▎ 摘　　要

NOVELTY - Three-electrode system electrochemical sensor comprises a base material, conductive track, reference electrode, working electrode and counter electrode are printed on the substrate, there are three groups of the conductive tracks, and one end of the three groups of conductive tracks is respectively connected to the reference electrode, the working electrode and the counter electrode. The reference electrode, working electrode and counter electrode are sequentially decorated with GOD-HRP-CS-MB layer, LOD-HRP-FMN layer and COD-CEH-HRP-β-CD layer from bottom to top. The composition of the GOD-HRP-CS-MB layer comprises horseradish peroxidase, methylene blue, glucose oxidase and chitosan. The components of the LOD-HRP-FMN layer include lactate oxidase and flavin mononucleotide. USE - Three-electrode system electrochemical sensor used in simultaneous quantitative detection of glucose, lactic acid and cholesterol (claimed). ADVANTAGE - None given. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: 1. a method for preparing a three-electrode system electrochemical sensor, which involves: a. taking polyethylene terephthalate as the base material, washing the base material with deionized water and ethanol in sequence, and then drying to obtain a pretreated base material; b. mixing graphene and carbon ink to get GR-C ink; c. mixing the defoamer and GR-C ink to obtain a mixture; d. stirring the mixture, separating the stirred medium from the ink to obtain GR-C conductive paste; e. printing the conductive track on the substrate with silver conductive paste, the working electrode with GR-C conductive paste, the counter electrode with GR-C conductive paste, and the reference electrode with silver chloride conductive paste; f. printing working electrode, counter electrode and reference electrode, printing insulating layer with insulating paste on the conductive track, working electrode, counter electrode and reference electrode of the substrate, drying insulating layer after printing to obtain handle three-electrode system electrochemical sensors; g. dissolving horseradish peroxidase in the bifunctional reagent to obtain HRP-bifunctional reagent solution, dissolving methylene blue in buffer to obtain MB solution, dissolving glucose oxidase and chitosan in a buffer solution to obtain a GOD-CS solution, mixing the MB solution and the GOD-CS solution, first incubate and then sonicating to obtain the GOD-HRP-CS-MB detection solution; h. immersing electrochemical sensor of the three-electrode system to be processed in the buffer solution, scanning electrochemical sensor of the three-electrode system to be processed in the buffer solution by cyclic voltammetry until its reference electrode, working electrode and counter electrode are stable to obtain three-electrode system, taking out system electrochemical sensor from the buffer solution to obtain three-electrode system electrochemical sensor A to be modified; i. dropping the GOD-HRP-CS-MB detection liquid onto the surface of the reference electrode, working electrode and counter electrode of the electrochemical sensor of the three-electrode system to be modified for incubation, dropping the HRP-bifunctional reagent solution onto the three-electrode system to be modified, drying reference electrode, working electrode and counter electrode surface of the electrochemical sensor A are dried, and rinsing reference electrode, the working electrode and the counter electrode surface of the three-electrode system electrochemical sensor A to be modified with deionized water to achieve modification and immobilization to obtain three-electrode system electrochemical sensor modified by GOD-HRP-CS-MB; j. dissolving lactate oxidase and flavin mononucleotide in the buffer and perform ultrasound to obtain LOD-HRP-FMN detection solution; k. immersing GOD-HRP-CS-MB modified three-electrode system electrochemical sensor in the buffer, scanning GOD-HRP-CS-MB modified three-electrode system electrochemical sensor in the buffer by cyclic voltammetry until its reference after the electrode, working electrode and counter electrode are stable, taking out electrochemical sensor of the three-electrode system modified by GOD-HRP-CS-MB from the buffer solution to obtain electrochemical sensor B of the three-electrode system to be modified; l. dropping the LOD-HRP-FMN detection liquid onto the surface of the reference electrode, working electrode and counter electrode of the electrochemical sensor B of the three-electrode system to be modified for incubation, dissolving β-cyclodextrin in sodium hydroxide solution to obtain β-CD-Fc electron mediator solution, adding ferrocene into the β-CD-Fc electronic medium solution for stirring, and then filtering to obtain the filtrate to obtain the β-CD-Fc solution, dissolving cholesterol oxidase, horseradish peroxidase and cholesterol esterase in a buffer to obtain a COD-CEH-HRP solution, mixing COD-CEH-HRP solution and β-CD-Fc solution and performing ultrasonication to obtain COD-CEH-HRP-β-CD detection solution; m. immersing electrochemical sensor modified by the LOD-HRP-FMN three-electrode system in the buffer, scanning electrochemical sensor modified by the LOD-HRP-FMN three-electrode system in the buffer by cyclic voltammetry until its reference electrode and working electrode and after the counter electrode is stabilized, taking out electrochemical sensor of the three-electrode system modified by LOD-HRP-FMN from the buffer solution to obtain electrochemical sensor C of the three-electrode system to be modified; n. dropping the COD-CEH-HRP-β-CD detection liquid onto the surface of the reference electrode, working electrode and counter electrode of the electrochemical sensor C of the three-electrode system to be modified for incubation, and then dropping the HRP-bifunctional reagent solution onto the surface of the electrochemical sensor C to be modified, drying reference electrode, working electrode and counter electrode surface of three-electrode system electrochemical sensor C and rinsing reference electrode, working electrode and counter electrode surface of three-electrode system electrochemical sensor C to be modified with deionized water to achieve modification immobilized to obtain electrochemical sensor modified by COD-CEH-HRP-β-CD three-electrode system, binding hydrophilic material, the blood cell filter membrane and the COD-CEH-HRP-β-CD modified three-electrode system electrochemical sensor and packaging to obtain a product; and 2. a method for simultaneous quantitative detection of glucose, lactic acid and cholesterol in a sample, which involves: using three-electrode system electrochemical sensor to detect the sample to be tested.