AuNPs / GCE electrode surface was rinsed with deionized water and eluted in an elution solution of acetic acid: water = (1:1) ~ (5:1) for 2-10 min to remove the GenX template molecules.

[0017] The third object of the present invention is to provide the application of the dual-signal molecular imprinting sensor in detecting GenX.

[0018] The above technical solution of the present invention has the following advantages compared with the prior art: 1. The present invention uses glassy carbon electrode (GCE) as a substrate, introduces a built-in probe based on the molecular imprinting recognition strategy, and successfully develops an ultra-sensitive electrochemical voltammetric sensor for hexafluoropropylene ether diacid (GenX) in groundwater. The sensor greatly enhances the electrochemical signal response by modifying the GCE surface with ECB / AuNPs coating. The introduction of the built-in probe thionine enhances the sensitivity of the sensor. In addition, the introduction of molecular imprinting polymer (MIP) film provides highly selective recognition capabilities for GenX, and further improves the sensitivity of detection through statistical optimization. The performance of the sensor in detecting GenX in groundwater is comparable to that of high-performance liquid chromatography-mass spectrometry, demonstrating its excellent analytical performance. The sensor preparation process covers five core stages: preparation of gold nanoparticles / glassy carbon electrode (Au NPs / GCE) (S1), construction of Joule hot carbon material / gold nanoparticle interface (ECB / AuNPs / GCE) (S2), construction of built-in probe thionine (pThi@ECB / AuNPs / GCE) (S3), preparation of o-phenylenediamine (O-PD) and 3,4-ethylenedioxythiophene (EDOT) molecular imprinted sensitive membrane (MIP / pThi@ECB / AuNPs / GCE) (S4) and GenX analysis and detection (S5). This series of steps endows the sensor with significant characteristics such as convenient operation, fast response, high sensitivity, strong specificity, good stability and excellent anti-interference ability in groundwater GenX detection.

[0019] 2. Electrochemical impedance spectroscopy (EIS) analysis and cyclic voltammetry (CV) were used to explore the electrochemical behavior of the electrode. In order to gain a deeper understanding of the electrochemical response of MIP / pThi@ECB / AuNPs / GCE in GenX recognition, differential pulse voltammetry (DPV) was used. In addition, differential pulse voltammetry (DPV) also assisted in revealing the variation of the electrical signal in the range of GenX concentration from 1 ng / L to 10μg / L, and a calibration curve was drawn accordingly. The entire preparation process has loose requirements on experimental equipment and conditions, is cost-effective, and is safe and convenient to operate. The developed electrochemical sensor exhibits excellent current response characteristics, outstanding stability, high repeatability, and good operability. By optimizing the electropolymerization process of MIP, we effectively reduced the risk of passivation on the electrode surface and the possibility of analyte saturation. These advantages make the sensor of great practical value for on-site rapid detection of GenX. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein: Figure 1 The electrochemical impedance spectroscopy and differential pulse voltammograms of AuNPs / GCE, ECB / AuNPs / GCE and PThi@ECB / AuNPs / GCE obtained in Example 1 of the present invention are shown; Figure 2 This is the cyclic voltammogram of the PThi@ECB / AuNPs / GCE polymerization obtained in Example 1 of the present invention; Figure 3 This is the cyclic voltammogram of MIP / PThi@ECB / AuNPs / GCE polymerization obtained in Example 1 of the present invention; Figure 4 Differential pulse voltammogram and calibration curve of the MIP / PThi@ECB / AuNPs / GCE sensor obtained in Example 2 of the present invention in the concentration range of 1 ng / L~10 μg / LGenX.

[0021] Figure 5 The calibration curves of the sensors obtained in Example 2 and Comparative Example 1 of the present invention in the GenX concentration range of 1 ng / L to 10 μg / L are shown.

[0022] Figure 6 This is a detection comparison between the MIP / PThi@ECB / AuNPs / GCE sensor of the present invention and liquid chromatography-mass spectrometry in real water samples.

[0023] Figure 7 This is a comparison of the specificity evaluation of the MIP / PThi@ECB / AuNPs / GCE sensor of the present invention.

