Reduction detection electrode with constant oxygen background and preparation method thereof

Abstract

The invention discloses a reduction detection electrode with a constant oxygen background and a preparation method thereof, relates to the technical field of detection electrode preparation, and aims to solve the problem that oxygen interferes electrochemical detection in the prior art. Performing H2O2 electrocatalyst modification on the oxygen supply material substrate electrode to obtain an oxygen supply material substrate electrode modified with a H2O2 electrocatalyst; oxidase is fixed to the surface of an oxygen supply material substrate electrode modified with a H2O2 electrocatalyst, and the reduction detection electrode with the constant oxygen background is obtained. According to the present invention, the oxygen interference can be effectively avoided, the stable and accurate detection signal can be provided, and the characteristics of high sensitivity, high selectivity, simple operation and high cost efficiency can be provided so as to meet the requirements of clinical diagnosis, environmental monitoring, food safety and other fields on the high-precision electrochemical detection.

Description

Technical Field

[0001] The present invention relates to a reduction detection electrode with a constant oxygen background and a preparation method thereof, belonging to the technical field of detection electrode preparation. Background Art

[0002] In the field of preparation and application of electrochemical biosensors, traditional detection methods mainly rely on the oxidation current method. This method determines the concentration of the substance to be detected by measuring the current signal generated during the oxidation process. However, this method has some significant limitations. Especially during the detection process, the electro-oxidation reactions of easily reducible substances (such as ascorbic acid, uric acid, etc.) will generate interference signals, seriously affecting the accuracy and reliability of the detection results. In addition, the oxidation current method does not perform well in terms of high sensitivity and selectivity detection, limiting its application in the analysis of complex biological samples.

[0003] To overcome the limitations of the oxidation current method, researchers have tried to use reduction methods for electrochemical detection. This method reduces substances such as hydrogen peroxide at a negative reduction potential to avoid interference from easily oxidizable substances. However, the reduction method faces the problem of oxygen interference. Since oxygen is ubiquitous in nature and has a strong ability to gain electrons, it will be reduced at the reduction potential, generating a strong current signal, thus interfering with the signal of the substance to be detected. This results in unstable and inaccurate detection signals, making it difficult to achieve accurate quantitative analysis.

[0004] To reduce the interference of oxygen on the reduction method, researchers have adopted strategies of pre-removing oxygen and using specific electrocatalysts. This includes deoxygenating the sample before detection to reduce the concentration of oxygen. Although this method can reduce the interference of oxygen to a certain extent, its process is cumbersome, requiring additional equipment and steps, increasing the complexity and cost of detection. More importantly, pre-removing oxygen cannot completely remove oxygen, and there is still a risk of residual oxygen interfering with the detection results. Specific electrocatalysis enables it to avoid the electro-reduction of oxygen within a certain potential range, but the complexity and stability of the catalyst limit the use of this method. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies in the prior art, and provide a reduction detection electrode with a constant oxygen background and a preparation method thereof, which can effectively avoid the interference of oxygen, provide stable and accurate detection signals, and have the characteristics of high sensitivity, high selectivity, simple operation and high cost-effectiveness, so as to meet the needs of high-precision electrochemical detection in the fields of clinical diagnosis, environmental monitoring, food safety, etc.

[0006] To achieve the above purpose, the present invention is implemented by the following technical solutions: On the one hand, the present invention provides a method for preparing a reduction detection electrode with a constant oxygen background, comprising: Preparing an oxygen-supplying material substrate electrode; Modifying the oxygen-supplying material substrate electrode with an H2O2 electrocatalyst to obtain an oxygen-supplying material substrate electrode modified with an H2O2 electrocatalyst; Fixing an oxidase on the surface of the oxygen-supplying material substrate electrode modified with an H2O2 electrocatalyst to obtain a reduction detection electrode with a constant oxygen background.

[0007] Further, the oxygen-supplying material substrate electrode is an oxygen-constant porous fiber paper or an oxygen-constant porous hollow particle @ carbon substrate electrode.

