Molecularly imprinted electrochemiluminescent sensor based on Zn-PTC and its preparation method and application

Abstract

The present invention relates to the field of electrochemical detection technology, and discloses a molecular imprinting electrochemiluminescence sensor based on Zn-PTC, a preparation method thereof, and an application in detecting ENR. The construction process includes a glassy carbon electrode, a Zn-PTC layer, an electrochemically active chitosan layer, and a polypyrrole layer with an ENR-specific imprinting cavity to be detected, which are sequentially modified from the inside to the outside. When detecting ENR, the Ppy-MIP / CHIT / Zn-PTC / GCE modified electrode is used as the working electrode, the Ag / AgCl electrode is used as the reference electrode, and the platinum electrode is used as the auxiliary electrode, and the electrochemiluminescence method is used for detection. The linear range of the sensor is 1.0×10 ‑4 ~1.0×10 ‑ 12 mol / L, the detection limit is 3.3×10 ‑13 mol / L. The sensor prepared by the present invention has the advantages of high detection sensitivity, fast detection speed, and convenient use.

Description

Technical Field

[0001] The invention relates to the technical field of enrofloxacin (ENR) detection, and in particular to a molecular imprinting electrochemiluminescence sensor based on Zn-PTC and a preparation method and application thereof. Background Art

[0002] Enrofloxacin (ENR) is a quinolone antibiotic that is widely used in animal husbandry and aquaculture due to its broad antibacterial spectrum, strong antibacterial effect and low toxicity. However, ENR is generally not retained in the body. When the dose is large, some ENR and its metabolites will remain in the liver and kidneys of animals. Therefore, the detection of ENR is particularly important. Traditional detection methods for ENR usually include: high performance liquid chromatography (HPLC), capillary electrophoresis (CE), chemiluminescence, electrochemical fluorescence and high performance liquid chromatography-mass spectrometry (HPLC-MS). However, most of these methods require special instruments, long working time, cumbersome pretreatment, and high related costs. Compared with these methods, electrochemiluminescence has the advantages of high sensitivity, low cost, low detection limit and wide linear range. It has been widely used in the detection of pesticides, molds, etc. and has been widely used in the field of analysis. For example, the Chinese patent document (application number 202010082900.0) discloses a method for preparing an imprinted electroluminescent sensor for enrofloxacin detection. The electrochemical sensor is prepared based on copper nanoclusters, but its detection sensitivity is limited, and the detection sensitivity for low-concentration enrofloxacin needs to be further improved. Summary of the invention

[0003] In order to overcome the above-mentioned problems in the prior art and further improve the sensitivity of electrochemiluminescence detection of enrofloxacin, the present invention is based on molecular imprinting polypyrrole on Zn-PTC and CHIT modified electrodes for ultra-sensitive selective detection of ENR. The sensor achieves elution and detection of ENR molecules by breaking and forming hydrogen bonds between Ppy and ENR. The conventional three-electrode system is used to test the ECL performance of molecular imprinting electrochemical sensor (MIECS) based on electrochemiluminescence (ECL). The sensor has the advantages of high detection sensitivity, fast detection speed and easy use.

[0004] The first object of the present invention is to provide a molecular imprinting electrochemiluminescence sensor based on Zn-PTC (also known as Ppy-MIP / CHIT / Zn-PTC / GCE molecular imprinting electrochemiluminescence sensor) for the detection of ENR, comprising a glassy carbon electrode, a Zn-PTC layer modified on the surface of the glassy carbon electrode from the inside to the outside, a chitosan (CHIT) layer with electrochemical activity, and a polypyrrole layer with a specific imprinting cavity for the ENR to be detected. The present invention combines Zn-PTC with enrofloxacin to produce a significant fluorescence change, and at the same time utilizes the network structure of chitosan to enhance the contact specific surface area of ​​the electropolymerized molecular imprinting polymer film, increase the electron transfer rate, thereby increasing the electrical signal, effectively improving the detection sensitivity, and enhancing the stability of the molecular imprinting film on the glassy carbon electrode. The detection range of the sensor of the present invention is 1.0×10 -12 mol / L~1.0×10 -4 mol / L, the detection limit is 3.3×10 -13 mol / L, it has the advantages of high detection sensitivity, fast detection speed and easy use.

