Electrode and sensor for rapid detection of tyrosine and application thereof

Abstract

This invention provides an electrode with high luminous efficiency, which is prepared by the following method: S1. Synthesizing a Ce2Sn2O7 compound with a pyrochlore structure; S2. Preparing the Ce2Sn2O7 compound obtained in step S1 into a Ce2Sn2O7 / GCE electrode; S3. Preparing the Ce2Sn2O7 / GCE electrode obtained in step S2 into a MIP electrode. Furthermore, this invention also provides a sensor for rapid detection of tyrosine, which is based on Ce2Sn2O7-S2O8. 2‑ / Ru(bpy)3 2+ A RECL-MIP sensing system was constructed using TPrA, with the cathode of the sensing system being the aforementioned electrode with high luminous efficiency. This sensor can be applied to the determination of tyrosine in food. The sensor exhibits superior specificity, sensitivity, stability, and reproducibility for tyrosine, thereby improving food safety assurance.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical technology, specifically relating to an electrode and a sensor for rapid detection of tyrosine and its applications. Background Technology

[0002] Tyrosine (L-tyrosine, Tyr) is an essential amino acid that plays a vital role in the metabolism, growth, and development of humans and animals. It is widely used in the pharmaceutical, food, feed, and chemical industries, and is often used as a nutritional supplement for patients with phenylketonuria (PKU). While humans generally obtain tyrosine through food, the tyrosine content in food varies and is significantly affected by the quality of the food itself. Therefore, there is a need for an accurate, convenient, and rapid method to determine the tyrosine content in food, allowing for control over the total tyrosine intake of the human body, especially patients, thereby improving food safety assurance for daily life and patients. Molecularly imprinted electrochemical sensors can selectively identify and detect specific target compounds. Due to their simple design, rapid detection, high sensitivity, low cost, portability, and ease of miniaturization and automation, they are attracting increasing attention in clinical diagnostics, environmental monitoring, and food analysis. Therefore, developing a molecularly imprinted electrochemical sensor that can accurately, conveniently, and rapidly determine the tyrosine content in food has become a key research focus in the field of molecularly imprinted electrochemical sensors. Summary of the Invention

[0003] One objective of this invention is to provide an electrode that can be used to fabricate molecularly imprinted electrochemical sensors. This electrode is prepared by the following method:

[0004] S1. Synthesize Ce2Sn2O7 compounds with a pyrochlore structure.

[0005] S2. Prepare the Ce2Sn2O7 compound obtained in step S1 as a Ce2Sn2O7 / GCE electrode.

[0006] S3. The Ce2Sn2O7 / GCE electrode obtained in step S2 is prepared as a MIP electrode.

[0007] Furthermore, the method for synthesizing the Ce2Sn2O7 compound with a pyrochlore structure described in step S1 includes:

[0008] First, Ce(NO3)3·6H2O and SnCl2·2H2O were dissolved in V mL of deionized water to obtain a mixed solution.

[0009] Then, 0.1-0.15 mL of saturated sodium hydroxide aqueous solution was added to the mixture, and the solution was stirred thoroughly to obtain the alkaline treatment solution.

[0010] The alkaline treatment solution was then transferred to a polytetrafluoroethylene dispersion and heated at 160-180℃ for 20-28 hours to obtain a heated solution.

[0011] Then, after solid-liquid separation of the heated solution, the solid phase component was washed with distilled water and ethanol to obtain solid phase component A.

[0012] Finally, solid component A was dried at 55-65℃ for 10-18h to obtain Ce2Sn2O7 compound with pyrochlore structure.

[0013] Furthermore, the molar concentration of the mixture solution is 0.1-0.15 mol / L. The amounts of Ce(NO3)3·6H2O and SnCl2·2H2O added satisfy the following conditions: Ce... 3+ and Sn 2+ The molar concentration ratio of Ce is 3+ Sn 2+ =1:0.8-1.5.

[0014] Furthermore, the method for preparing the Ce2Sn2O7 compound obtained in step S1 into a Ce2Sn2O7 / GCE electrode as described in step S2 includes:

[0015] First, the GCE is polished to a mirror finish using 0.02-0.05μM alumina powder to obtain polished GCE.

[0016] Then, the polished GCE was ultrasonically treated sequentially with nitric acid aqueous solution, ethanol aqueous solution and ultrapure water, with each ultrasonic treatment lasting 3-7 minutes.

[0017] Subsequently, the Ce2Sn2O7 compound with the pyrochlore structure obtained in step S1 was taken and prepared as a Ce2Sn2O7 suspension at a concentration of 0.8-1.2 mg / mL.

[0018] Finally, after the ultrasonically treated polished GCE has dried naturally, a Ce2Sn2O7 suspension is dropped onto the surface of the polished GCE and dried to obtain the Ce2Sn2O7 / GCE electrode.

[0019] Furthermore, the nitric acid aqueous solution is prepared by mixing fuming nitric acid and water in a volume ratio of fuming nitric acid:water = 1:0.8-1.5. The ethanol aqueous solution is prepared by mixing anhydrous ethanol and water in a volume ratio of anhydrous ethanol:water = 1:0.8-1.5.

[0020] Furthermore, the diameter of the GCE is 2-5 mm, and the amount of Ce2Sn2O7 suspension added is 3-8 μL.