[0008] Further, the method for preparing the oxygen-constant porous fiber paper comprises: Pre-treating a porous conductive carbon fiber membrane to obtain a porous conductive carbon fiber substrate; Diluting a polytetrafluoroethylene emulsion to a polytetrafluoroethylene suspension; Immersing the porous conductive carbon fiber substrate in the polytetrafluoroethylene suspension, standing, and then drying to obtain a dried porous conductive carbon fiber substrate; Heating the dried porous conductive carbon fiber substrate and naturally cooling it to obtain the oxygen-constant porous fiber paper.

[0009] Further, the standing time is 1 to 3 h; and / or, the drying temperature is 60 to 100 °C; and / or, the heating parameters include heating at 150 to 600 °C for 5 to 120 min.

[0010] Further, the method for preparing the oxygen-constant porous hollow particle @ carbon substrate electrode comprises: Pre-treating a porous hollow particle and a carbon substrate electrode respectively to obtain a pre-treated porous hollow silicon sphere and a carbon substrate electrode; Placing the pre-treated porous hollow particle in a benzene solution of a silane coupling agent, soaking, drying, heating at a and then naturally cooling to obtain an oxygen-rich porous hollow silicon sphere; Mixing a Nafion ethanol solution and the oxygen-rich porous hollow silicon sphere uniformly to obtain a suspension particle solution; Dropping the particle solution onto the surface of the pre-treated carbon substrate electrode, naturally drying and then heating at b to obtain a carbon substrate electrode.

[0011] Further, the pre-treatment includes: immersing in a mixed solvent, ultrasonic cleaning for multiple times and then drying; Wherein, the cleaning time is 1 to 30 min, and the drying temperature range is 60 to 150 °C; The mixed solvent is composed of ethanol, acetone and water, and the mass ratio of ethanol, acetone and water in the mixed solvent is 1 to 10:1 to 10:1 to 10.

[0012] Furthermore, at least one of the following conditions is satisfied: The size of the porous hollow particles is 1 - 800 μm; The benzene solution of the silane coupling agent is one of the benzene solutions of KH550, KH560, KH570, KH792, DL602, and DL171; The concentration of the benzene solution of the alkyl coupling agent is 5 - 100 wt%; The soaking time is 10 - 180 min; The drying temperature is 60 - 100 °C; The condition parameters of heating a include adding for 20 - 180 min at 100 - 600 °C; The concentration of Nafion in the ethanol solution of Nafion is 0.1 - 75 wt%; The concentration of the suspension particle solution is 1 - 500 mg / mL; The condition parameters of heating b include heating for 10 - 180 min at 50 - 150 °C.

[0013] Furthermore, the method of modifying the oxygen supply material substrate electrode with the H2O2 electrocatalyst to obtain the oxygen supply material substrate electrode modified with the H2O2 electrocatalyst adopts the electrochemical deposition method or the physical phase deposition method; The specific process of the electrochemical deposition method includes: Placing the oxygen supply material substrate electrode on the side wall of the electrochemical cell, using a mixed solution of 1 - 15 mM chloroplatinic acid and 0.1 - 0.8 mM sulfuric acid as the electrodeposition solution, setting up a three - electrode system, where the three - electrode system includes using the oxygen supply material substrate electrode as the working electrode, the H2O2 electrocatalyst as the counter electrode, and Ag / AgCl as the reference electrode; Depositing at a potential of - 0.05 - - 1.50 V for 5 - 600 s, and after washing the oxygen supply material substrate electrode with water, obtaining the oxygen supply material substrate electrode modified with the H2O2 electrocatalyst; The specific process of the physical phase deposition method includes: Depositing the H2O2 electrocatalyst on the surface of the oxygen supply material substrate electrode by electron beam evaporation to obtain the oxygen supply material substrate electrode modified with platinum nanoparticles; Among them, the deposition thickness range of the H2O2 electrocatalyst is 5 - 100 nm, and the H2O2 electrocatalyst is one of platinum, manganese dioxide, iron - based materials, nitrogen - doped carbon, and cobalt - based oxides.

