▎ 摘　　要

A carbon nitride/graphene composite is synthesized in one step by calcining graphene oxide and melamine. Given that the surface of the carbon nitride is rich in amino groups, the composite material formed by its combination with graphene considerably increases the active sites and enhances the electrical conductivity. Au nanoparticles are ultrasonically added to a carbonitride/graphene composite to form Au NPs/carbon nitride/graphene composites (Au/C3N4/GN) with three-dimensional nanostructures. The introduction of Au nanoparticles makes the Au/C3N(4)/GN composites more sensitive and accurate for the detection of small molecules. To test the electrochemical properties of the composites, chloramphenicol and ciprofloxacin were detected by Au NPs/carbon nitride/graphene-modified electrodes (Au/C3N4/GN/GCE), and satisfactory results were obtained. Under optimized experimental conditions, the detection limits of Au/C3N4/GN/GCE for chloramphenicol and ciprofloxacin were 2.7 x 10(-8) M and 4.2 x 10(-7) M, and the linear ranges of detection were 0.7-120 mu M and 0.6-120 mu M respectively. In addition, the electrochemical sensor was successfully used for quantitative determination of chloramphenicol and ciprofloxacin in milk samples, which clearly revealed its practical feasibility in food analysis. (C) The Author(s) 2018. Published by ECS.