[0024] Figure 8 This is an evaluation of the anti-interference performance of the MIP / PThi@ECB / AuNPs / GCE sensor of the present invention. DETAILED DESCRIPTION

[0025] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0026] Embodiment 1: The invention provides a method for preparing an anti-interference molecular imprinting sensor for detecting hexafluoropropylene ether diacid, comprising the steps of preparing gold nanoparticles / glassy carbon electrodes (Au NPs / GCE) S1; constructing a Joule hot carbon material / gold nanoparticle interface (ECB / AuNPs / GCE) S2; constructing a built-in probe thionine (pThi@ECB / AuNPs / GCE) S3; preparing an o-phenylenediamine (O-PD) and 3,4-ethylenedioxythiophene (EDOT) molecular imprinting sensitive film (MIP / pThi@ECB / AuNPs / GCE) S4; and performing GenX analysis and detection S5, as shown below: 1. Preparation of gold nanoparticles / glassy carbon electrode (Au NPs / GCE) S1 The operation steps are as follows: (1) Alumina slurry with a particle size of 0.05 μm was used as the polishing medium to mirror-polish the glassy carbon electrode (GCE). The GCE was then ultrasonically cleaned in 75% anhydrous ethanol and ultrapure water, respectively, to completely remove impurities on the electrode surface.

[0027] (2) The GCE electrode was immersed in a solution containing 5 ml of 0.5 M sulfuric acid and cleaned by scanning for 400 s using an electrochemical workstation. Afterwards, the electrode was rinsed with deionized water and dried naturally to obtain a pretreated GCE electrode.

[0028] (3) Add 8.5 ml of deionized water to 0.5 ml of chloroauric acid stock solution for dilution. First, a 15-second pulse was applied by chronoamperometry (CA) at an initial potential of 0.8 V to form gold nuclei on the surface of the pretreated GCE electrode obtained in step (2). Then, cyclic voltammetry (CV) was used to scan 50 cycles in the voltage range of -0.4 to +0.3 V to finally obtain a gold nanoparticle-modified glassy carbon electrode (Au NPs / GCE).

[0029] 2. Construction of Joule-heated carbon material / gold nanoparticle interface (ECB / AuNPs / GCE) S2 operation steps are as follows: Carbon black (CB) was placed in a Joule heat device, argon gas was passed in a closed space, and an electric current was passed to make the surface temperature of carbon black reach 1700 °C for 1.72 s, and then the Joule heat carbon material ECB was obtained. 1 mg of ECB powder was dissolved in 1 ml of sodium carboxymethyl cellulose solution and ultrasonically dispersed to obtain ECB suspension. 10 μL of ECB was drop-coated on the surface of the glassy carbon electrode modified with gold nanoparticles obtained in step 1, and dried at room temperature to obtain an ECB / AuNPs / GCE electrode.

[0030] 3. Construction of the built-in probe thionine (pThi@ECB / AuNPs / GCE) S3 operation steps are as follows: 10 mg of thionine was dissolved in 3 mL of PBS solution at pH = 6, and the ECB / AuNPs / GCE electrode obtained in step 2 was placed in the above thionine solution. Cyclic voltammetry (CV) was used to perform electropolymerization between -0.4 and +1.1 V, with a scan rate of 50 mV / s and 20 cycles. After the polymerization was completed, the electrode surface was rinsed with deionized water to obtain the pThi@ECB / AuNPs / GCE electrode.

[0031] 4. Preparation of o-phenylenediamine (O-PD) and 3,4-ethylenedioxythiophene (EDOT) molecular imprinted sensitive membrane (MIP / pThi@ECB / AuNPs / GCE) The S4 operation steps are as follows: (1) An electrolyte containing O-PD (polymer monomer), EDOT (polymer monomer), and GenX (molecular imprinting template, 1 mM) was prepared and dissolved in a mixture of acetonitrile and acetate buffer solution = 1:1 (volume ratio). Cyclic voltammetry (CV) was used to perform electrochemical polymerization between 0 and +1.0 V to obtain a MIP / pThi@ECB / AuNPs / GCE electrode. The results are shown in Figure 2~3 ,Depend on Figure 2 It can be seen from the main figure that as the number of polymerization cycles increases, the CV current increases, a conductive film is formed on the surface of the electrode, which is the conductive layer of PThi, and the built-in probe has been completely polymerized on the electrode surface. At the same time, it can be seen from the sub-figure that as the number of polymerization cycles increases, the increase in CV current decreases, indicating that the built-in probe polymerized on the electrode gradually tends to saturation.

[0032] Among them, the optimization parameters related to electrochemical polymerization mainly include the molar ratio of the two monomers (O-PD:EDOT = 10:1, 5:1, 3:1, 2:1, 1:1), the number of CV polymerization cycles (5, 10, 15, 20, 25), and the polymerization scan rate (25, 50, 75, 100, 125 mV / s). The optimization results show that the molar ratio of the two monomers is 3:1, the number of CV polymerization cycles is 10, and the polymerization scan rate is 50 mV / s. Figure 3 shown); (2) After the polymerization is completed, the surface of the MIP / pThi@ECB / AuNPs / GCE electrode is rinsed with deionized water and eluted in an eluent of acetic acid: water = 4:1 (volume ratio) for 6 min to remove the GenX template molecules and finally obtain an anti-interference molecular imprinting sensor.