[0021] Furthermore, the method for preparing the Ce2Sn2O7 / GCE electrode obtained in step S2 into a MIP electrode, as described in step S3, is as follows:

[0022] First, the Ce2Sn2O7 / GCE electrode obtained in step S2 is placed in a phosphate buffer solution containing pyridine and tyrosine to obtain the Ce2Sn2O7 / GCE electrode buffer solution.

[0023] Then, the Ce2Sn2O7 / GCE electrode buffer was cycled 6-10 times using cyclic voltammetry at a scan rate of 90mV / s within a voltage range of -0.2 to 0.8V to obtain the Ce2Sn2O7 / MIP / GCE electrode.

[0024] Finally, the Ce2Sn2O7 / MIP / GCE electrode was immersed in a methanol aqueous solution and stirred for 10-20 min, then washed with water and dried at room temperature to obtain the MIP electrode.

[0025] Furthermore, the concentration of the phosphate buffered saline is 0.08-0.12 mol / L. The concentration of pyridine in the phosphate buffered saline is 8-12 mmol / L. The concentration of tyrosine in the phosphate buffered saline is 3-3.5 mmol / L. The methanol-water mixture is prepared by mixing methanol and water at a volume ratio of methanol:water = 1:0.8-1.5.

[0026] The second objective of this invention is to provide a sensor for the rapid detection of tyrosine, which is based on Ce2Sn2O7-S2O8. 2- / Ru(bpy)3 2+ The RECL-MIP sensing system is constructed using TPrA, wherein the cathode of the sensing system is the electrode described above.

[0027] The third objective of this invention is to provide an application of a sensor for rapid detection of tyrosine: applying the aforementioned RECL-MIP sensor for rapid detection of tyrosine to the determination of tyrosine in food.

[0028] In this invention:

[0029] GCE refers to glassy carbon electrode;

[0030] Tyr refers to tyrosine;

[0031] PBS stands for phosphate-buffered saline.

[0032] CV refers to cyclic voltammetry;

[0033] Ru(bpy)3 2+ Refers to metal polypyridine photocatalysts;

[0034] TPrA refers to tripropylamine.

[0035] This invention has at least one of the following advantages:

[0036] 1. This invention synthesizes a Ce2Sn2O7 electrode with high luminous efficiency through a simple method.

[0037] 2. This invention combines a Ce2Sn2O7 cathode with high luminous efficiency with Ru(bpy)3. 2+ Ce2Sn2O7-S2O8 was constructed 2- / Ru(bpy)3 2+ The RECL-MIP sensor of the -TPrA system exhibits superior specificity and extremely high sensitivity for tyrosine, along with excellent stability and reproducibility. Attached Figure Description

[0038] Figure 1 The image shown is a SEM image of Ce2Sn2O7 obtained in Example 1 of the present invention.

[0039] Figure 2 The image shown is a TEM image of Ce2Sn2O7 obtained in Example 1 of the present invention.

[0040] Figure 3 The image shown is a high-resolution transmission electron microscope image of Ce2Sn2O7 obtained in Example 1 of the present invention.

[0041] Figure 4 The image shown is the XRD pattern of CeO2.

[0042] Figure 5 The image shown is the XRD pattern of SnO2.

[0043] Figure 6 The image shown is the XRD pattern of Ce2Sn2O7 obtained in Example 1 of the present invention.

[0044] Figure 7 The X-ray photoelectron spectrum of Ce2Sn2O7 obtained in Example 1 of the present invention is shown.

[0045] Figure 8 The image shows the ECL results for CeO2 and SnO2.

[0046] Figure 9 The figure shown is an ECL result diagram of Ce2Sn2O7 of the present invention.

[0047] Figure 10 The figure shown is a test result diagram based on RECL and cyclic voltammetry.

[0048] Figure 11The figure shows the ECL intensity and CV test results of the RECL-MIP sensor of this invention using Tyr as the template molecule.

[0049] Figure 12 The figure shown is a linear regression diagram of the anode ECL-Tyr concentration in the sensor system of Ce2Sn2O7-S2O82- / Ru(bpy)32+-TPrA of the present invention.

[0050] Figure 13 The figure shown is a linear regression diagram of the cathode ECL-Tyr concentration in the sensor system of Ce2Sn2O7-S2O82- / Ru(bpy)32+-TPrA of the present invention.

[0051] Figure 14 The figure shown is a linear regression diagram of the anode-cathode ratio (Ia / Ic) and Tyr concentration for the sensor system of Ce2Sn2O7-S2O82- / Ru(bpy)32+-TPrA of the present invention. Detailed Implementation

[0052] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of the invention.

[0053] Example 1

[0054] An electrode that can be used to fabricate a molecularly imprinted electrochemical sensor. This high-luminescence-efficiency electrode is prepared by the following method:

[0055] S1. Synthesize Ce2Sn2O7 compounds with a pyrochlore structure.

[0056] S2. Prepare the Ce2Sn2O7 compound obtained in step S1 as a Ce2Sn2O7 / GCE electrode.

[0057] S3. The Ce2Sn2O7 / GCE electrode obtained in step S2 is prepared as a MIP electrode.

