▎ 摘　　要

NOVELTY - The utility model claims an electrochemical sensor based on silver sulphide graphene composite material modified electrode, comprising: a working electrode; a reference electrode; a counter electrode; the working electrode comprises: a base electrode; a silver sulphide graphene composite material arranged on the outer surface of the substrate electrode; and a Nafion layer arranged on the surface of the silver sulphide graphene composite material. The base electrode is glassy carbon electrode. The prepared silver sulphide graphene composite material meets the advantages of good conductivity, large specific surface area and so on. The excellent electrochemical active electrode material is applied to the rapid detection of the concentration of the drug gatifloxacin. The electrochemical detection method has low cost, fast response, simple device, high sensitivity, good reliability and so on; it is convenient to realize the fast detection of trace amount medicine; it has good economic and social benefits.