[0033] 5. Structural characterization: In 5 mM [Fe(CN)6] 3- / 4- The electrochemical behavior of the electrode was characterized by electrochemical impedance spectroscopy and differential pulse voltammogram in 0.1 M KCl solution. Figure 1As shown in the EIS graph, it can be seen that as Au NPs, ECB and thionine are deposited on the electrode surface, the electron transfer ability of the electrode is enhanced and its charge transfer resistance (R ct ) is significantly smaller than GCE.

[0034] 6. The steps for analyzing and detecting GenX S5 are as follows: Differential pulse voltammetry (DPV) was used to measure the prepared MIP / pThi@ECB / AuNPs / GCE sensor in 5 mM [Fe(CN)6] 3− / 4− The measurement was carried out in a mixed solution with 0.1 M KCl, and the changes in the electrical signals of the potassium ferrocyanide probe and the thionine probe before and after GenX incubation were used to quantitatively analyze the GenX concentration in the water sample. The electrochemical measurement process includes pre-washing, incubation and detection. During pre-washing, MIP / pThi@ECB / AuNPs / GCE was gently rinsed with deionized water to clean the electrode surface; during incubation, it was incubated in 0.5 mL of a solution containing a certain concentration of GenX for 120 minutes; during detection, it was detected in a DPV potassium ferrocyanide solution.

[0035] Differential pulse voltammetry (DPV) was used to characterize the electrochemical responses of ECB@AuNPs / GCE (a), pThi / ECB@AuNPs / GCE (b), MIP / pThi@ECB / AuNPs / GCE without elution (c), MIP / pThi@ECB / AuNPs / GCE after removing GenX (d), and MIP / pThi@ECB / AuNPs / GCE after recognizing GenX (e). The results are shown in Figure 2. Figure 1 As shown in Figure 2, it can be seen that around 0.220 V, an obvious current response appears, and the current value decreases significantly because GenX hinders the electron transfer in the MIP cavity after recognition.

[0036] Embodiment 2: As an improvement on the previous embodiment, the preparation S4 of the MIP / pThi@ECB / AuNPs / GCE did not follow the traditional laboratory incubation method in GenX solution, but chose a method that is closer to the actual application environment, that is, directly immersing it in the standard sample for up to 120 minutes, and then performing DPV tests on these samples immersed in the standard sample according to the established steps and procedures.

[0037] The DPV test parameters have a potential range of -0.4 ~ 0.6 V (vs Ag / AgCl), a potential amplitude of 4 mV, a potential increment of 50 mV, a sampling width of 50 ms, and a pulse period of 500 ms.

[0038] Using the above technical solution, the differential pulse voltammogram and calibration curve in the concentration range of 1 ng / L~10 μg / L GenX are shown in the following table. Figure 4 As shown in the figure, it can be seen that the peak positions are approximately at -0.150 V and 0.220 V, and gradually decrease with the increase of GenX concentration. The logarithmic calibration curve shows that the developed sensor has a high sensitivity to GenX in the range of 1 ng / L~10 μg / L, and the correlation coefficient R 2 is 0.9918.

[0039] Comparative Example 1: As a comparison with Example 2, MIP / ECB / AuNPs / GCE without thionine modification was prepared. Except for the lack of step S3 of the built-in probe thionine modification, the other preparation steps were the same as MIP / pThi@ECB / AuNPs / GCE. It was immersed in the standard sample for 120 minutes, and the DPV test was performed on these samples immersed in the standard sample according to the established steps and procedures.

[0040] The potential range of the DPV test parameters is -0.4 ~ 0.6 V (vs Ag / AgCl), the potential amplitude is 4 mV, the potential increment is 50 mV, the sampling width is 50 ms, and the pulse period is 500 ms. The calibration curve is obtained in the concentration range of 1 ng / L~10 μg / L GenX. Within this range, the developed sensor has a high sensitivity to GenX, and the correlation coefficient R 2 is 0.9941, such as Figure 5 Compared with Example 2, the sensor modified with the built-in probe has a higher detection sensitivity to GenX.

[0041] Detection of GenX in Actual Groundwater In the complex water quality samples of groundwater, GenX was detected by liquid chromatography-mass spectrometry (LC-MS) and MIP / pThi@ECB / AuNPs / GCE sensor, respectively. The results are as follows: Figure 6 The average recoveries of samples detected by MIP / pThi@ECB / AuNPs / GCE ranged from 96.71% to 106.90%, with relative standard deviations (RSDs) ranging from 2.31% to 5.13%. This indicates that the prepared sensor is comparable to LC-MS in detecting GenX in complex water samples.