[0005] The above-mentioned Zn-PTC is obtained by the following method: K4PTC is slowly added to an aqueous solution of Zn(CH3COO)2 and stirred at room temperature, and the mixture is transferred to an autoclave lined with Teflon and heated for reaction. After the reaction is completed, it is washed with ethanol and deionized water in sequence, and the orange Zn-PTC solid product is collected by centrifugation.

[0006] Furthermore, the molar ratio of K4PTC to Zn(CH3COO)2 was 1:2, specifically, 0.05 mmol K4PTC was slowly added to 15 mL deionized water containing 0.1 mmol Zn(CH3COO)2 and stirred at room temperature. The mixture was transferred to a Teflon-lined autoclave and heated at 100°C for 12 h.

[0007] The preparation method of the Ppy-MIP / CHIT / Zn-PTC / GCE molecular imprinting electrochemiluminescence sensor comprises the following steps: polishing a glassy carbon electrode, ultrasonicating with nitric acid, anhydrous ethanol and deionized water in sequence, drop-coating a Zn-PTC suspension on the surface of the glassy carbon electrode, and drying under an infrared lamp to obtain Zn-PTC / GCE; then drop-coating an acetic acid solution of CHIT on the surface of the Zn-PTC / GCE, and drying at room temperature to obtain CHIT / Zn-PTC / GCE; placing the prepared CHIT / Zn-PTC / GCE in a phosphate buffer containing Py monomer and ENR. In the flushing liquid, in a three-electrode system, Py is electropolymerized to the surface of CHIT / Zn-PTC / GCE by cyclic voltammetry to generate a Ppy film; wherein ENR is connected with Ppy through hydrogen bonds formed between Ppy and is doped in Ppy to obtain Ppy-MIP-ENR / CHIT / Zn-PTC / GCE; Ppy-MIP-ENR / CHIT / Zn-PTC / GCE is placed in a NaOH:ethanol solution to soak and elute the ENR doped in the Ppy film to obtain a Ppy-MIP / CHIT / Zn-PTC / GCE molecular imprinting electrochemiluminescence sensor.

[0008] Furthermore, the preparation method of the Zn-PTC suspension is as follows: adding Zn-PTC powder to deionized water and stirring ultrasonically until a uniform suspension is formed, the Zn-PTC content in the suspension is 0.5 mg / mL, and the modification amount is 5.0 μL;

[0009] And / or, the modified volume of CHIT solution is 5.0 μL.

[0010] Further, in the CHIT acetic acid solution, the concentration of CHIT is 0.25 wt %; and the concentration of acetic acid is 1.0 wt %.

[0011] Furthermore, a 0.25 wt % CHIT solution was prepared by dissolving 0.25 g chitosan in 100 mL 1% acetic acid solution to prepare a chitosan solution, stirring the solution vigorously at room temperature, and storing the solution at low temperature for later use.

[0012] Furthermore, the potential range of cyclic voltammetry electropolymerization: 0-1.2 V; number of scans: 15; electrolyte: PBS buffer containing Py and ENR, pH 7.0;

[0013] And / or, a mixed solution of NaOH and ethanol is used as the eluent of ENR, the volume ratio of the two is 3:1, the NaOH concentration is 0.1 mol / L, and the soaking and elution time is 15 min.

[0014] The present invention also provides a method for detecting ENR samples using the above-mentioned Ppy-MIP / CHIT / Zn-PTC / GCE molecular imprinting electrochemiluminescence sensor, comprising the following steps: (1) preparing a phosphate buffer solution (PBS) and a PBS containing potassium persulfate (K2S2O8); (2) preparing PBS containing different concentrations of ENR; and (3) drawing a standard curve and determining a linear equation.

[0015] A1. PBS contains 0.05 mol / L K2S2O8, the pH of PBS buffer solution is 7.4, and its concentration is 0.1 mol / L.

[0016] A2. Accurately weigh a certain amount of ENR and prepare 1.0×10 -4 mol / L solution, a certain amount of ENR solution was added into PBS containing 0.1 mol / L pH 7.4 to obtain a series of ENR standard solutions with different concentrations, ranging from 1.0×10 - 12 mol / L~1.0×10 -4 mol / L.

