▎ 摘　　要

NOVELTY - Preparing positive charged composite material comprises adsorption of positive charged surfactant on oxidized graphene and carbon nano-tube using electrostatic adsorption. USE - The material is useful for detecting sodium dodecyl sulfate (SDS) (claimed). ADVANTAGE - The method: has simple operation and moderate operation condition; and is easy to realize and suitable for industrial production. The material has quick, high efficiency and high specificity to polyanionic compounds for electrochemical detection. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for the positive charged composite material prepared by above mentioned method.