▎ 摘　　要

NOVELTY - Preparation method of graphene magnetic nanoelectrodes, involves (a) processing to clean the gold electrode, and (b) preparation of graphene magnetic nanoelectrodes by modifying the graphene/magnetite nanocomposite material to the surface of the gold electrode, drying at room temperature, obtaining the modified electrode by soaking the modified electrode in nano gold sol for 4-6 hours, in 0.01-100 ng.ml-1 alpha-fetoprotein antibody solution for 9-12 hours, and in 0.25 wt.% bovine serum albumin solution for 30-45 minutes to obtain graphene magnetic nanoelectrodes. USE - The method is used for preparation of graphene magnetic nanoelectrodes which are used in an electrochemical immunosensor for the ultra-sensitive detection of immune proteins, where the immune proteins include A-fetal globulin and carcinoembryonic antigen (all claimed). ADVANTAGE - The method constructs a graphene-constructed magnetic nanocomposite on the surface of a gold electrode, and prepares an electrochemical immunosensor based on the graphene magnetic nanoelectrode. The electrochemical immunosensor has high sensitivity, strong antibody adsorption ability, and wide detection concentration range, and is suitable for the detection of immune proteins. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) a graphene magnetic nanoelectrode prepared by the above method; (2) an electrochemical immunosensor based on the graphene magnetic nanoelectrode, comprising a reference electrode, a counter electrode, an electrolyte and the prepared graphene magnetic nanoelectrode, where the graphene magnetic nanoelectrode, the reference electrode and the counter electrode are put together in the electrolyte; and (3) use of the electrochemical immunosensor in the ultra-sensitive detection of immune proteins, where the immune proteins include A-fetal globulin and carcinoembryonic antigen.