▎ 摘　　要

A nanocomposite sensor based on Ag-ZrO2 nanoparticles and graphene was fabricated and employed for electrocatalytic detection of fenitrothion. Improved electrocatalytic activity of the sensor was demonstrated by cyclic voltammetry and impedance techniques. In fenitrothion, electrochemical reduction of the nitro group to hydroxylamine was found to be irreversible, adsorption-controlled, and pH dependent. Improved voltammetric peak signals for fenitrothion were obtained due to the synergistic effect of silver and zirconia nanoparticles over graphene support. Square wave adsorptive stripping voltammetric method was developed for highly sensitive determination of fenitrothion. Working conditions such as pH, accumulation potential, accumulation time, square wave frequency, square wave amplitude, and scan rate were optimized with respect to maximum and well-defined peak signals. Wide linear range was observed between the peak signals and concentration of fenitrothion over the range 0.1-100 nM with a detection limit of 0.56 nM. The proposed stripping voltammetric protocol is readily applied for the determination of fenitrothion in well water and soil samples with good recoveries.