[0017] A3. Ppy-MIP / CHIT / Zn-PTC / GCE was used as the working electrode, platinum electrode as the auxiliary electrode, and Ag / AgCl as the reference electrode. In the electrochemical window range of -1.7 to 0 V, the photomultiplier tube high voltage was 800 V, the scan rate was 0.1 V / s, and cyclic voltammetry was performed to record the time-luminescence intensity curve (T-ECL). The ECL intensity of the sensor was detected in PBS containing different concentrations of ENR, and the linear relationship between the ECL intensity and the logarithm of the ENR concentration was established to obtain the corresponding linear regression equation.

[0018] Compared with the prior art, the present invention has the following technical advantages: the present invention combines Zn-PTC with enrofloxacin to produce significant fluorescence changes, and at the same time utilizes the chitosan network structure to enhance the contact specific surface area of ​​the electropolymerized molecular imprinted polymer film, increase the electron transfer rate, thereby increasing the electrical signal, effectively improving the detection sensitivity, and enhancing the stability of the molecular imprinted film on the glassy carbon electrode. The detection range of the sensor of the present invention is 1.0×10 -12 mol / L~1.0×10 -4 mol / L, the detection limit is 3.3×10 -13 mol / L, it has the advantages of high detection sensitivity, fast detection speed and easy use. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0020] Figure 1 is a brief flow chart of the preparation of Ppy-MIP / CHIT / Zn-PTC / GCE and its use for ENR detection;

[0021] Figure 2 The ECL curves of different modified electrodes in 0.1 mol / L PBS containing 0.05 mol / L K2S2O8 (a. GCE; b. CHIT / Zn-PTC / GCE; c. Ppy-MIP-ENR / CHIT / Zn-PTC / GCE; d. Ppy-MIP / CHIT / Zn-PTC / GCE; e. Ppy-MIP / CHIT / Zn-PTC / GCE recombined with 1.0×10 -4 mol / L of ENR (curve c indicates: in the presence of ENR, Py is electropolymerized in the range of 0 to 1.2 V, at which time ENR is doped in the Ppy film; curve d indicates that ENR molecules are eluted in NaOH solution, at which time many ENR-specific cavities are formed on the electrode surface; curve e indicates: the sensor rebinds with ENR molecules, at which time most of the cavities on the electrode surface are filled with EMR molecules);

[0022] Figure 3 It is the ECL signal of Ppy-MIP / CHIT / Zn-PTC / GCE in 0.1 mol / L PBS containing different concentrations of ENR.

[0023] Figure 4 It is the linear relationship between the logarithm of ENR concentration and ECL intensity in 0.1 mol / L PBS containing different concentrations of ENR. DETAILED DESCRIPTION

[0024] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, a Ppy-MIP / CHIT / Zn-PTC / GCE molecular imprinting electrochemiluminescence sensor proposed in accordance with the present invention, its specific implementation method, characteristics and effects are described in detail as follows.

[0025] Embodiment: A preparation method and application method of a Ppy-MIP / CHIT / Zn-PTC / GCE molecular imprinting electrochemiluminescence sensor.

[0026] A preparation method of a Ppy-MIP / CHIT / Zn-PTC / GCE molecular imprinting electrochemiluminescence sensor:

[0027] S1. Zn-PTC was obtained by the following method: 1 mmol of perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) and 5 mmol of KOH were dissolved in 4 mL of deionized water by ultrasound and stirred at 60 °C for 10 h. 30 mL of anhydrous ethanol was added to the above solution to obtain golden K4PTC. Subsequently, 0.05 mmol of K4PTC was slowly added to 15 mL of deionized water containing 0.1 mmol of Zn(CH3COO)2 and stirred at room temperature. The mixture was transferred to a Teflon-lined autoclave and heated at 100 °C for 12 h. Washed with ethanol and deionized water in turn, the orange Zn-PTC solid product was collected by centrifugation. Zn-PTC powder was added to deionized water and ultrasonically stirred until a uniform suspension was formed. The Zn-PTC content in the suspension was 0.5 mg / mL.