[0058] The method for synthesizing the Ce2Sn2O7 compound with a pyrochlore structure described in step S1 includes:

[0059] First, Ce(NO3)3·6H2O and SnCl2·2H2O were dissolved in V mL of deionized water to obtain a mixture solution. The molar concentration of the mixture solution was 0.125 mol / L. The amount of Ce(NO3)3·6H2O and SnCl2·2H2O added met the following conditions: Ce... 3+ and Sn 2+ The molar concentration ratio of Ce is 3+ Sn2+ =1:1.

[0060] Then, 0.125 mL of saturated sodium hydroxide aqueous solution was added to the mixture, and the solution was stirred thoroughly to obtain the alkaline treatment solution.

[0061] The alkaline treatment solution was then transferred to a polytetrafluoroethylene dispersion and heated at 170°C for 24 hours to obtain a heated solution.

[0062] Then, after solid-liquid separation of the heated solution, the solid phase component was washed with distilled water and ethanol to obtain solid phase component A.

[0063] Finally, solid component A was dried at 60 °C for 12 h to obtain Ce2Sn2O7 compound with pyrochlore structure.

[0064] The method for preparing the Ce2Sn2O7 compound obtained in step S1 into a Ce2Sn2O7 / GCE electrode as described in step S2 includes:

[0065] First, the GCE was polished to a mirror finish using 0.03 μM alumina powder to obtain a polished GCE. The diameter of the GCE was 3 mm.

[0066] Then, the polished GCE was ultrasonically treated sequentially with nitric acid aqueous solution, ethanol aqueous solution, and ultrapure water, with each ultrasonic treatment lasting 5 minutes. The nitric acid aqueous solution was prepared by mixing fuming nitric acid and water in a volume ratio of fuming nitric acid:water = 1:1. The ethanol aqueous solution was prepared by mixing anhydrous ethanol and water in a volume ratio of anhydrous ethanol:water = 1:1.

[0067] Subsequently, the Ce2Sn2O7 compound with the pyrochlore structure obtained in step S1 was taken and prepared as a Ce2Sn2O7 suspension at a concentration of 1 mg / mL.

[0068] Finally, after the ultrasonically treated polished GCE has dried naturally, a Ce2Sn2O7 suspension is dropped onto the polished GCE surface, and after drying, the Ce2Sn2O7 / GCE electrode is obtained. The amount of Ce2Sn2O7 suspension added is 5 μL.

[0069] The method for preparing the Ce2Sn2O7 / GCE electrode obtained in step S2 as a MIP electrode, as described in step S3, is as follows:

[0070] First, the Ce2Sn2O7 / GCE electrode obtained in step S2 is immersed in a phosphate buffer solution containing pyridine and tyrosine to obtain the Ce2Sn2O7 / GCE electrode buffer solution. The concentration of the phosphate buffer solution is 0.1 mol / L. The concentration of pyridine in the phosphate buffer solution is 10 mmol / L. The concentration of tyrosine in the phosphate buffer solution is 3.3 mmol / L.

[0071] Then, the Ce2Sn2O7 / GCE electrode buffer was cycled 8 times using cyclic voltammetry at a scan rate of 90mV / s within a voltage range of -0.2 to 0.8V to obtain the Ce2Sn2O7 / MIP / GCE electrode.

[0072] Finally, the Ce2Sn2O7 / MIP / GCE electrode was immersed in a methanol-water solution and stirred for 15 minutes, then washed with water and dried at room temperature to obtain the MIP electrode. The methanol-water solution was prepared by mixing methanol and water in a volume ratio of methanol:water = 1:1.

[0073] Example 2

[0074] An electrode that can be used to fabricate a molecularly imprinted electrochemical sensor. This high-luminescence-efficiency electrode is prepared by the following method:

[0075] S1. Synthesize Ce2Sn2O7 compounds with a pyrochlore structure.

[0076] S2. Prepare the Ce2Sn2O7 compound obtained in step S1 as a Ce2Sn2O7 / GCE electrode.

[0077] S3. The Ce2Sn2O7 / GCE electrode obtained in step S2 is prepared as a MIP electrode.

[0078] The method for synthesizing the Ce2Sn2O7 compound with a pyrochlore structure described in step S1 includes:

[0079] First, Ce(NO3)3·6H2O and SnCl2·2H2O were dissolved in V mL of deionized water to obtain a mixture solution. The molar concentration of the mixture solution was 0.15 mol / L. The amount of Ce(NO3)3·6H2O and SnCl2·2H2O added met the following conditions: Ce... 3+ and Sn 2+ The molar concentration ratio of Ce is 3+ Sn 2+ = 1:1.5.

[0080] Then, 0.15 mL of saturated sodium hydroxide aqueous solution was added to the mixture, and the solution was stirred thoroughly to obtain the alkaline treatment solution.

[0081] The alkaline treatment solution was then transferred to a polytetrafluoroethylene dispersion and heated at 180°C for 28 hours to obtain a heated solution.

[0082] Then, after solid-liquid separation of the heated solution, the solid phase component was washed with distilled water and ethanol to obtain solid phase component A.

[0083] Finally, solid component A was dried at 65 °C for 18 h to obtain Ce2Sn2O7 compound with pyrochlore structure.