[0014] Furthermore, the method of immobilizing the oxidase on the surface of the oxygen supply material substrate electrode modified with the H2O2 electrocatalyst to obtain the reduction detection electrode with a constant oxygen background adopts the embedding fixation method or the combination of covalent cross - linking and embedding method; The specific embedding and fixing method includes: Place the oxygen supply material base electrode modified with the H2O2 electrocatalyst on the mold, and expose an area accounting for 10 - 90% of the area of the oxygen supply material base electrode. Drop the oxidase solution, and then drop the chitosan acetate solution when the solution dries, and let it dry. The oxidase solution uses a lactate oxidase solution with a concentration of 1 - 50 mg / mL, and the concentration of the chitosan acetate solution is 0.1 - 50 mg / mL. The specific covalent cross - linking and embedding combination method includes: Place the oxygen supply material base electrode modified with the H2O2 electrocatalyst on the mold of the electrochemical reaction device, and expose a partial area. Drop the mixed solution and let it dry. The preparation method of the mixed solution includes: Mix 0.1 - 50 mg / mL of chitosan acetate solution, 1 - 50 mg / mL of lactate oxidase solution, 1 - 20 wt% of glutaraldehyde aqueous solution and water to form a uniform mixed solution, and let it stand at room temperature for 1 - 5 h to obtain the mixed solution.

[0015] On the other hand, the present invention also provides a reduction detection electrode with a constant oxygen background, which is prepared by the preparation method of the reduction detection electrode with a constant oxygen background described in any one of the above.

[0016] Compared with the prior art, the beneficial effects achieved by the present invention: The reduction detection electrode prepared by the present invention can be used as the negative electrode (working electrode) of a lactate detection electrochemical sensor. A large amount of air / oxygen is captured in the pores / gaps of the oxygen supply material, and it is transformed into an oxygen supply material containing a large amount of oxygen. Using the oxygen supply material containing a large amount of oxygen directly as the base electrode can effectively provide a stable oxygen level in the electrode detection area of the sensor, transform the oxygen interference into stable background information, thereby reducing the interference problem of oxygen during the use of the sensor, and improving the stability and accuracy of the lactate detection electrochemical sensor. The reduction detection electrode prepared by the present invention has the characteristics of high sensitivity, high selectivity, simple operation and high cost - effectiveness, so as to meet the requirements of high - precision electrochemical detection in the fields of clinical diagnosis, environmental monitoring, food safety, etc. Description of the Drawings

[0017] Figure 1Schematic diagram for detecting lactic acid at different concentrations by the lactic acid detection sensor assembled with the oxygen-constant electrode based on Pt-modified oxygen-constant carbon fiber paper prepared in Example 1 of the present invention. Among them, a is the chronoamperometric response of the lactic acid sensor based on the oxygen-constant electrode at different lactic acid concentrations (0 - 40 mM) in 0.1 M PBS (pH 7.4), and b is the schematic diagram of the concentration-current curve obtained from the current signals at 10 s corresponding to different lactic acid concentrations when detecting lactic acid at different concentrations (error bar n = 3); Figure 2 Schematic scanning electron microscope image of the oxygen-constant electrode based on Pt-modified oxygen-constant carbon fiber paper prepared in Example 2 of the present invention; Figure 3 Schematic diagram of the concentration-current curve obtained from the current signals at 10 s corresponding to different lactic acid concentrations when detecting lactic acid at different concentrations by the lactic acid detection sensor assembled with the oxygen-constant electrode based on Pt-modified oxygen-constant carbon fiber paper prepared in Example 2 of the present invention (error bar n = 3); Figure 4 Schematic diagram of the concentration-current curve obtained from the current signals at 10 s corresponding to different lactic acid concentrations when detecting lactic acid at different concentrations by the lactic acid detection sensor assembled with the oxygen-constant electrode based on Pt-modified carbon substrate electrode prepared in the comparative example of the present invention (error bar n = 3). Detailed implementation manners

[0018] The present invention will be further described below with reference to the accompanying drawings. The following examples are only used to more clearly illustrate the technical solutions of the present invention and cannot be used to limit the protection scope of the present invention. Example 1