[0028] S2. A 0.25 wt% CHIT solution was prepared by the following method: 0.25 g chitosan was dissolved in 100 mL 1% acetic acid solution to prepare a chitosan solution, which was vigorously stirred at room temperature and stored at low temperature for later use.

[0029] The preparation method of S3.Ppy-MIP / CHIT / Zn-PTC / GCE molecular imprinting electrochemiluminescence sensor includes the following steps: polishing the glassy carbon electrode, ultrasonicating with nitric acid, anhydrous ethanol and deionized water in turn, dropping 5.0 μL of Zn-PTC suspension on the surface of the glassy carbon electrode, and drying under an infrared lamp to obtain Zn-PTC / GCE; then dropping 5.0 μL of 0.25wt% CHIT solution on the surface of Zn-PTC / GCE, and drying at room temperature to obtain CHIT / Zn-PTC / GCE; placing the prepared CHIT / Zn-PTC / GCE in a phosphate buffered saline (PBS) containing pyrrole (Py) monomer and ENR, and in a traditional three-electrode system, in the presence of 1.0 mmol / LENR and 5.0 mmol / LPy, by cyclic voltammetry (CV), in the range of 0 to 1.2 V, Py is electropolymerized to the surface of CHIT / Zn-PTC / GCE, the number of polymerization cycles is 15 cycles, and the pH of the polymer electrolyte is 2.5. 7.0. ENR is connected to Py through hydrogen bonds and doped in the polypyrrole (Ppy) film to prepare Ppy-MIP-ENR / CHIT / Zn-PTC / GCE. Ppy-MIP-ENR / CHIT / Zn-PTC / GCE is placed in a NaOH: ethanol solution (v:v=3:1) and soaked for a period of time to elute the ENR doped in the Ppy film. The NaOH concentration is 0.1 mol / L, and the soaking time in the NaOH: ethanol solution is 15 min to obtain Ppy-MIP / CHIT / Zn-PTC / GCE.

[0030] An application method of a Ppy-MIP / CHIT / Zn-PTC / GCE molecular imprinting electrochemiluminescence sensor:

[0031] With Ppy-MIP / CHIT / Zn-PTC / GCE as the working electrode, Pt electrode as the auxiliary electrode, and Ag / AgCl as the reference electrode, the ECL signal of Ppy-MIP / CHIT / Zn-PTC / GCE was detected in 0.1 mol / L PBS buffer containing 0.05 mol / L K2S2O8 under the traditional three-electrode system.

[0032] As a preferred embodiment of the above technical solution, the specific steps are as follows:

[0033] A1. PBS contains 0.05 mol / L K2S2O8, the pH of PBS buffer solution is 7.4, and its concentration is 0.1 mol / L.

[0034] A2. Accurately weigh a certain amount of ENR and prepare 1.0×10 -4 mol / L solution, a certain amount of ENR solution was added into PBS containing 0.1 mol / L pH 7.4 to obtain a series of ENR standard solutions with different concentrations, ranging from 1.0×10 - 12 mol / L~1.0×10 -4 mol / L.

[0035] A3. Ppy-MIP / CHIT / Zn-PTC / GCE was used as the working electrode, platinum electrode as the auxiliary electrode, and Ag / AgCl as the reference electrode. In the electrochemical window range of -1.7 to 0 V, the photomultiplier tube high voltage was 800 V, the scan rate was 0.1 V / s, and cyclic voltammetry was performed to record the time-luminescence intensity curve (T-ECL). The ECL intensity of the sensor was detected in PBS containing different concentrations of ENR, and the linear relationship between the ECL intensity and the logarithm of the ENR concentration was established to obtain the corresponding linear regression equation.

[0036] Comparative Example 1: A preparation method and application method of a Ppy-MIP / GCE molecular imprinting electrochemiluminescence sensor.