[0084] The method for preparing the Ce2Sn2O7 compound obtained in step S1 into a Ce2Sn2O7 / GCE electrode as described in step S2 includes:

[0085] First, the GCE was polished to a mirror finish using 0.05 μM alumina powder to obtain a polished GCE. The diameter of the GCE was 5 mm.

[0086] Then, the polished GCE was ultrasonically treated sequentially with nitric acid aqueous solution, ethanol aqueous solution, and ultrapure water, with each ultrasonic treatment lasting 7 minutes. The nitric acid aqueous solution was prepared by mixing fuming nitric acid and water in a volume ratio of fuming nitric acid:water = 1:1.5. The ethanol aqueous solution was prepared by mixing anhydrous ethanol and water in a volume ratio of anhydrous ethanol:water = 1:1.5.

[0087] Subsequently, the Ce2Sn2O7 compound with the pyrochlore structure obtained in step S1 was taken and prepared as a Ce2Sn2O7 suspension at a concentration of 1.2 mg / mL.

[0088] Finally, after the ultrasonically treated polished GCE has dried naturally, a Ce2Sn2O7 suspension is dropped onto the polished GCE surface, and after drying, the Ce2Sn2O7 / GCE electrode is obtained. The amount of Ce2Sn2O7 suspension added is 8 μL.

[0089] The method for preparing the Ce2Sn2O7 / GCE electrode obtained in step S2 as a MIP electrode, as described in step S3, is as follows:

[0090] First, the Ce2Sn2O7 / GCE electrode obtained in step S2 is immersed in a phosphate buffer solution containing pyridine and tyrosine to obtain the Ce2Sn2O7 / GCE electrode buffer solution. The concentration of the phosphate buffer solution is 0.12 mol / L. The concentration of pyridine in the phosphate buffer solution is 12 mmol / L. The concentration of tyrosine in the phosphate buffer solution is 3.5 mmol / L.

[0091] Then, the Ce2Sn2O7 / GCE electrode buffer was cycled 10 times using cyclic voltammetry at a scan rate of 90 mV / s within a voltage range of -0.2 to 0.8 V to obtain the Ce2Sn2O7 / MIP / GCE electrode.

[0092] Finally, the Ce2Sn2O7 / MIP / GCE electrode was immersed in a methanol-water solution and stirred for 20 minutes, then washed with water and dried at room temperature to obtain the MIP electrode. The methanol-water solution was prepared by mixing methanol and water in a volume ratio of methanol:water = 1:1.5.

[0093] Example 3

[0094] An electrode that can be used to fabricate a molecularly imprinted electrochemical sensor. This high-luminescence-efficiency electrode is prepared by the following method:

[0095] S1. Synthesize Ce2Sn2O7 compounds with a pyrochlore structure.

[0096] S2. Prepare the Ce2Sn2O7 compound obtained in step S1 as a Ce2Sn2O7 / GCE electrode.

[0097] S3. The Ce2Sn2O7 / GCE electrode obtained in step S2 is prepared as a MIP electrode.

[0098] The method for synthesizing the Ce2Sn2O7 compound with a pyrochlore structure described in step S1 includes:

[0099] First, Ce(NO3)3·6H2O and SnCl2·2H2O were dissolved in V mL of deionized water to obtain a mixture solution. The molar concentration of the mixture solution was 0.1 mol / L. The amounts of Ce(NO3)3·6H2O and SnCl2·2H2O added met the following conditions: Ce... 3+ and Sn 2+ The molar concentration ratio of Ce is 3+ Sn 2+ =1:0.8.

[0100] Then, 0.1 mL of saturated sodium hydroxide aqueous solution was added to the mixture, and the solution was stirred thoroughly to obtain the alkaline treatment solution.

[0101] The alkaline treatment solution was then transferred to a polytetrafluoroethylene dispersion and heated at 160°C for 20 hours to obtain a heated solution.

[0102] Then, after solid-liquid separation of the heated solution, the solid phase component was washed with distilled water and ethanol to obtain solid phase component A.

[0103] Finally, solid component A was dried at 55 °C for 10 h to obtain Ce2Sn2O7 compound with pyrochlore structure.

[0104] The method for preparing the Ce2Sn2O7 compound obtained in step S1 into a Ce2Sn2O7 / GCE electrode as described in step S2 includes:

[0105] First, the GCE was polished to a mirror finish using 0.02 μM alumina powder to obtain a polished GCE. The diameter of the GCE was 2 mm.

[0106] Then, the polished GCE was ultrasonically treated sequentially with nitric acid aqueous solution, ethanol aqueous solution, and ultrapure water, with each ultrasonic treatment lasting 3 minutes. The nitric acid aqueous solution was prepared by mixing fuming nitric acid and water in a volume ratio of fuming nitric acid:water = 1:0.8. The ethanol aqueous solution was prepared by mixing anhydrous ethanol and water in a volume ratio of anhydrous ethanol:water = 1:0.8.

[0107] Subsequently, the Ce2Sn2O7 compound with the pyrochlore structure obtained in step S1 was taken and prepared as a Ce2Sn2O7 suspension at a concentration of 0.8 mg / mL.

