A dual-signal molecularly imprinted sensor, its preparation method and its application in detecting GenX

Abstract

The present invention provides a dual-signal molecularly imprinted sensor, a preparation method thereof, and an application thereof in detecting GenX. The dual-signal molecularly imprinted sensor of the present invention includes a base electrode, and a gold nanoparticle, a Joule heat carbon material layer, a thionine built-in probe, and an MIP thin film sequentially arranged on the surface of the base electrode. The MIP thin film includes a polymer monomer from which the GenX template molecule is removed. The present invention utilizes the ECB / AuNPs coating to help enhance the voltammetric response, and the optimized setting of the MIP layer provides a higher peak change. The prepared electrochemical sensor is used to detect GenX in water, and has the advantages of high specificity, strong stability, and good anti-interference ability.

Description

Technical Field

[0001] The present invention relates to the field of electrochemical sensing technology, and in particular to a preparation method of a molecularly imprinted sensor and its application in the detection of hexafluoropropylene ether diacid (GenX) in groundwater. Background Art

[0002] Hexafluoropropylene ether diacid (GenX) is a precursor molecule used in the manufacture of chemical-resistant and non-stick products. Due to its persistence and bioaccumulation in water bodies and soil, it poses a serious threat to human health and the ecological environment. Relevant reports have proven that the toxicity of GenX is higher than that of common long-chain perfluorocarbons. To identify pollution sources, rapid detection of GenX is required. Commonly used methods such as chromatography and mass spectrometry for detecting and quantifying GenX are costly and difficult to deploy as a means of continuous monitoring. In contrast, electrochemical sensors have the advantages of miniaturization, low cost, and high sensitivity. Electrochemical molecularly imprinted sensors, as a model application of molecular imprinting technology, are specifically designed to accurately identify specific target molecules. Its working principle lies in achieving efficient and specific capture of target molecules by precisely constructing an imprinted cavity that matches the shape, size, and functional groups of the target molecule. This sensor not only exhibits excellent selectivity and affinity but also has outstanding stability and a simple preparation process, providing strong technical support for various detection applications.

[0003] However, currently, electrochemical sensors for identifying GenX based on molecular imprinting technology still face some challenges during the preparation process. Low concentrations of GenX can pose a threat to the ecological environment. There is still a large room for improvement in the sensitivity of current molecularly imprinted sensors. Moreover, in complex environmental samples, there are a large number of compounds with structures similar to GenX, which may interfere with the detection of GenX and reduce the sensitivity and accuracy of the sensor. Summary of the Invention

[0004] To solve the above technical problems, the present invention provides a dual-signal molecularly imprinted sensor, its preparation method, and its application in the detection of GenX. The anti-interference molecularly imprinted sensor 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 molecularly imprinted sensor specifically for detecting GenX. This method aims to create a GenX molecularly imprinted sensor with high selectivity, strong affinity, excellent stability, and anti-interference performance by carefully adjusting key aspects such as the screening of template molecules, the design of functional monomers, the improvement of cross-linking agents, and the enhancement of the stability of the imprinted cavity and its anti-external interference ability. This sensor is expected 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 molecularly imprinted sensor of the present invention includes the preparation of gold nanoparticles / glassy carbon electrode (Au NPs / GCE), the construction of the electrothermal carbon material / gold nanoparticle interface (ECB / AuNPs / GCE), the construction of the built-in probe thionine (pThi@ECB / AuNPs / GCE), the preparation of the o-phenylenediamine (O-PD), 3,4-ethylenedioxythiophene (EDOT) molecularly imprinted sensitive film (MIP / pThi@ECB / AuNPs / GCE), and the GenX analysis and detection. Through the modification of AuNPs, electrothermal carbon material ECB, thionine built-in probe Thi, and MIP thin coating, the present invention developed a super-sensitive electrochemical sensor for detecting GenX in groundwater. The MIP thin film was prepared by electrochemically polymerizing o-phenylenediamine (O-PD), 3,4-ethylenedioxythiophene (EDOT), and GenX on the glassy carbon electrode. O-PD and EDOT were used as functional monomers for MIP formation, and GenX was used as the 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 recognition, GenX can block the imprinted cavity and bind to thionine through the action of ion pairs, resulting in a decrease in the current signals of thionine and potassium ferricyanide, thereby realizing the quantitative analysis of GenX. This kind of sensor has the advantages of high specificity, strong stability, and good anti-interference ability.