[0037] A preparation method of Ppy-MIP / GCE molecular imprinting electrochemiluminescence sensor:

[0038] The preparation method of the Ppy-MIP / CHIT / Zn-PTC / GCE molecular imprinting electrochemiluminescence sensor includes the following steps: polishing a glassy carbon electrode, ultrasonicating with nitric acid, anhydrous ethanol and deionized water in sequence, placing the GCE in a phosphate buffer solution (PBS) containing pyrrole (Py) monomer and ENR, and in a traditional three-electrode system, in the presence of 1.0mmol / L ENR and 5.0mmol / L Py, by cyclic voltammetry (CV), in the range of 0 to 1.2V, electropolymerizing Py to the surface of the GCE, the number of polymerization cycles is 15, and the pH of the polyelectrolyte is 7.0. Among them, ENR is connected to Py through hydrogen bonds formed between Py and is doped in the polypyrrole (Ppy) film to prepare Ppy-MIP-ENR / GCE. Ppy-MIP-ENR / GCE was immersed in a NaOH:ethanol solution (v:v=3:1) for a period of time to elute the ENR doped in the Ppy membrane. The NaOH concentration was 0.1 mol / L, and the immersion time in the NaOH:ethanol solution was 15 min to obtain Ppy-MIP / GCE.

[0039] A preparation method of Ppy-MIP / GCE molecular imprinting electrochemiluminescence sensor:

[0040] Ppy-MIP / GCE was used as the working electrode, platinum electrode as the auxiliary electrode, and Ag / AgCl as the reference electrode. The ECL signal of Ppy-MIP / GCE was detected in 0.1 mol / L PBS buffer containing 0.05 mol / L K2S2O8 under the traditional three-electrode system.

[0041] As a preferred embodiment of the above technical solution, the specific steps are as follows:

[0042] A1. PBS contains 0.05 mol / L K2S2O8, the pH of PBS buffer solution is 7.4, and its concentration is 0.1 mol / L.

[0043] A2. Accurately weigh a certain amount of ENR and prepare 1.0×10 -4 mol / L solution, a certain amount of ENR solution was added into PBS containing 0.1 mol / L pH 7.4 to obtain a series of ENR standard solutions with different concentrations, ranging from 1.0×10 - 12 mol / L~1.0×10 -4 mol / L.

[0044] A3. Using Ppy-MIP / GCE as the working electrode, platinum electrode as the auxiliary electrode, and Ag / AgCl as the reference electrode, cyclic voltammetry was performed in the electrochemical window range of -1.7 to 0 V, with a photomultiplier tube high voltage of 800 V and a scan rate of 0.1 V / s, and the time-luminescence intensity curve (T-ECL) was recorded.

[0045] Comparative Example 2: Preparation and application of a CHIT / Zn-PTC / GCE molecular imprinted electrochemiluminescence sensor:

[0046] A preparation method of CHIT / Zn-PTC / GCE molecular imprinted electrochemiluminescence sensor:

[0047] S1. Zn-PTC was obtained by the following method: 1 mmol of perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) and 5 mmol of KOH were dissolved in 4 mL of deionized water by ultrasound and stirred at 60 °C for 10 h. 30 mL of anhydrous ethanol was added to the above solution to obtain golden K4PTC. Subsequently, 0.05 mmol of K4PTC was slowly added to 15 mL of deionized water containing 0.1 mmol of Zn(CH3COO)2 and stirred at room temperature. The mixture was transferred to a Teflon-lined autoclave and heated at 100 °C for 12 h. Washed with ethanol and deionized water in turn, the orange Zn-PTC solid product was collected by centrifugation. Zn-PTC powder was added to deionized water and ultrasonically stirred until a uniform suspension was formed. The Zn-PTC content in the suspension was 0.5 mg / mL.

[0048] S2. A 0.25 wt% CHIT solution was prepared by the following method: 0.25 g chitosan was dissolved in 100 mL 1% acetic acid solution to prepare a chitosan solution, which was vigorously stirred at room temperature and stored at low temperature for later use.

[0049] S3. The preparation method of CHIT / Zn-PTC / GCE molecular imprinting electrochemiluminescence sensor includes the following steps: polishing the glassy carbon electrode, ultrasonicating with nitric acid, anhydrous ethanol and deionized water in turn, dropping 5.0 μL of Zn-PTC suspension on the surface of the glassy carbon electrode, and drying under an infrared lamp to obtain Zn-PTC / GCE; then dropping 5.0 μL of 0.25 wt% CHIT solution on the surface of Zn-PTC / GCE, and drying at room temperature to obtain CHIT / Zn-PTC / GCE

[0050] An application method of a CHIT / Zn-PTC / GCE molecular imprinted electrochemiluminescence sensor:

[0051] With CHIT / Zn-PTC / GCE as the working electrode, Pt electrode as the auxiliary electrode, and Ag / AgCl as the reference electrode, the ECL signal of CHIT / Zn-PTC / GCE was detected in 0.1 mol / L PBS buffer containing 0.05 mol / L K2S2O8 under the traditional three-electrode system.