[0042] Anti-interference and specificity On the basis of the comparative example, in order to further illustrate the anti-interference performance of the prepared MIP / pThi@ECB / AuNPs / GCE and its specificity for GenX recognition, anti-interference experiments and specificity experiments were carried out.

[0043] Different types of perfluorinated analogs (PFBA, PFHpA, PFOA, PFOS) were used to test the specificity of the MIP / pThi@ECB / AuNPs / GCE electrode. The electrode without the template molecule GenX was used for comparison. The imprinting factor was used to evaluate the specificity of the electrode, which was calculated as a percentage (ΔI MIP / ΔI NIP ×100%), where ΔI MIP The DPV peak current change of MIP / pThi@ECB / AuNPs / GCE electrode before and after immersion in different perfluorinated solutions, ΔI NIP The DPV peak current changes of NIP / pThi@ECB / AuNPs / GCE electrode before and after immersion in different perfluorinated solutions. The DPV test parameters have a potential range of -0.4 ~ 0.6 V (vs Ag / AgCl), a potential amplitude of 4 mV, a potential increment of 50 mV, a sampling width of 50 ms, and a pulse period of 500 ms. Figure 7 It can be seen that MIP / pThi@ECB / AuNPs / GCE has a high specificity in recognizing GenX.

[0044] The anti-interference performance of MIP / pThi@ECB / AuNPs / GCE sensor was tested by comparing the detection results in the presence of salt ions (NaCl, CuCl2, HgNO3, ZnSO4), humic acid (HA), endocrine disruptors (BPA, PA) and 1 μg / L GenX. The anti-interference performance was evaluated using current changes, and the test method used was DPV. In the DPV test, the parameters had a potential range of -0.4 ~ 0.6 V (vs Ag / AgCl), a potential amplitude of 4 mV, a potential increment of 50 mV, a sampling width of 50 ms, and a pulse period of 500 ms. Figure 8 As shown, these seven types of interference have little effect on the accurate detection of GenX.

[0045] In summary, the prepared MIP / pThi@ECB / AuNPs / GCE sensor has good anti-interference ability and specificity.

[0046] The advantage is that this experimental technology does not require complex and expensive equipment, has extremely low cost, and is simple and clear to operate.

[0047] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.

Claims

1. A dual-signal molecular imprinting sensor, characterized in that: The invention comprises a basic electrode, and gold nanoparticles, a Joule heat carbon material layer, a thionine built-in probe and a MIP film which are sequentially arranged on the surface of the basic electrode, wherein the MIP film comprises a polymer monomer from which a GenX template molecule is removed.

2. The dual-signal molecular imprinting sensor according to claim 1, characterized in that: The base electrode is a glassy carbon electrode; the polymer monomers include o-phenylenediamine and 3,4-ethylenedioxythiophene.

3. The dual-signal molecular imprinting sensor according to claim 2, characterized in that: The molar ratio of o-phenylenediamine to 3,4-ethylenedioxythiophene is (1:1) to (10:1).

4. A method for preparing a dual-signal molecular imprinting sensor according to any one of claims 1 to 3, characterized in that: The following steps are involved: Provide an Au NPs / GCE electrode; Applying Joule-heat carbon material ECB dispersed droplets on the surface of the Au NPs / GCE electrode and incubating to obtain an ECB / AuNPs / GCE electrode; Electropolymerizing thionine on the surface of the ECB / AuNPs / GCE electrode to obtain a pThi@ECB / AuNPs / GCE electrode containing a thionine built-in probe; An electrolyte containing polymer monomers and hexafluoropropylene ether diacid molecular imprinting templates is prepared, and electrochemical polymerization is performed at the interface of the pThi@ECB / AuNPs / GCE electrode. The hexafluoropropylene diacid molecular imprinting templates are then removed to obtain the dual-signal molecular imprinting sensor.

5. The preparation method according to claim 4, characterized in that: The concentration of the Joule heat carbon material ECB dispersion is 0.5-4 mg / mL.

6. The preparation method according to claim 4, characterized in that: The concentration of the electropolymerization solution of thionine is 1-5 mg / mL.

7. The preparation method according to claim 4, characterized in that: The electropolymerization of thionine was carried out by cyclic voltammetry (CV) under the following conditions: voltage of -0.4 to +1.1 V, CV polymerization cycles of 5 to 25, and polymerization scan rate of 25 to 125 mV / s.

8. The preparation method according to claim 4, characterized in that: The electrochemical polymerization adopts cyclic voltammetry CV, and the conditions are: voltage is 0 ~ +1.0 V, CV polymerization cycle number is 5~25, and polymerization scan rate is 25~125 mV / s.

9. Use of the dual-signal molecular imprinting sensor according to any one of claims 1 to 3 in detecting GenX.

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