[0006] The present invention realizes the present invention through the following technical solutions:

[0007] The first object of the present invention is to provide a dual-signal molecularly imprinted sensor, including a basic electrode, and gold nanoparticles, an electrothermal carbon material layer, a thionine built-in probe, and an MIP thin film sequentially arranged on the surface of the basic electrode. The MIP thin film includes polymer monomers with the GenX template molecule removed.

[0008] In some embodiments of the present invention, the basic electrode is a glassy carbon electrode.

[0009] In some embodiments of the present invention, the polymer monomers include 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).

[0010] The second object of the present invention is to provide a preparation method of the dual-signal molecularly imprinted sensor, including the following steps:

[0011] Provide an Au NPs / GCE electrode;

[0012] Drop-coat the Joule-heated carbon material ECB dispersion on the surface of the Au NPs / GCE electrode and incubate to obtain the ECB / Au NPs / GCE electrode;

[0013] Electropolymerize thionine on the surface of the ECB / Au NPs / GCE electrode to obtain the pThi@ECB / Au NPs / GCE electrode containing the thionine built-in probe;

[0014] Prepare an electrolyte containing a polymer monomer and a hexafluoropropylene ether diacid molecular imprinting template, and perform electrochemical polymerization at the interface of the pThi@ECB / Au NPs / GCE electrode. Then remove the hexafluoropropylene ether diacid molecular imprinting template to obtain the double-signal molecularly imprinted sensor.

[0015] In some embodiments of the present invention, the concentration of the Joule-heated carbon material ECB dispersion is 0.5 - 4 mg / mL.

[0016] In some embodiments of the present invention, the Joule-heated carbon material ECB is made by heating carbon black in a Joule heating device to 1200 - 2000 °C.

[0017] In some embodiments of the present invention, the concentration of the thionine electropolymerization solution is 1 - 5 mg / mL.

[0018] In some embodiments of the present invention, the thionine electropolymerization uses cyclic voltammetry CV, and the conditions are: the voltage is -0.4 ~ +1.1 V, the number of CV polymerization cycles is 5 - 25, and the polymerization scan rate is 25 - 125 mV / s.

[0019] 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) ~ (10:1).

[0020] In some embodiments of the present invention, the electrochemical polymerization uses cyclic voltammetry CV, and the conditions are: the voltage is 0 ~ +1.0 V, the number of CV polymerization cycles is 5 - 25, and the polymerization scan rate is 25 - 125 mV / s.

[0021] Further, after the molecularly imprinted membrane is polymerized, rinse the surface of the pThi@ECB / Au NPs / GCE electrode with deionized water and perform elution in an eluent with acetic acid:water = (1:1) ~ (5:1) for 2 - 10 min to remove the GenX template molecules.

[0022] The third object of the present invention is to provide the application of the double-signal molecularly imprinted sensor in detecting GenX.

[0023] The above technical solution of the present invention has the following advantages compared with the prior art:

[0024] 1. The present invention uses a glassy carbon electrode (GCE) as a substrate, introduces an internal probe on the basis of a molecular imprinting recognition strategy, and successfully develops a super-sensitive electrochemical voltammetric sensor for hexafluoropropylene ether diacid (GenX) in groundwater. The sensor modifies the surface of the GCE through an ECB / AuNPs coating, greatly enhancing the electrochemical signal response. The introduction of the internal probe thionine enhances the sensitivity of the sensor. In addition, the introduction of a molecularly imprinted polymer (MIP) film provides a highly selective recognition ability for GenX, and through statistical means optimization, further improves the detection sensitivity. The performance of the sensor in the detection of GenX in groundwater is comparable to that of high performance liquid chromatography-mass spectrometry, demonstrating its excellent analytical efficiency. The preparation process of the sensor covers five core stages: the preparation of gold nanoparticles / glassy carbon electrode (Au NPs / GCE) (S1), the construction of the electrothermal carbon material / gold nanoparticle interface (ECB / AuNPs / GCE) (S2), the construction of the internal probe thionine (pThi@ECB / AuNPs / GCE) (S3), the preparation of the o-phenylenediamine (O-PD), 3,4-ethylenedioxythiophene (EDOT) molecularly imprinted sensitive film (MIP / pThi@ECB / AuNPs / GCE) (S4), and the analysis and detection of GenX (S5). This series of steps endows the sensor with remarkable characteristics such as convenient operation, rapid response, high sensitivity, strong specificity, good stability and excellent anti-interference ability in the detection of GenX in groundwater.

