Development and validation of a new sensor for methomyl detection

Abstract

A new highly sensitive and selective voltammetric method for the determination of methomyl insecticide is reported. After alkaline hydrolysis of methomyl to its oxime, the ability of this insecticide to inhibit the electrocatalytic oxidation of its hydrolysis product at a copper oxide modified carbon paste electrode (Cu-CPE) was studied. The base signal was obtained by the electrocatalytic oxidation of a fix concentration of methomyl oxime (MO) at the studied modified electrode. All electrochemical measurements for optimization and evaluation of the developed sensor were performed using square wave voltammetry and cyclic voltammetry techniques. Under the optimized conditions, an excellent sensitivity and selectivity to methomyl in terms of inhibition percentage was obtained at Cu-CPE (50% CuO) with a low detection limit of about 0.02 μM and wide linear range from 0.086 to 16 μM. The new method was successfully used to determine methomyl concentration in ground water indicating that the developed method can be used for the monitoring of this pesticide.