[0019] The present invention provides a preparation method for a reduction detection electrode with a constant oxygen background, using an oxygen-constant porous fiber paper as the oxygen-supplying material substrate electrode, which includes the following steps: Pretreat the porous conductive carbon fiber substrate: Immerse a porous conductive carbon fiber membrane with a size of 1 cm × 1 cm into a solvent mixture of ethanol, acetone, and water in a ratio of 1:1:1, and use ultrasonic cleaning technology to clean for 10 minutes to remove surface impurities. The cleaned carbon fiber membrane is dried at a temperature of 80 °C for subsequent processing.

[0020] Prepare the oxygen-constant porous fiber paper: Dilute the polytetrafluoroethylene emulsion to a concentration of 10 wt% to form a suspension. Immerse the pretreated carbon fiber membrane into the above suspension, keep it for 1 hour, and then dry it at a temperature of 80 °C. Heat the dried carbon fiber membrane at a temperature of 350 °C for 5 to 120 minutes, and then cool it naturally to obtain a porous fiber paper with oxygen-constant ability.

[0021] Clean the oxygen-constant carbon fiber paper: Immerse the oxygen-constant carbon fiber paper in the mixed solvent again and perform ultrasonic cleaning three times to ensure thorough cleaning.

[0022] Modify the nano-platinum particles: Modify the oxygen-constant carbon fiber paper with nano-platinum particles, and electrochemical deposition or physical vapor deposition techniques can be used. If electrochemical deposition is adopted, fix the carbon fiber paper on the side wall of the electrochemical cell, use a mixed solution of 10 mM chloroplatinic acid and 0.5 M sulfuric acid as the electroplating solution, set up a three-electrode system (the working electrode is the carbon fiber paper, the counter electrode is a platinum wire, and the reference electrode is Ag / AgCl), perform electroplating at -0.3 V for 500 seconds, and then wash the electrode surface with water.

[0023] Fix the lactate oxidase: Fix the carbon fiber paper on the mold, drop 20 mg / (mL·cm 2 ) aqueous solution of lactate oxidase. When the solution is about to dry, drop 10 mg / mL chitosan acetate solution with the concentration of acetic acid being 1 wt%, and finally place it in a dryer to dry, obtaining an oxygen-constant electrode based on Pt-modified oxygen-constant carbon fiber paper. Example 2

[0024] This example provides a preparation method of a reduction detection electrode with a constant oxygen background, using an oxygen-constant porous hollow silica sphere@carbon substrate electrode as the oxygen-supplying material substrate electrode, which includes the following steps: Pretreat the porous hollow silica spheres: Immerse the porous hollow silica spheres with a size of 1 μm in a solvent mixed by ethanol, acetone and water in a certain ratio (1:1:1), and use ultrasonic cleaning technology to clean for 10 minutes to remove surface impurities. The cleaned porous hollow silica spheres are dried at a temperature of 60 °C for subsequent treatment.

[0025] Prepare oxygen-rich porous hollow silica spheres: Place the porous hollow silica spheres with a size of 500 μm in a 30% wt benzene solution of silane coupling agent (KH550), soak for 30 minutes, and then dry at a temperature of 80 °C. Heat the dried porous hollow silica spheres at a temperature of 150 °C for 60 minutes and cool naturally to obtain porous hollow silica spheres with oxygen-supplying ability.

[0026] Prepare the sensor carbon substrate electrode: Immerse the carbon substrate electrode in a solvent mixed by ethanol, acetone and water in a ratio of 1:1:1, and perform ultrasonic cleaning three times to ensure thorough cleaning.

[0027] Prepare the oxygen-constant porous hollow silica sphere@carbon substrate electrode: Prepare a 100 mg / mL ethanol solution of oxygen-rich porous hollow silica spheres using ethanol added with 5% Nafion. Subsequently, take 50 μL of the silica sphere solution and drop it onto a 1×1 cm 2On the carbon-based electrode with an area, air-dry naturally. Finally, heat it at 100 °C for 30 min to finally obtain an oxygen-constant porous hollow silica sphere @ carbon-based electrode.