[0025] 2. When deeply exploring the electrochemical behavior of the electrode, electrochemical impedance spectroscopy (EIS) analysis and cyclic voltammetry (CV) are adopted. In order to more deeply understand the electrochemical response of MIP / pThi@ECB / AuNPs / GCE in the recognition of GenX, differential pulse voltammetry (DPV) is used. In addition, differential pulse voltammetry (DPV) also helps to reveal the change law of the electrical signal in the range of GenX concentration from 1 ng / L to 10 μg / L, and a calibration curve is drawn accordingly. The entire preparation process has loose requirements for experimental devices and conditions, is cost-effective, and is safe and convenient to operate. The developed electrochemical sensor exhibits excellent current response characteristics, excellent stability, high repeatability and good operability. By optimizing the electropolymerization process of MIP, we effectively reduce the risk of passivation of the electrode surface and the possibility of analyte saturation. These advantages make the sensor of great practical value for the on-site rapid detection of GenX. Description of the Drawings

[0026] In order to make the content of the present invention easier to be clearly understood, the following further details the present invention according to the specific embodiments of the present invention in conjunction with the accompanying drawings, wherein,

[0027] Figure 1 Electrochemical impedance diagrams and differential pulse voltammograms of AuNPs / GCE, ECB / AuNPs / GCE, and PThi@ECB / AuNPs / GCE obtained in Example 1 of the present invention;

[0028] Figure 2 Cyclic voltammogram of the polymerization of PThi@ECB / AuNPs / GCE obtained in Example 1 of the present invention;

[0029] Figure 3 Cyclic voltammogram of the polymerization of MIP / PThi@ECB / AuNPs / GCE obtained in Example 1 of the present invention;

[0030] 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 GenX concentration range of 1 ng / L to 10 μg / L.

[0031] Figure 5 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.

[0032] Figure 6 Detection comparison of the MIP / PThi@ECB / AuNPs / GCE sensor of the present invention and liquid chromatography-mass spectrometry in real water samples.

[0033] Figure 7 Specificity evaluation comparison of the MIP / PThi@ECB / AuNPs / GCE sensor of the present invention.

[0034] Figure 8 Anti-interference performance evaluation of the MIP / PThi@ECB / AuNPs / GCE sensor of the present invention. Specific Embodiments

[0035] The following further illustrates the present invention in conjunction with the accompanying drawings and specific embodiments, so that those skilled in the art can better understand the present invention and be able to implement it, but the examples given are not intended to limit the present invention.

[0036] Example 1:

[0037] The preparation method of an anti-interference molecularly imprinted sensor for the detection of hexafluoropropylene ether diacid provided by the present invention includes the preparation of gold nanoparticles / glassy carbon electrode (Au NPs / GCE) S1; the construction of a Joule-heated carbon material / gold nanoparticle interface (ECB / AuNPs / GCE) S2; the construction of an internal probe thionine (pThi@ECB / AuNPs / GCE) S3; the preparation of an o-phenylenediamine (O-PD), 3,4-ethylenedioxythiophene (EDOT) molecularly imprinted sensitive film (MIP / pThi@ECB / AuNPs / GCE) S4; and the GenX analysis and detection S5, which are specifically as follows:

[0038] I. The operation steps of the preparation of gold nanoparticles / glassy carbon electrode (Au NPs / GCE) S1 are as follows:

[0039] (1) Using alumina slurry with a particle size of 0.05 μm as a polishing medium, the glassy carbon electrode (GCE) is mirror-polished, and then ultrasonically cleaned in anhydrous ethanol with a concentration of 75% and ultrapure water respectively to thoroughly remove impurities on the electrode surface.

