▎ 摘　　要

NOVELTY - Preparing an electrochemical immunosensor, by (a) preparing a carboxylated graphene-gold composite nanomaterial, taking polyvinylpyrrolidone and ascorbic acid dissolved in double distilled water, adding the carboxylated graphene, heating the mixture at 80-120 degrees C for 10-30 minutes, dropwise adding chloroauric acid, continuously stirring, reacting for 3-5 hours, and obtaining carboxylated graphene-gold composite nanomaterial by centrifugation with ethanol, (b) polishing glassy carbon electrode with aluminum oxide powder, ultrasonically processing with nitric acid, absolute ethanol and distilled water, adding prepared COOH-GO-Au composite nanomaterials on glassy carbon electrode, rinsing with distilled water, and obtaining a COOHGO-Au/GCE sensor, and (c) incubating COOH-GOAu/GCE in aflatoxin B1 (AFB1) antibody, rinsing with phosphate buffer, drying, placing in bovine serum albumin solution, incubating, drying, incubating in AFB1 solution, and drying obtained product. USE - The method is useful for preparing the electrochemical immunosensor for detecting AFB1 (all claimed). ADVANTAGE - The prepared electrochemical immunosensor rapidly detects AFB1. DETAILED DESCRIPTION - Method for preparing an electrochemical immunosensor, involves (a) preparing a carboxylated graphene-gold composite nanomaterial, taking polyvinylpyrrolidone and ascorbic acid dissolved in double distilled water, adding the carboxylated graphene, heating the mixture at 80-120 degrees C for 10-30 minutes, dropwise adding chloroauric acid, continuously stirring, reacting for 3-5 hours, and obtaining carboxylated graphene-gold composite nanomaterial by centrifugation with ethanol, (b) preparing modified electrode by polishing glassy carbon electrode with aluminum oxide powder, ultrasonically processing with nitric acid, absolute ethanol and distilled water for 1-3 minutes, drying, dropwise adding prepared COOH-GO-Au composite nanomaterials on glassy carbon electrode, drying, rinsing with distilled water, drying and obtaining a COOHGO-Au/GCE sensor, and (c) at 37 degrees C, incubating COOH-GOAu/GCE in aflatoxin B1 (AFB1) antibody, rinsing with phosphate buffer, drying, placing in bovine serum albumin solution, incubating at 37 degrees C, rinsing with phosphate buffer, drying, incubating in AFB1 solution at 37 degrees C for 30 minutes, rinsing with phosphate buffer, and drying obtained product.