[0052] As a preferred embodiment of the above technical solution, the specific steps are as follows:

[0053] A1. PBS contains 0.05 mol / L K2S2O8, the pH of PBS buffer solution is 7.4, and its concentration is 0.1 mol / L.

[0054] A2. Accurately weigh a certain amount of ENR and prepare 1.0×10 -4 mol / L solution, a certain amount of ENR solution was added into PBS containing 0.1 mol / L pH 7.4 to obtain a series of ENR standard solutions with different concentrations, ranging from 1.0×10 - 12 mol / L~1.0×10 -4 mol / L.

[0055] A3. With CHIT / Zn-PTC / GCE as the working electrode, platinum electrode as the auxiliary electrode, and Ag / AgCl as the reference electrode, cyclic voltammetry was performed in the electrochemical window range of -1.7 to 0 V, with a photomultiplier tube high voltage of 800 V and a scan rate of 0.1 V / s, and the time-luminescence intensity curve (T-ECL) was recorded.

[0056] Table 1 Determination results of enrofloxacin

[0057]

[0058]

[0059] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A Ppy-MIP / CHIT / Zn-PTC / GCE molecular imprinting electrochemiluminescence sensor for the detection of ENR, characterized in that: The invention comprises a glassy carbon electrode, a Zn-PTC layer, an electrochemically active CHIT layer, and a polypyrrole layer having a cavity with specific imprints of the ENR to be tested, which are sequentially modified on the surface of the glassy carbon electrode from the inside to the outside; The preparation method of Zn-PTC comprises the following steps: slowly adding K4PTC into an aqueous solution of Zn(CH3COO)2 and stirring at room temperature, and transferring the mixture into an autoclave lined with Teflon, heating for reaction, washing with ethanol and deionized water in sequence after the reaction, and collecting an orange Zn-PTC solid product by centrifugation; The preparation method of the Ppy-MIP / CHIT / Zn-PTC / GCE molecular imprinting electrochemiluminescence sensor includes: polishing a glassy carbon electrode, ultrasonicating with nitric acid, anhydrous ethanol and deionized water in sequence, dropping a Zn-PTC suspension on the surface of the glassy carbon electrode, and drying under an infrared lamp to obtain Zn-PTC / GCE; then dropping an acetic acid solution of CHIT on the surface of Zn-PTC / GCE, and drying at room temperature to obtain CHIT / Zn-PTC / GCE; placing the prepared CHIT / Zn-PTC / GCE in a phosphate buffer containing Py monomer and ENR In a three-electrode system, Py was electropolymerized to the surface of CHIT / Zn-PTC / GCE by cyclic voltammetry to generate a Ppy film; wherein ENR was connected with Ppy through hydrogen bonds formed and doped into Ppy to obtain Ppy-MIP-ENR / CHIT / Zn-PTC / GCE; Ppy-MIP-ENR / CHIT / Zn-PTC / GCE was immersed in a NaOH:ethanol solution to elute the ENR doped into the Ppy film to obtain a Ppy-MIP / CHIT / Zn-PTC / GCE molecular imprinting electrochemiluminescence sensor.

2. The Ppy-MIP / CHIT / Zn-PTC / GCE molecular imprinting electrochemiluminescence sensor according to claim 1, characterized in that: The molar ratio of K4PTC to Zn(CH3COO)2 is 1:2, and the amount of K4PTC added is 0.05 mmol; the concentration of the aqueous solution of Zn(CH3COO)2 is 0.1 mmol / mL, the volume is 15 ml, and the stirring time at room temperature is 12 h; the reaction temperature in the autoclave is 100 °C, and the reaction time is 12 h.