[0040] (2) Immerse the GCE electrode in a solution containing 5 ml of 0.5 M sulfuric acid, and perform a 400 s scanning cleaning on it using an electrochemical workstation. After that, rinse the electrode with deionized water and dry it naturally to obtain a pretreated GCE electrode.

[0041] (3) Add 8.5 ml of deionized water to 0.5 ml of chloroauric acid stock solution for dilution. First, at an initial potential of 0.8 V, apply a 15 s pulse by chronoamperometry (CA) to form gold nuclei on the surface of the pretreated GCE electrode obtained in step (2). Then, perform 50 cycles of scanning in the voltage range of -0.4 to +0.3 V using cyclic voltammetry (CV) to finally obtain a gold nanoparticle-modified glassy carbon electrode (Au NPs / GCE).

[0042] II. The operation steps of the construction of a Joule-heated carbon material / gold nanoparticle interface (ECB / AuNPs / GCE) S2 are as follows:

[0043] Place carbon black (CB) in a Joule heating device, pass argon in a closed space, pass an electric current to make the surface temperature of the carbon black reach 1700 °C for 1.72 s, and then obtain the Joule-heated carbon material ECB. Dissolve 1 mg of ECB powder in 1 ml of sodium carboxymethyl cellulose solution and disperse it by ultrasonic wave to obtain an ECB suspension. Drop 10 μL of ECB onto the surface of the gold nanoparticle-modified glassy carbon electrode obtained in step one and dry it at room temperature to obtain an ECB / AuNPs / GCE electrode.

[0044] III. Construction of the built-in probe thionine (pThi@ECB / AuNPs / GCE) The S3 operation steps are as follows:

[0045] Dissolve 10 mg of thionine in 3 mL of PBS solution with pH = 6. Place the ECB / AuNPs / GCE electrode obtained in Step 2 into the above thionine solution, and perform electropolymerization between -0.4 V and +1.1 V using cyclic voltammetry (CV) at a scan rate of 50 mV / s for 20 cycles. After polymerization is completed, rinse the surface of the electrode with deionized water to obtain the pThi@ECB / AuNPs / GCE electrode.

[0046] IV. Preparation of the o-phenylenediamine (O-PD), 3,4-ethylenedioxythiophene (EDOT) molecularly imprinted sensitive film (MIP / pThi@ECB / AuNPs / GCE) The S4 operation steps are as follows:

[0047] (1) Prepare an electrolyte solution containing O-PD (polymer monomer), EDOT (polymer monomer), and GenX (molecular imprinting template, 1 mM), dissolve it in a mixture of acetonitrile:acetic acid buffer = 1:1 (volume ratio), and perform electrochemical polymerization between 0 V and +1.0 V using cyclic voltammetry (CV) to obtain the MIP / pThi@ECB / AuNPs / GCE electrode; the results are shown in Figures 2 - 3 , and it can be seen from Figure 2 that: as can be seen from the main figure, as the number of polymerization cycles increases, the current of CV increases, and a conductive film is formed on the surface of the electrode, which is the conductive layer of PThi. The built-in probe has been completely polymerized on the surface of the electrode. At the same time, as can be seen from the sub-figure, as the number of polymerization cycles increases, the increase amplitude of the CV current decreases, indicating that the built-in probe polymerized on the electrode gradually tends to saturation.

[0048] Among them, optimizing the relevant parameters of electrochemical polymerization mainly includes 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 optimized results show that the best molar ratio of the two monomers is 3:1, the number of CV polymerization cycles is 10 cycles, and the polymerization scan rate is 50 mV / s (as shown in Figure 3 );

[0049] (2) After polymerization is completed, rinse the surface of the MIP / pThi@ECB / AuNPs / GCE electrode with deionized water, and perform elution in an eluent of acetic acid:water = 4:1 (volume ratio) for 6 min to remove the GenX template molecule, and finally obtain an anti-interference molecularly imprinted sensor.

[0050] V. Structural Characterization: In a 5 mM [Fe(CN)6] 3- / 4- (0.1 M KCl) solution, the electrochemical impedance spectroscopy and differential pulse voltammetry were used to characterize the electrochemical behavior of the electrode. The results are as Figure 1 shown. It can be seen from the EIS diagram that with the deposition of Au NPs, ECB, and thionine on the electrode surface, the electron transfer ability of the electrode is enhanced, and its charge transfer resistance (R ct ) is significantly smaller than that of the GCE.

