Electrochemical Sensor Based on the Graphene-Nafion Matrix for Sensitive Determination of Organophosphorus Pesticides

Abstract

A graphene-Nafion matrix modified glassy carbon electrode (Graphene-Nafion/GCE) was developed for the determination of organophosphorus pesticides (OPs). Graphene nanosheets were synthesized chemically by the Hummers method. The electrochemical properties of the Graphene-Nafion/GCE were investigated by cyclic voltammetry and square-wave voltammetry. It was found that the graphene-Nafion matrix not only enhanced the adsorption to OPs, but also improved the sensitivity of the OPs determination due to the synergistic effect of graphene nanosheets and Nafion. Methyl parathion was selected as a model of OPs. Compared to the unmodified electrode, the peak current obviously increased and the reduction peak potential positively shifted. Under the optimum conditions, the response current of stripping voltammetry was linearly related to the concentration of methyl parathion over the range from 0.02 to 20 µg/ml with a detection limit of 1.6 ng/ml. The sensor was successfully applied in the determination of methyl parathion in vegetable samples by the standard addition method.