Application of chemometrics methods for the simultaneous kinetic spectrophotometric determination of aminocarb and carbaryl in vegetable and water samples.

A procedure for the simultaneous kinetic spectrophotometric determination of aminocarb and carbaryl in vegetable and water samples was described. The method was based on the differential oxidation rate of aminocarb and carbaryl when they were reacted with the oxidant, potassium ferricyanide (K(3)Fe(CN)(6)), in an appropriate alkaline medium. Both species were instantly oxidized, and resulted in a decrease of ferricyanide concentration. This anion has a maximum spectral absorbance at about 420 nm. Under the optimum experimental conditions, the linear ranges were 0.05-0.6 mg L(-1) and 0.1-1.2 mg L(-1) for aminocarb and carbaryl, respectively. The kinetic data collected were processed by chemometrics methods, such as classical least squares (CLS), partial least squares (PLS), principal components regression (PCR), back propagation-artificial neural network (BP-ANN), radial basis function-artificial neural network (RBF-ANN), and principal component-radial basis function-artificial neural network (PC-RBF-ANN). These methods were applied for the prediction of the two carbamate pesticides. The results showed that the PLS and PC-RBF-ANN calibration models gave the lowest prediction errors. The proposed method was successfully applied to the simultaneous determination of aminocarb and carbaryl in vegetable and water samples, and satisfactory results were obtained.