Rapid monitoring of fungicide fenhexamid residues in selected berries and wine grapes by square-wave voltammetry at carbon-based electrodes

A completely new electroanalytical method for the determination of fenhexamid (FNX) residues in fruit samples has been developed. This method is based on anodic oxidation of fungicide in Britton-Robinson buffer (pH 4) containing 10% (v/v) methanol using square-wave voltammetry when five different carbon-based electrodes were tested. An electrochemical behaviour of FNX was studied on a glassy carbon electrode using cyclic voltammetry, while glassy carbon paste electrode was selected for analytical purposes. Linear range for FNX from 3.96 to 49.50 µmol L^-1 characterized by coefficient of determination of 0.9964, sensitivity of 0.176 µA L µmol^-1_, and detection limit of 1.32 µmol L^-1 were calculated. Results acquired from analyses of blueberries and wine grapes were compared to those obtained by a reference chromatographic method, and a satisfactory agreement has been reached. Finally, it seems that the present voltammetric approach could find its application in food quality control as screening assay.

Keywords: Carbon-based electrodes; Fenhexamid; Food safety; Pesticides; Square-wave voltammetry.