INDIRECT VOLTAMMETRIC DETERMINATION OF CARBARYL AND CARBOFURAN USING PARTIAL LEAST-SQUARES CALIBRATION

A differential pulse voltammetric method is proposed for the determination of the carbamate pesticides carbaryl and carbofuran, based on the anodic peaks observed following their alkaline hydrolysis (formation of phenol derivatives). Linear relationships between the oxidation peaks and concentration were obtained in the ranges 5 x 10(-7) to 10(-4) M for carbaryl and 5 x 10(-7) to 5 x 10(-5) M for carbofuran, the relative standard deviations being 1.62 and 1.86%, respectively. The method was applied to the determination of these compounds in formulations. Different chemometric methods (PLS-1, PLS-2 and CLS) were examined for the resolution of the overlapped peaks of both compounds and their determination in mixtures. The best results were obtained with the PLS-1 method, which was applied to determine both compounds in river water samples.