[0108] Finally, after the ultrasonically treated polished GCE has dried naturally, a Ce2Sn2O7 suspension is dropped onto the polished GCE surface, and after drying, the Ce2Sn2O7 / GCE electrode is obtained. The amount of Ce2Sn2O7 suspension added is 3 μL.

[0109] The method for preparing the Ce2Sn2O7 / GCE electrode obtained in step S2 as a MIP electrode, as described in step S3, is as follows:

[0110] First, the Ce2Sn2O7 / GCE electrode obtained in step S2 is immersed in a phosphate buffer solution containing pyridine and tyrosine to obtain the Ce2Sn2O7 / GCE electrode buffer solution. The concentration of the phosphate buffer solution is 0.08 mol / L. The concentration of pyridine in the phosphate buffer solution is 8 mmol / L. The concentration of tyrosine in the phosphate buffer solution is 3 mmol / L.

[0111] Then, the Ce2Sn2O7 / GCE electrode buffer was cycled 6 times using cyclic voltammetry at a scan rate of 90 mV / s within a voltage range of -0.2 to 0.8 V to obtain the Ce2Sn2O7 / MIP / GCE electrode.

[0112] Finally, the Ce2Sn2O7 / MIP / GCE electrode was immersed in a methanol-water solution and stirred for 10 minutes, then washed with water and dried at room temperature to obtain the MIP electrode. The methanol-water solution was prepared by mixing methanol and water in a volume ratio of methanol:water = 1:0.8.

[0113] Electrochemical measurements and product performance characterization analyses were performed using the electrode obtained in Example 1.

[0114] The electrochemical measurement method is as follows:

[0115] In a solution containing 5 mmol / L Ru(bpy)3 2+Electrochemiluminescence (ECL) signal intensity was measured using a three-electrode system in 0.1 mol / L PBS (pH = 7.4, total volume 3 mL) containing 50 mmol / L TPrA (tripropylamine). Ce₂Sn₂O₇ / GCE was used as the working electrode, while Ag / AgCl and platinum electrodes served as the reference and auxiliary electrodes, respectively. The scan range was set to -1.8 to +1.2 V, the scan rate to 100 mV / s, and the photomultiplier tube voltage to 800 V.

[0116] Furthermore, CV tests were performed using an electrochemical CV analyzer in a 5.0 mM K3[Fe(CN)6] / K4[Fe(CN)6] solution within the 0.5 M KCl range. The CV test conditions were: scan range of -0.2–0.6 V and scan rate of 90 mV / s. The detection conditions for EIS impedance method were: potential of 0.005 V, frequency of 0.1–100000 Hz, and AC voltage of 0.25 mV.

[0117] The electrochemical testing and characterization results are as follows:

[0118] The morphology and structure of Ce₂Sn₂O₇ obtained in Example 1 were analyzed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It can be seen that, as... Figure 1 As shown, Ce2Sn2O7 synthesized by hydrothermal method exhibits a cubic structure, such as... Figure 2 The TEM images shown also confirm this result. This large surface area cubic structure can promote the adsorption of more matrix, accelerate the transfer of photoelectrons, and is beneficial to improving electrochemical performance. Furthermore, the lattice state of Ce₂Sn₂O₇ was further analyzed using high-resolution transmission electron microscopy (HRTEM). Figure 3 As shown, many different lattices can be observed on the Ce2Sn2O7 surface, with lattice spacings of approximately 0.264 and 0.305 nm, corresponding to the (400) and (222) crystal planes, respectively.

[0119] The crystal structure information was characterized using X-ray diffraction (XRD). For example... Figure 4 As shown, according to PDF#34-0394, the diffraction peaks of CeO2 at 28.02° and 47.51° are attributed to the 111 and 220 crystal planes of CeO2, respectively. Figure 5 As shown, for SnO2, some main peaks at 23.33° and 26.51° correspond to the (111), (101), and (211) crystal planes of SnO2, respectively (PDF#41-1445). Figure 6As shown, strong diffraction peaks were observed in Ce₂Sn₂O₇ obtained in Example 1 at 29.4°, 33.8°, 48.6°, 57.8°, and 60.6°, which can be labeled as (222), (400), (440), (622), and (444) crystal planes. All peaks are consistent with the crystal structure of Ce₂Sn₂O₇ (PDF#48-0648), and no characteristic peaks of other impurities such as SnO₂ and CeO₂ were observed. This indicates that the Ce₂Sn₂O₇ prepared by this invention has a uniform crystal form and crystal structure.

[0120] X-ray photoelectron spectroscopy (XPS) was performed to assess the electronic composition and chemical state of the Ce₂Sn₂O₇ surface to reveal its electron transfer mechanism. The results are as follows: Figure 7 As shown in -A. Figure 7 As shown in -B, the Ce 3d spectrum exhibits two sets of peaks at Ce 3d3 / 2 and Ce 3d5 / 2. The peaks at 897.44 eV and 913.7 eV belong to Ce 3d3 / 2, while the peaks at 883.14 eV and 887.42 eV belong to Ce 3d5 / 2. Furthermore, as... Figure 7 As shown in -C, the characteristic peaks at 486.98 eV and 495.39 eV correspond to Sn 3d5 / 2 and Sn 3d3 / 2, respectively, which are consistent with the Sn4-O bonds known in the prior art. Figure 7 The XPS spectrum of O1S shown in -D has characteristic peaks at 530.82 eV and 531.36 eV, which are assigned to lattice oxygen and oxygen in hydroxyl groups, respectively, while 531.62 eV corresponds to oxygen vacancies (OV).

