▎ 摘　　要

NOVELTY - Performing electrochemical immunodetection of total homocysteine involves preparing SAH electrochemical immunosensor by mixing the nanocomposite material with water to obtain suspension A, mixing the binder with water to obtain solution B, and mixing streptavidin with water to obtain solution C. Suspension A, solution B and solution C are mixed and dripped on the electrode surface to obtain a modified electrode. The nanocomposite material is selected from Au-NPs/RGO/SiO2 nanocomposite material, Au-NPs/SiO2 nanocomposite material or Au-NPs/RGO nanocomposite material. The binder is selected from chitosan. The biotinylated SAH antibody is drop-coated on the surface of the modified electrode, and after the reaction is incubated, rinsed with a phosphate buffer solution. USE - Method for performing electrochemical immunodetection of total homocysteine. ADVANTAGE - The method enables to perform electrochemical immunodetection of total homocysteine, which has short detection time and higher sensitivity, accuracy and specificity, and realizes a fast, accurate, highly sensitive, simple and inexpensive detection of tHcy, and without the need for large-scale testing equipment, it is expected to achieve small and intelligent and fast and easy detection at the bedside. DETAILED DESCRIPTION - Performing electrochemical immunodetection of total homocysteine involves preparing SAH electrochemical immunosensor by mixing the nanocomposite material with water to obtain suspension A, mixing the binder with water to obtain solution B, and mixing streptavidin with water to obtain solution C. Suspension A, solution B and solution C are mixed and dripped on the electrode surface to obtain a modified electrode. The nanocomposite material is selected from Au-NPs/RGO/SiO2 nanocomposite material, Au-NPs/SiO2 nanocomposite material or Au-NPs/RGO nanocomposite material. The binder is selected from chitosan. The biotinylated SAH antibody is drop-coated on the surface of the modified electrode, and after the reaction is incubated, rinsed with a phosphate buffer solution. The bovine serum albumin solution is then applied dropwise to the modified electrode after the treatment, and after blocking at room temperature, it is rinsed with a phosphate buffer solution to obtain an SAH electrochemical immunosensor. The SAH electrochemical immunosensors are incubated in SAH antigen solutions at different concentrations, rinsed with phosphate buffered solution to obtain an electrochemical immunosensor incubated with SAH antigen. The electrochemical immunosensor for incubating the SAH antigen is used as the working electrode, the saturated calomel electrode or the Ag/AgCl electrode is used as the auxiliary electrode, and the platinum sheet electrode is used as the counter electrode. The electrochemical signal is detected by differential pulse voltammetry, and the working curves of SAH and current signal responses at different concentrations are obtained ion the potassium ferricyanide test solution. The sample to be tested is reacted with the sample treatment solution containing the disulfide bond reducing agent. The SAH hydrolase solution and excess adenosine are used to convert Hcy in the sample to be tested into SAH to obtain a processed sample solution. The SAH electrochemical immunosensor is incubated in the treated sample solution, then rinsed with a phosphate buffer, used as a working electrode, and the current response is detected in the potassium ferricyanide test solution. According to the working curve the content of SAH in the sample to be tested is obtained, and the content of total homocysteine in the sample to be tested is further obtained by calculation.