▎ 摘　　要

In this work, poly(cetyltrimethylammoniumbromide)/graphene oxide (poly(CTAB)/GO) composite was synthesized via in situ electropolymerisation and used as novel sensor for morphine (MO) detection. The CTAB functionalized graphene sheet offers large surface area which remarkably enhances the electrochemical response of MO compared to that of bare glassy carbon electrode (GCE). The surfactant CTAB with its hydrophilic head and hydrophobic tail plays a significant role in enhancing the catalytic property of the electrode. The electrostatic interaction between cationic group of poly (CTAB) and lone pair on nitrogen atom of tertiary amine group of MO favours the electro oxidation of tertiary amine group rather than phenolic group. A detection limit of 0.36 mu M and a wide linear range of 50-60 mu M feature the merits of the proposed composite in the analysis of MO. This sensor shows good repeatability, reproducibility, stability and anti interference properties. It is also tested in real samples. Graphic abstract Schematic representation of the electrochemical behaviour of the modified electrode poly (CTAB)/GO/GCE towards morphine.