[0028] Modifying nano-platinum particles: Modify the oxygen-constant porous hollow silica sphere @ carbon-based electrode with nano-platinum particles. Specific process: Using the magnetron sputtering method, in an argon atmosphere (atmospheric pressure 0.8 Pa), sputter a pure platinum target (purity 99.99%) for 120 s with a current of 30 mA.

[0029] Fixing lactate oxidase: Fix lactate oxidase on the surface of the oxygen-constant porous hollow silica sphere @ carbon-based electrode modified with nano-platinum particles by the embedding fixation method. Specifically: When using the embedding fixation method, fix the oxygen-constant porous hollow silica sphere @ carbon-based electrode modified with platinum particles on a mold, expose the required size area (1 cm 2 )), dropwise add an aqueous solution of lactate oxidase at 10 mg / (mL·cm 2 ), when the solution is about to dry, then dropwise add a chitosan acetate solution at 10 mg / mL, where the concentration of acetic acid is 1 wt%, and finally, place it in a dryer and dry for 24 hours to obtain an oxygen-constant electrode based on Pt-modified oxygen-rich porous hollow silica spheres.

[0030] Comparative example: This comparative example provides a preparation method of a reduction detection electrode, including the following steps: Preparation of carbon-based electrode: Immerse the commercial carbon-based electrode in a solvent mixed with ethanol, acetone and water in a ratio of 1:1:1, and perform ultrasonic cleaning three times to ensure thorough cleaning.

[0031] Modifying nano-platinum particles: Modify the carbon-based electrode with nano-platinum particles. Specific process: Using the magnetron sputtering method, in an argon atmosphere (atmospheric pressure 0.8 Pa), sputter a pure platinum target (purity 99.99%) for 120 s with a current of 30 mA.

[0032] Fixing lactate oxidase: Fix lactate oxidase on the surface of the carbon-based electrode modified with nano-platinum particles by the embedding fixation method. Specifically: Fix the carbon-based electrode modified with platinum particles on a mold, expose the required size area (0.2 - 5 cm 2 ), dropwise add an aqueous solution of lactate oxidase at 1 to 50 mg / (mL·cm 2 ), when the solution is about to dry, then dropwise add a chitosan acetate solution at 10 mg / mL, where the concentration of acetic acid is 10 wt%, and finally, place it in a dryer and dry for 24 hours to obtain an oxygen-constant electrode based on Pt-modified carbon-based electrode.

[0033] The reduction detection electrodes obtained in Example 1, Example 2 and the comparative example were tested as follows: First, the reduction detection electrode with a constant oxygen background obtained in Example 1 was used as the working electrode, a Pt wire as the counter electrode, and Ag / AgCl as the reference electrode to assemble a lactic acid detection sensor. The sensor was placed in a PBS solution with pH = 7.4. Subsequently, lactic acid with different concentrations was added to the solution, and an I-t test was performed (applied potential: -0.3 V vs. Ag / AgCl / saturated KCl), as Figure 1 shown in Figure 1 a, and the current signals at 10 s corresponding to different concentrations of lactic acid were recorded to obtain a concentration-current curve, as

[0034] shown in Figure 1 b.

[0035] Combined with Figure 2 it can be seen that the constant oxygen electrode system effectively maintains the dynamic balance between the oxygen reduction current and the H2O2 generation current through a continuous and stable oxygen supply mechanism, making the detection current show a good linear positive correlation with the lactic acid concentration (0 - 30 mM), and demonstrating excellent detection stability and wide-range response characteristics.

[0036] Then, a scanning electron microscope was used to observe the oxygen constant electrode based on Pt-modified oxygen-rich porous hollow silica spheres obtained in Example 2. The inserted figure shows that the contact angle CA = 55 ± 2°, as Figure 3 shown. The ordered stacking structure of the oxygen constant electrode based on Pt-modified oxygen-rich porous hollow silica spheres effectively stores oxygen in its internal cavity, and the contact angle of the lactic acid oxidase layer uniformly loaded on the surface is (55 ± 2°). This design not only maintains oxygen reserve but also realizes the efficient transmission of lactic acid.