[0121] The above tests and analyses demonstrate that a Ce2Sn2O7 electrode can be prepared using the method of this invention. The RECL performance and mechanism of this Ce2Sn2O7 electrode are tested and analyzed as follows:

[0122] To characterize the RECL performance of the Ce2Sn2O7 electrode, this invention constructs a Ce2Sn2O7-S2O8-based electrode. 2- / Ru(bpy)3 2+ The RECL system of -TPrA was used to characterize the modification of different materials on the electrode using electrochemical and ECL tests. For example... Figure 8 As shown, in the RECL system, the ECL signals of CeO2 and SnO2 are very low, indicating poor stability of the cathode and anode. Conversely, as Figure 9 As shown, Ce₂Sn₂O₇ exhibits strong and stable signals at -1.8V and +1.2V. This is because Ce₂Sn₂O₇ has a large specific surface area, thereby improving the sensor's sensitivity and photoelectric performance. With the development of Ce₂Sn₂O₇... 3+ / Ce 4+The reversible cycle produces stable SO4. ·- This significantly improves the ECL response. The above results demonstrate that Ce2Sn2O7-S2O8... 2- / Ru(bpy)3 2+ - The RECL of the TPrA system has been successfully established.

[0123] Under optimal conditions, a series of conditional experiments were conducted based on RECL and cyclic voltammetry (CV) response, and the results are as follows: Figure 10 As shown. Figure 10 As shown in -A and 10-B, GCE showed no ECL response only in the PBS environment. However, the weak ECL response was negligible when K2S2O8 or TPrA was added to the above systems, respectively. Similarly, the reaction was very weak when both were mixed. These phenomena further confirm that GCE or the co-reactant itself does not induce a strong ECL reaction. Adding Ru(bpy)3 to the reaction system... 2+ It can generate a strong TprA anode signal, which is similar to Ru(bpy)3. 2+ It is closely related to the redox reaction of TPRA. Meanwhile, Ru(bpy)3 2+ The reaction with K₂S₂O₈ exhibits a weak ECL response at -1.5 eV, which is insufficient for constructing a RECL sensor. Figure 10 As shown in -C and 10-D, the above results indicate that in the reaction system, when the two co-reactants coexist at the anode, they do not interfere with each other. However, to improve the sensitivity of the RECL sensor, Ce2Sn2O7 was modified on the electrode surface, resulting in an ECL response with an intensity of 16000 at -1.8 eV without affecting the anode signal. These results further confirm the presence of two co-reactants (TPrA and K2S2O8) and two luminescent materials (Ru(bpy)3). 2+ The simultaneous presence of Ce₂Sn₂O₇ will produce two strong signal peaks at -1.8 and +1.2 eV, respectively, as shown below. Figure 11 As shown in -A, the corresponding CV also shows a reversible reduction oxidation peak, indicating that the present invention has successfully constructed a Ce2Sn2O7-S2O8-based system. 2- / Ru(bpy)3 2+ -TPrA system of RECL.

[0124] Based on Ce2Sn2O7-S2O8 2- / Ru(bpy)3 2+ In the RECL system of the -TPrA system, the cathode co-reactant is first electrochemically reduced to SO4. ·- It exhibits strong oxidizing properties during negative potential scanning. Simultaneously, Ce₂Sn₂O₇ is also reduced to negatively charged Ce₂Sn₂O₇.·- Continue with SO4 ·- The reaction forms an excited state Ce2Sn2O7 * Finally, Ce2Sn2O7 * Returning from the excited state to the ground and stable states, Ce₂Sn₂O₇ will emit light with an intensity of approximately 16,000 at -1.8V. Furthermore, Ru(bpy)₃ 2+ As a luminescent material, it can be oxidized and reduced. Ru(bpy)3 2+ It is oxidized to Ru(bpy)3 at the anode. 3+ TPrA also undergoes oxidation to form the highly reducing intermediate TPrA˙. Therefore, TPrA˙ and Ru(bpy)3 3+ The reaction between them is activated, thus forming an excited material. Similarly, when the excited substrate returns to its ground state, it emits light at +1.2V. However, in the cathode Ru(bpy)3 3+ It will revert to Ru(bpy)3 + S2O8 2- It will also be reduced to SO4 ·- These two reducing substances further react to form [Ru(bpy)3] 2+ During the return to the ground state, the signal peak value is approximately -1.5V. This clearly explains why there are two signal peaks at the cathode. The reaction equation is as follows:

