▎ 摘　　要

In this work, a polypyrrole (PPy)-graphene oxide (GO) composite film was electrodeposited on the composite ceramic carbon electrode (CCE) from a solution containing only pyrrole and GO. After further electrochemical reduction and oxidation, a three-dimensional over-oxidized polypyrrole-reduced graphene oxide composite film-modified electrode (3D-OPPy/ERGO/CCE) was obtained. The surface morphology and the electrochemical properties of the modified electrode were studied carefully. This modified electrode was used for the simultaneous determination of dihydroxybenzene isomers with excellent analytical performance due to the good selectivity of OPPy, high electrochemical activity of ERGO, and good permeability of the three-dimensional porous structure of the composite film. Under the optimum conditions, the linear ranges for the simultaneous determination of hydroquinone (HQ), catechol (CC) and resorcinol (RS) by differential pulse voltammetry (DPV) in phosphate buffer (pH 6.0) were 0.50-100 mu M (HQ), 0.50-200 mu M (CC) and 2.00-200 mu M (RS), with the detection limits (at an SNR of 3) of 0.1 mu M (HQ and CC) and 0.7 mu M (RS), respectively. This modified electrode was used for the determination of dihydroxybenzene isomers in local river water with satisfactory results.