[0037] The reduction detection electrode with a constant oxygen background obtained in the comparative example was used as the working electrode, a Pt wire as the counter electrode, and Ag / AgCl as the reference electrode to assemble a lactic acid detection sensor. The sensor was placed in a PBS solution with pH = 7.4. Subsequently, lactic acid with different concentrations was added to the solution, and an I-t test was performed (potential: -0.3 V), and the current signals at 10 s corresponding to different concentrations of lactic acid were recorded to obtain a concentration-current curve, as Figure 4As shown, in the electrode system without a constructed constant oxygen mechanism, when the lactic acid concentration gradient increases, the current signal does not increase with the increase in concentration, but an abnormal current decay phenomenon occurs.

[0038] This is due to the dual effects of insufficient oxygen supply in the electrode system: on the one hand, the enzymatic reaction continuously consumes dissolved oxygen, resulting in the decay of the oxygen reduction current; on the other hand, although the enzymatic reaction by-product H2O2 can generate a reduction current, its increment cannot compensate for the loss of the oxygen reduction current, ultimately leading to a decrease in the overall response signal with the increase in lactic acid concentration. This indicates that it cannot be applied to actual detection and also confirms the crucial role of the construction of a steady-state oxygen electrode in maintaining the functional integrity of the enzyme electrode.

[0039] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A preparation method of a reduction detection electrode with a constant oxygen background, characterized in that Comprising: Preparing a base electrode of an oxygen supply material; Modifying the base electrode of the oxygen supply material with an H2O2 electrocatalyst to obtain a base electrode of the oxygen supply material modified with the H2O2 electrocatalyst; Fixing an oxidase on the surface of the base electrode of the oxygen supply material modified with the H2O2 electrocatalyst to obtain a reduction detection electrode with a constant oxygen background.

2. The preparation method of the reduction detection electrode with a constant oxygen background according to claim 1, characterized in that, The base electrode of the oxygen supply material is an oxygen-constant porous fiber paper or an oxygen-constant porous hollow particle @ carbon base electrode.

3. The preparation method of the reduction detection electrode with a constant oxygen background according to claim 2, characterized in that, The preparation method of the oxygen-constant porous fiber paper includes: Pre-treating a porous conductive carbon fiber membrane to obtain a porous conductive carbon fiber base; Diluting a polytetrafluoroethylene emulsion to a polytetrafluoroethylene suspension; Immersing the porous conductive carbon fiber base in the polytetrafluoroethylene suspension, standing, and then drying to obtain a dried porous conductive carbon fiber base; Heating the dried porous conductive carbon fiber base and naturally cooling to obtain the oxygen-constant porous fiber paper.

4. The preparation method of the reduction detection electrode with a constant oxygen background according to claim 3, characterized in that The standing time is 1 to 3 h; and / or, the drying temperature is 60 to 100 °C; and / or, the heating parameters include heating at 150 to 600 °C for 5 to 120 min.

5. The preparation method of the reduction detection electrode with a constant oxygen background according to claim 2, characterized in that The preparation method of the oxygen-constant porous hollow particle @ carbon base electrode includes: Pre-treating a porous hollow particle and a carbon base electrode respectively to obtain a pre-treated porous hollow silica sphere and a carbon base electrode; Placing the pre-treated porous hollow particle in a benzene solution of a silane coupling agent, soaking, drying, heating a and then naturally cooling to obtain an oxygen-rich porous hollow particle; Mixing a Nafion ethanol solution and the oxygen-rich porous hollow particle evenly to obtain a suspension particle solution; Dropping the suspension particle solution on the surface of the pre-treated carbon base electrode, naturally drying and then heating b to obtain a carbon base electrode.

6. The preparation method of the reduction detection electrode with a constant oxygen background according to claim 3 or 5, characterized in that, The pre-treatment includes: immersing in a mixed solvent, ultrasonic cleaning for several times and then drying; Wherein, the cleaning time is 1 to 30 min, and the drying temperature range is 60 to 150 °C; The mixed solvent is composed of ethanol, acetone and water, and the mass ratio of ethanol, acetone and water in the mixed solvent is 1 to 10:1 to 10:1 to 10.