3. The method for preparing the Ppy-MIP / CHIT / Zn-PTC / GCE molecular imprinted electrochemiluminescence sensor according to claim 1 or 2, characterized in that: The method comprises the following steps: polishing a glassy carbon electrode, ultrasonicating with nitric acid, anhydrous ethanol and deionized water in sequence, dropping a Zn-PTC suspension on the surface of the glassy carbon electrode, and drying under an infrared lamp to obtain a Zn-PTC / GCE; then dropping an acetic acid solution of CHIT on the surface of the Zn-PTC / GCE, and drying at room temperature to obtain a CHIT / Zn-PTC / GCE; placing the prepared CHIT / Zn-PTC / GCE in a phosphate buffer containing a Py monomer and ENR, and cyclic voltammetry is used to convert Py into ENR in a three-electrode system. Electropolymerization was performed on the surface of CHIT / Zn-PTC / GCE to generate a Ppy film; wherein ENR was connected to Ppy through hydrogen bonds formed between Ppy and doped in Ppy to obtain Ppy-MIP-ENR / CHIT / Zn-PTC / GCE; Ppy-MIP-ENR / CHIT / Zn-PTC / GCE was immersed in a NaOH:ethanol solution to elute the ENR doped in the Ppy film to obtain a Ppy-MIP / CHIT / Zn-PTC / GCE molecular imprinting electrochemiluminescence sensor.

4. The method for preparing the Ppy-MIP / CHIT / Zn-PTC / GCE molecular imprinted electrochemiluminescence sensor according to claim 3, characterized in that: The CHIT concentration in the acetic acid solution of CHIT is 0.25 wt%; the acetic acid concentration is 1.0 wt%.

5. The method for preparing the Ppy-MIP / CHIT / Zn-PTC / GCE molecular imprinted electrochemiluminescence sensor according to claim 3, characterized in that: The conditions for Py electropolymerization were as follows: potential range: 0 ~ 1.2 V; number of scans: 15; Electrolyte: PBS buffer containing Py and ENR, pH 7.0; And / or, a mixed solution of NaOH and ethanol was used as the eluent of ENR, the volume ratio of the two was 3:1, the NaOH concentration was 0.1 mol / L, and the soaking and elution time was 15 min.

6. The method for preparing the Ppy-MIP / CHIT / Zn-PTC / GCE molecular imprinted electrochemiluminescence sensor according to claim 3, characterized in that: The preparation method of Zn-PTC suspension is as follows: Zn-PTC powder is added to deionized water and ultrasonically stirred until a uniform suspension is formed, the Zn-PTC content in the suspension is 0.5 mg / mL, and the modification amount is 5.0 μL; And / or, the modified volume of CHIT solution is 5.0 μL.

7. The method for detecting ENR samples using the Ppy-MIP / CHIT / Zn-PTC / GCE molecular imprinting electrochemiluminescence sensor according to claim 1 or 2, characterized in that: The method comprises the following steps: (1) preparing a phosphate buffer solution and PBS containing potassium persulfate; (2) preparing PBS containing different concentrations of ENR; and (3) drawing a standard curve and determining a linear equation.

8. The method for detecting ENR using a Ppy-MIP / CHIT / Zn-PTC / GCE molecular imprinting electrochemiluminescence sensor according to claim 7, characterized in that: The PBS in step (1) contains 0.05 mol / L K2S2O8, the pH of the PBS buffer solution is 7.4, and its concentration is 0.1 mol / L; And / or, in step (2), accurately weigh a certain amount of ENR and prepare 1.0×10 -4 mol / L solution, a certain amount of ENR solution was added into PBS containing 0.1 mol / L pH7.4 to obtain a series of ENR standard solutions with different concentrations, ranging from 1.0×10 -12 mol / L~1.0×10 -4 mol / L; And / or, in step (3), Ppy-MIP / CHIT / Zn-PTC / GCE is used as the working electrode, the platinum electrode is used as the auxiliary electrode, and the Ag / AgCl electrode is used as the reference electrode. In the electrochemical window range of -1.7 to 0 V, the photomultiplier tube high voltage is 800 V, and the scan rate is 0.1 V / s. Cyclic voltammetry is performed, and the time-luminescence intensity curve is recorded. The ECL intensity of the sensor is detected in PBS containing different concentrations of ENR, and a linear relationship between the ECL intensity and the logarithm of the ENR concentration is established to obtain the corresponding linear regression equation.

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