[0051] VI. The analysis and detection of GenX in S5 operation steps are as follows:

[0052] Using differential pulse voltammetry (DPV), the prepared MIP / pThi@ECB / AuNPs / GCE sensor was placed in a mixture of 5 mM [Fe(CN)6] 3− / 4− and 0.1 M KCl for measurement. By using the changes in the electrical signals of the potassium ferricyanide probe and thionine probe before and after incubation with GenX, the concentration of GenX in the water sample was quantitatively analyzed. The process of electrochemical measurement includes pre-washing, incubation, and detection. During pre-washing, the 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 GenX solution with a certain concentration for 120 minutes; during detection, it was detected in a potassium ferricyanide solution using DPV.

[0053] 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 as Figure 1 shown. It can be seen that near 0.220 V, an obvious current response appeared. Since the electron transfer in the MIP cavity was hindered after GenX recognition, the current value decreased significantly.

[0054] Example 2:

[0055] As an improvement to the previous example, the preparation S4 of the MIP / pThi@ECB / AuNPs / GCE did not follow the traditional method of incubating in a GenX solution in the laboratory. Instead, a more practical application environment approach was selected, that is, it was directly immersed in the standard sample for up to 120 minutes. Subsequently, according to the established steps and procedures, DPV tests were performed on these samples immersed in the standard sample.

[0056] For the DPV test, the potential range of the parameters is -0.4 to 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.

[0057] Through the above technical solution, the differential pulse voltammograms and calibration curves in the GenX concentration range of 1 ng / L to 10 μg / L are as follows Figure 4 shown. 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 the GenX concentration. The logarithmic calibration curve shows that in the range of 1 ng / L to 10 μg / L, the developed sensor has high sensitivity to GenX, and the correlation coefficient R 2 is 0.9918.

[0058] Comparative Example 1:

[0059] As a comparison with Example 2, MIP / ECB / AuNPs / GCE without thionine modification was prepared. Except for lacking the step S3 of the built-in probe thionine modification, the other preparation steps were the same as those of MIP / pThi@ECB / AuNPs / GCE. It was immersed in the standard sample for 120 minutes, and according to the established steps and procedures, DPV tests were carried out on these samples immersed in the standard sample.

[0060] The potential range of the parameters of the DPV test is -0.4 to 0.6 V (vs Ag / AgCl), the potential amplitude is 4 mV, the potential increment is 50 mV, the sampling width is 50 ms, the pulse period is 500 ms, a calibration curve was obtained in the GenX concentration range of 1 ng / L to 10 μg / L, and in this range, the developed sensor has high sensitivity to GenX, and the correlation coefficient R 2 is 0.9941, as Figure 5 shown. Compared with Example 2, the sensor modified with the built-in probe has higher detection sensitivity to GenX.

[0061] Detection of GenX in actual groundwater

[0062] In complex water quality samples of groundwater, GenX was detected by liquid chromatography - mass spectrometry (LC-MS) and MIP / pThi@ECB / AuNPs / GCE sensor respectively, and the results are as Figure 6As shown, the average recovery rate of the samples detected by MIP / pThi@ECB / AuNPs / GCE was 96.71% to 106.90%, and the relative standard deviation (RSD) was 2.31% to 5.13%. This indicates that the prepared sensor can be comparable to LC-MS when detecting GenX in complex water samples.

[0063] Anti-interference and specificity

[0064] On the basis of the comparative example, in order to further illustrate the anti-interference performance and the specificity for GenX recognition of the prepared MIP / pThi@ECB / AuNPs / GCE, anti-interference experiments and specificity experiments were carried out.

