▎ 摘　　要

In this study, a novel voltammetric sensor is described for the determination of methyl parathion and parathion based on reduced graphene oxide and hollow gold nanoparticles immobilized on a glassy carbon electrode. Sensitivity is improved by making use of two-step square wave voltammetry. Cyclic voltammetry and square wave voltammetry revealed the sensor to display excellent response to both methyl parathion and parathion, even at very low concentrations. Under optimal conditions, the sensor exhibited a linear response to methyl parathion in the 0.3-10 mu M concentration range, and a linear response to parathion in the 0.11-50 mu M concentration range. The respective detection limits are 0.12 mu M for methyl parathion and 23 nM for parathion. The method was successfully applied to the determination of methyl parathion and parathion in spiked samples and gave recoveries between 76.7% and 112.1%. It was also used to detect residual methyl parathion and parathion in fruit and vegetables, with results correlating well with those obtained by gas chromatography.