7. The preparation method of the reduction detection electrode with a constant oxygen background according to claim 5, characterized in that At least one of the following conditions is satisfied: The size of the porous hollow particle is 1 to 800 μm; The benzene solution of the silane coupling agent is one of the benzene solutions of KH550, KH560, KH570, KH792, DL602 and DL171; The concentration of the benzene solution of the alkane coupling agent is 5 to 100 wt%; The soaking time is 10 to 180 min; The drying temperature is 60 to 100 °C; The condition parameters of the heating a include heating at 100 to 600 °C for 20 to 180 min; The concentration of Nafion in the Nafion ethanol solution is 0.1 to 75 wt%; The concentration of the suspension particle solution is 1 to 500 mg / mL. The condition parameters for heating b include heating at 50~150°C for 10~180 min.

8. The preparation method of the reduction detection electrode with a constant oxygen background according to claim 1, characterized in that, The method for modifying the oxygen supply material substrate electrode with the H2O2 electrocatalyst to obtain the oxygen supply material substrate electrode modified with the H2O2 electrocatalyst adopts the electrochemical deposition method or the physical phase deposition method; The specific electrochemical deposition method includes: Placing the oxygen supply material substrate electrode on the side wall of the electrochemical cell, using a mixed solution of 1~15 mM chloroplatinic acid and 0.1~0.8 mM sulfuric acid as the electrodeposition solution, setting up a three-electrode system, and the three-electrode system includes using the oxygen supply material substrate electrode as the working electrode, the H2O2 electrocatalyst as the counter electrode, and Ag / AgCl as the reference electrode; Depositing at a potential of -0.05~-1.50 V for 5~600 s, and after washing the oxygen supply material substrate electrode with water, the oxygen supply material substrate electrode modified with the H2O2 electrocatalyst is obtained; The specific physical phase deposition method includes: Depositing the H2O2 electrocatalyst on the surface of the oxygen supply material substrate electrode by electron beam evaporation to obtain the oxygen supply material substrate electrode modified with platinum nanoparticles; Among them, the deposition thickness range of the H2O2 electrocatalyst is 5~100 nm, and the H2O2 electrocatalyst is one of platinum, manganese dioxide, iron-based materials, nitrogen-doped carbon, and cobalt-based oxides.

9. The preparation method of the reduction detection electrode with a constant oxygen background according to claim 1, characterized in that, The method for fixing the oxidase on the surface of the oxygen supply material substrate electrode modified with the H2O2 electrocatalyst to obtain the reduction detection electrode with a constant oxygen background adopts the embedding fixation method or the combination of covalent cross-linking and embedding; The specific embedding fixation method includes: Placing the oxygen supply material substrate electrode modified with the H2O2 electrocatalyst on the mold, and exposing an area accounting for 10~90% of the area of the oxygen supply material substrate electrode, dropping the oxidase solution, and then dropping the chitosan acetate solution when the solution dries, and drying; The oxidase solution adopts a lactate oxidase solution, and its concentration is 1~50 mg / mL, and the concentration of the chitosan acetate solution is 0.1~50 mg / mL; The specific combination of covalent cross-linking and embedding includes: Placing the oxygen supply material substrate electrode modified with the H2O2 electrocatalyst on the mold of the electrochemical reaction device, and exposing a part of the area, dropping the mixed solution, and drying; The preparation method of the mixed solution includes: Mixing 0.1~50 mg / mL of chitosan acetate solution, 1~50 mg / mL of lactate oxidase solution, 1~20 wt% of glutaraldehyde aqueous solution and water to form a uniform mixed solution, and standing at room temperature for 1~5 h to obtain the mixed solution.

10. A reduction detection electrode with a constant oxygen background, characterized in that It is prepared by the preparation method of the reduction detection electrode with a constant oxygen background according to any one of claims 1~9.

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