▎ 摘　　要

NOVELTY - Preparing layer-by-layer self-assembled sulfonated graphene oxide modified electrode comprises (i) dissolving 0.5 g sulfanilic acid in 5 ml 2% sodium hydroxide solution under magnetic stirring; (ii) adding 0.2 g sodium nitrite, 1 ml hydrochloric acid, and 10 ml ice water to the solution and stirring uniformly; (iii) placing the solution in a ice water bath and stirring at 0 degrees C for 15 minutes; (iv) adding obtained product dropwise to 50 ml graphene oxide solution (10 mg/ml), and stirring vigorously in an ice water bath; (v) centrifuging product to separate a black solid product, vacuum drying and collecting the product; (vi) taking prepared solid sulfonated graphene oxide, dispersing in water, adjusting the pH to 7.4; and (vii) adsorbing self-assembled electrodes and self-assembling in polyethylenimine- fluorocarbon (PEI-Fc) and sulfonated graphene oxide (SGO) solutions by layer-by-layer self-assembly, and exchanging to obtain different layers of PEI-Fc/SGO film modified electrodes. USE - The method is useful for preparing layer-by-layer self-assembled sulfonated graphene oxide modified electrode. ADVANTAGE - The method controls the loading of the modified graphene on the electrode surface and the distribution in the modified layer. DETAILED DESCRIPTION - Preparing layer-by-layer self-assembled sulfonated graphene oxide modified electrode comprises (i) dissolving 0.5 g sulfanilic acid in 5 ml 2% sodium hydroxide solution under magnetic stirring; (ii) adding 0.2 g sodium nitrite, 1 ml hydrochloric acid, and 10 ml ice water to the solution and stirring uniformly; (iii) placing the solution in a ice water bath and stirring at 0 degrees C for 15 minutes; (iv) adding the obtained product dropwise to 50 ml graphene oxide solution (10 mg/ml), and stirring vigorously in an ice water bath at 0 degrees C for 4 hours; (v) centrifuging product to separate a black solid product, vacuum drying and collecting the product; (vi) taking prepared solid sulfonated graphene oxide, dispersing in water, adjusting the pH to 7.4, and controlling the concentration to 5 mg/mL; and (vii) adsorbing self-assembled electrodes and self- assembling in polyethylenimine- fluorocarbon (PEI-Fc) and sulfonated graphene oxide (SGO) solutions by layer-by-layer self-assembly, and exchanging every half hour to obtain different layers of PEI-Fc/SGO film modified electrodes.