[0125] S2O8 2- +e - →SO4 2- +SO4 ·-

[0126] Ce2Sn2O7+e - →(Ce2Sn2O7) ·-

[0127] (Ce2Sn2O7) ·- +SO4 ·- →(Ce2Sn2O7) * +SO4 2-

[0128] (Ce2Sn2O7) * →Ce2Sn2O7+hv

[0129] S2O8 2- +e - →SO4 2- +SO4 ·-

[0130] Ru(bpy)3 2+ +SO4·- →Ru(bpy)3 3+ +SO4 2-

[0131] Ru(bpy)3 3+ +e-→[Ru(bpy)3 2+ ]*

[0132] Ru(bpy)3 2+ +e - →Ru(bpy)3 +

[0133] Ru(bpy)3 + +SO4 ·- →[Ru(bpy)3 2+ ]*+SO4 2-

[0134] [Ru(bpy)3 2+ ]*→Ru(bpy)3 2+ +hv

[0135] Ru(bpy)3 2+ -e - →Ru(bpy)3 3+

[0136] TPrA-e - →TPrA ·+

[0137] TPrA ·+ →TPrA·+H +

[0138] Ru(bpy)3 3+ +TPrA·→[Ru(bpy)3 2+ ]*+TPrA

[0139] [Ru(bpy)3 2+ ]*→Ru(bpy)3 2+ +hv.

[0140] Example 4

[0141] A sensor for rapid detection of tyrosine, the sensor being based on Ce2Sn2O7-S2O8 2- / Ru(bpy)3 2+ -TPrA constructs a RECL-MIP sensing system, wherein the cathode of the sensing system is any one of the electrodes in Examples 1-3.

[0142] The testing and performance analysis of the sensor are as follows:

[0143] like Figure 11 As shown in -A and 11-B, using Tyr as the template molecule, when MIP is completed, the poorly conductive film hinders electron transfer, leading to a decrease in the signal intensity of ECL at both the cathode and anode. Removing the template molecule significantly increases the signal intensity, accompanied by a corresponding increase in current. This is because the cavity formed by the template molecule provides a superior channel for electron transfer, accelerating the electrochemical reaction kinetics. Furthermore, the formation of the imprinted cavity was further confirmed by culturing. Meanwhile, as... Figure 11 As shown in -C and 11-D, the ECL intensity and CV response are significantly reduced after recombination of the RECL-MIP system with template molecules, because the template molecules clog the imprint cavity and hinder electron transfer.

[0144] CV and electrochemical impedance spectroscopy (EIS) tests were performed to confirm the successful construction of the RECL-MIP sensing system. Due to its low conductivity, the redox current response of Ce2Sn2O7 / GCE was lower than that of bare GCE. Meanwhile, the peak current of NIPs was significantly better than that of MIPs and the peak current after template molecule removal. This is because electropolymerization forms a dense MIP film, which hinders electron transfer and leads to a decrease in electrochemical reaction kinetics. Conversely, after MIP elution, some imprinted cavities serving as active sites are exposed, allowing redox probes to easily penetrate the material surface through the pores, thereby increasing the CV response. Similarly, the conductivity recovers to near its original state after reabsorption. These results confirm the successful construction of the sensing system.

[0145] Figure 11 The EIS of the sensor platform for each process is shown. The almost linear GCE resistance (Rct) of the bare electrode is observed, indicating that the electron transfer process on the bare electrode surface is diffusion-controlled, resulting in low resistance. The Rct of Ce2Sn2O7 / GCE is also low, possibly because the low conductivity of Ce2Sn2O7 hinders electron transfer. However, the Rct increases significantly with the electropolymerization of the insulating MIP. Conversely, the removal of template molecules creates imprinted cavities, making the redox probe more permeable. Exposing more electrochemically active sites improves reaction kinetics, thus reducing Rct. Subsequently, with the hatching of template molecules, an even higher Rct is generated. This may be related to the non-conductive nature of the template molecules. These results are consistent with CV, demonstrating the successful construction of the RECL-MIP sensor.

[0146] Under optimal conditions, based on Ce2Sn2O7-S2O8 2- / Ru(bpy)3 2+ The RECL-MIP optical signal generated by the -TPrA sensor system decreases with increasing electropolymerized Tyr concentration. The ECL response value shows a linear relationship with the logarithm of the Tyr concentration at both the anode and cathode, as shown below. Figure 12 and Figure 13 As shown. The corresponding linear regression equations are Ia = 2444.4093 - 133.3099logCTry (R2 = 0.9712) and Ic = 2444.9823 - 1425.6455logCTry (R2 = 0.98094).

[0147] To further achieve accurate measurements, ensure data reliability, and improve the specificity and selectivity of the RECL-MIP sensor, this invention proposes a novel ratio dual-signal MIP sensing system to eliminate background interference. (In 1×10...) -8 Up to 1×10 -3 Within the nm range, such as Figure 14 As shown, a good linear relationship was achieved between the ECL anode-to-cathode ratio (Ia / Ic) and the Tyr concentration. A linear regression equation of the logarithm of Tyr, Ia / Ic = 0.50371 + 0.03338, was calculated. Compared with single cathode and single anode, the linear correlation coefficient R²Ia / Ic (R² = 0.99845) > R²Ic > R²Ia, indicating that the RECL-MIP sensor has higher accuracy, specificity, and sensitivity.

[0148] To test the present invention based on Ce2Sn2O7-S2O8 2- / Ru(bpy)3 2+ The stability and reproducibility of the RECL-MIP sensing system constructed with -TPrA are evaluated by using the binding ability of tyrosine analogs (L-tyrosine, dopamine, spermine, levodopa, etc.) to Py to assess the selectivity and specificity of the RECL-MIP sensor.

