Simultaneous determination of three organophosphorus pesticides by differential pulse stripping voltammetry and chemometrics

A differential pulse stripping voltammetry method (DPSV) is proposed for the determination of parathion-methyl (PTM), fenitrothion (FT) and parathion (PT) at a hanging mercury drop electrode (HMDE). The voltammograms of these three compounds overlap strongly, and it is difficult to determine the compounds individually from their mixtures. Quantitative analysis for each of the pesticide compounds in a mixture has been investigated with the aid of chemometrics and the prediction performance of the different methods such as classical least squares (CLS), principal component regression (PCR), partial least squares (PLS), Kalman filter (KF) and radial basis function-artificial neural networks (RBF-ANN), was compared. A set of synthetic mixtures of the three compounds was analysed by using the proposed methods, and it was found that the lowest relative prediction error (RPE) and satisfactory % recovery were achieved with the RBF-ANN procedure. The proposed method was also applied to several vegetable samples spiked with known amounts of the pesticides with satisfactory results. (C) 2004 Elsevier B.V. All rights reserved.