[0065] Different types of perfluorinated analogues (PFBA, PFHpA, PFOA, PFOS) were used to test the specificity of the MIP / pThi@ECB / AuNPs / GCE electrode. An electrode without adding the template molecule GenX was used for comparison. The imprinting factor was used to evaluate the specificity of the electrode. The calculation formula is percentage (ΔI MIP / ΔI NIP ×100%), where ΔI MIP represents the change in the DPV peak current of the MIP / pThi@ECB / AuNPs / GCE electrode before and after being immersed in different perfluorinated solutions, and ΔI NIP represents the change in the DPV peak current of the NIP / pThi@ECB / AuNPs / GCE electrode before and after being immersed in different perfluorinated solutions. For the DPV test, the potential range of the parameters was -0.4 ~ 0.6 V (vs Ag / AgCl), the potential amplitude was 4 mV, the potential increment was 50 mV, the sampling width was 50 ms, and the pulse period was 500 ms. It can be seen from Figure 7 that MIP / pThi@ECB / AuNPs / GCE has high specificity for the recognition of GenX.

[0066] The anti-interference performance of the MIP / pThi@ECB / AuNPs / GCE sensor was tested by comparing the detection results when salt ions (NaCl, CuCl2, HgNO3, ZnSO4), humic acid (HA), endocrine disruptors (BPA, PA) and 1 μg / L GenX coexisted. The current change was used to evaluate the anti-interference performance, and the DPV method was used for the test. For the DPV test, the potential range of the parameters was -0.4 ~ 0.6 V (vs Ag / AgCl), the potential amplitude was 4 mV, the potential increment was 50 mV, the sampling width was 50 ms, and the pulse period was 500 ms. As Figure 8 shown, these 7 types of interferences had little effect on the accurate detection of GenX.

[0067] In summary, the prepared MIP / pThi@ECB / AuNPs / GCE sensor has good anti-interference ability and specificity.

[0068] The advantages are that this experimental technique does not require complex and expensive equipment, has extremely low costs, and is simple and clear to operate.

[0069] Obviously, the above embodiments are only examples given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill 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 manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A dual-signal molecularly imprinted sensor, characterized in that, It includes a base electrode, and successively arranged on the surface of the base electrode are gold nanoparticles, a Joule heat carbon material layer, a thionine built-in probe, and a MIP film. The MIP film includes polymer monomers from which the GenX template molecules have been removed; the base electrode is a glassy carbon electrode; the polymer monomers include o-phenylenediamine and 3,4-ethylenedioxythiophene.

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

3. A preparation method of the dual-signal molecularly imprinted sensor according to any one of claims 1 to 2, characterized in that, It includes the following steps: Provide an Au NPs / GCE electrode; Drop-coat the dispersion liquid of the Joule heat carbon material ECB on the surface of the Au NPs / GCE electrode and incubate it to obtain an ECB / AuNPs / GCE electrode; Electro-polymerize thionine on the surface of the ECB / AuNPs / GCE electrode to obtain a pThi@ECB / AuNPs / GCE electrode containing a thionine built-in probe; Prepare an electrolytic solution containing polymer monomers and a hexafluoropropylene ether diacid molecular imprinting template, and perform electrochemical polymerization at the interface of the pThi@ECB / AuNPs / GCE electrode. Then remove the hexafluoropropylene ether diacid molecular imprinting template to obtain the dual-signal molecularly imprinted sensor.

4. The preparation method according to claim 3, characterized in that, The concentration of the dispersion liquid of the Joule heat carbon material ECB is 0.5 - 4 mg / mL.

5. The preparation method according to claim 3, characterized in that, The concentration of the electro-polymerization solution of thionine is 1 - 5 mg / mL.

6. The preparation method according to claim 3, characterized in that, The electro-polymerization of thionine uses cyclic voltammetry CV, and the conditions are: the voltage is -0.4 to +1.1 V, the number of CV polymerization cycles is 5 - 25, and the polymerization scanning rate is 25 - 125 mV / s.

7. The preparation method according to claim 3, characterized in that, The polymer monomers include o-phenylenediamine and 3,4-ethylenedioxythiophene; the molar ratio of o-phenylenediamine to 3,4-ethylenedioxythiophene is (1:1) to (10:1).

8. The preparation method according to claim 3, wherein The electrochemical polymerization uses cyclic voltammetry CV, and the conditions are: the voltage is 0 to +1.0 V, the number of CV polymerization cycles is 5 - 25, and the polymerization scanning rate is 25 - 125 mV / s.

9. Application of the dual-signal molecularly imprinted sensor according to any one of claims 1 to 2 in detecting hexafluoropropylene ether diacid.

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