[0149] In summary, this invention is based on Ce2Sn2O7-S2O8 2- / Ru(bpy)3 2+ The RECL-MIP sensing system constructed with -TPrA can accurately and specifically identify Tyr, and has good sensitivity, stability, and reproducibility. Therefore, it is suitable for the determination of Tyr in food. It also possesses the rapid detection function inherent in RECL-MIP sensors based on color changes. When the RECL-MIP sensor for rapid tyrosine detection of this invention is applied to the rapid detection of tyrosine content in food, it can achieve rapid, accurate, stable, and sensitive determination, thereby significantly improving food safety assurance.

[0150] It should be noted and understood that various modifications and improvements can be made to the invention described in the above detailed description without departing from the spirit and scope of the claims. Therefore, the scope of the claimed solutions is not limited to any specific exemplary teachings given.

Claims

1. An electrode, characterized in that, This electrode was prepared by the following method: S1. Synthesis of Ce2Sn2O7 compounds with a pyrochlore structure; S2. The Ce2Sn2O7 compound obtained in step S1 is used to prepare a Ce2Sn2O7 / GCE electrode, specifically including: First, the GCE is polished to a mirror finish using 0.02-0.05μM alumina powder to obtain polished GCE; Then, the polished GCE was ultrasonically treated sequentially with nitric acid aqueous solution, ethanol aqueous solution and ultrapure water, with each ultrasonic treatment lasting 3-7 minutes. Then, the Ce2Sn2O7 compound with the pyrochlore structure obtained in step S1 was taken and prepared into a Ce2Sn2O7 suspension of 0.8-1.2 mg / mL; Finally, after the ultrasonically treated polished GCE has dried naturally, Ce2Sn2O7 suspension is dropped onto the polished GCE surface and dried to obtain the Ce2Sn2O7 / GCE electrode. S3. The Ce2Sn2O7 / GCE electrode obtained in step S2 is prepared as a MIP electrode, specifically including: First, the Ce2Sn2O7 / GCE electrode obtained in step S2 is immersed in a phosphate buffer solution containing pyridine and tyrosine to obtain the Ce2Sn2O7 / GCE electrode buffer solution. Then, the Ce2Sn2O7 / GCE electrode buffer was cycled 6-10 times using cyclic voltammetry at a scan rate of 90mV / s within a voltage range of -0.2 to 0.8V to obtain the Ce2Sn2O7 / MIP / GCE electrode. Finally, the Ce2Sn2O7 / MIP / GCE electrode was immersed in a methanol aqueous solution and stirred for 10-20 minutes, then washed with water and dried at room temperature to obtain the MIP electrode.

2. The electrode according to claim 1, characterized in that, The method for synthesizing the Ce2Sn2O7 compound with a pyrochlore structure described in step S1 includes: First, dissolve Ce(NO3)3·6H2O and SnCl2·2H2O in V mL of deionized water to obtain a mixed solution; Then, 0.1-0.15 mL of saturated sodium hydroxide aqueous solution was added to the mixture solution, and the solution was stirred thoroughly to obtain the alkaline treatment solution. Then, the alkali-treated solution was transferred to a polytetrafluoroethylene dispersion and heated at 160-180℃ for 20-28 hours to obtain a heated solution. Then, after solid-liquid separation of the heated solution, the solid phase component was washed with distilled water and ethanol to obtain solid phase component A; Finally, solid component A was dried at 55-65℃ for 10-18h to obtain Ce2Sn2O7 compound with pyrochlore structure.

3. The electrode according to claim 2, characterized in that, The molar concentration of the mixture solution is 0.1-0.15 mol / L; wherein the amount of Ce(NO3)3·6H2O and SnCl2·2H2O added satisfies the following conditions: Ce 3+ and Sn 2+ The molar concentration ratio of Ce is 3+ Sn 2+ =1:0.8-1.

5.

4. The electrode according to claim 1, characterized in that, The nitric acid aqueous solution is prepared by mixing fuming nitric acid and water in a volume ratio of fuming nitric acid:water = 1:0.8-1.5; the ethanol aqueous solution is prepared by mixing anhydrous ethanol and water in a volume ratio of anhydrous ethanol:water = 1:0.8-1.

5.

5. The electrode according to claim 1, characterized in that, The diameter of the GCE is 2-5 mm, and the amount of Ce2Sn2O7 suspension added is 3-8 μL.

6. The electrode according to claim 1, characterized in that, The concentration of the phosphate buffered saline is 0.08-0.12 mol / L; the concentration of pyridine in the phosphate buffered saline is 8-12 mmol / L; the concentration of tyrosine in the phosphate buffered saline is 3-3.5 mmol / L; and the methanol-water mixture is prepared by mixing methanol and water in a volume ratio of methanol:water = 1:0.8-1.

5.

7. A sensor for rapid detection of tyrosine, characterized in that, This sensor is based on Ce2Sn2O7-S2O8. 2- / Ru(bpy)3 2+ -TPrA constructs a RECL-MIP sensing system, wherein the cathode of the sensing system is the electrode described in any one of claims 1-6.

8. An application of a sensor for rapid detection of tyrosine, characterized in that, The sensor for rapid detection of tyrosine as described in claim 7 is applied to the determination of tyrosine content in food.

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