Electrochemical Sensor based on Reduced Graphene Oxide/PDAC for Dimethoate Pesticide Detection

Extensive use of pesticides and their accumulation in the environment requires swift actions in terms of their removal, detection, and quantification. Currently, golden standard methods used for quantification of pesticides require expensive instrumentation and are not suitable for quick measurements outside of properly equipped laboratory. Here we investigate the detection of dimethoate (DMT) using PDAC/reduced graphene oxide (rGO)-modified Ag electrodes. The sensor performance depends on the temperature used for the reduction of graphene oxide (GO) in PDAC/GO bi-layer on Ag electrode. Using this combination of nanomaterials, we show the quantification of DMT with either voltammetry or impedance spectroscopies. The former approach relies on direct electrochemical transformations of DMT which are observed at relatively high anodic potential around 0.3 V vs. saturated calomel electrode. Impedance spectroscopy shows complex behavior with increasing DMT concentration, but seems to be rather sensitive to low DMT concentrations. These results present a possible direction to the development of highly efficient electrochemical sensors for pesticide detection.