Application of the partial least-squares calibration method to the simultaneous kinetic determination of propoxur, carbaryl, ethiofencarb and formetanate

Abstract

A method based on the application of partial least-squares analysis to bilinear data was used for the simultaneous determination of propoxur, carbaryl, ethiofencarb and formetanate by a kinetic–spectrophotometric method. The procedure is based on the different rate constants of the reactions between p-aminophenol, in the presence of potassium metaperiodate, and the phenolic and naphtholic compounds obtained from the alkaline hydrolysis of the pesticides using a stopped-flow injection procedure. Mixtures containing 2–10 µg ml^–1 of propoxur, 2–8 µg ml^–1 of carbaryl, 2–10 µg ml^–1 of ethiofencarb and 2–10 µg ml^–1 of formetanate were successfully resolved with errors of less than 5%.