Two multivariate strategies applied to three-way kinetic spectrophotometric data for the determination of mixtures of the pesticides carbaryl and chlorpyrifos

A. ESPINOSA MANSILLA, A. MUÑOZ DE LA PEÑA, H. GOICOECHEA AND A. OLIVIERI

APPLIED SPECTROSCOPY

Society for Applied Spectroscopy

Lugar: New York; Año: 2004 vol. 58 p. 83 - 90

0003-7028

Two pesticides, carbaryl and chlorpyrifos, have been simultaneously determined using second-order kinetic spectrophotometric measurements upon alkaline oxidative degradation. In spite of the complexity of the system and of the serious spectral overlap among the reagents and products, calibration and prediction is possible thanks to the power of second-order multivariate techniques. Strategies such as parallel factor analysis (PARAFAC) and multivariate curve resolution coupled to alternating least-squares (MCR-ALS) have been employed, which adequately exploit the second-order advantage. They allow for a correct determination of the analytes both in synthetic binary samples and in a commercial formulation, in this latter case even in the presence of unmodelled interferents. Multi-way partial least-squares (n-PLS) produced good results only on synthetic binary mixtures, but failed on the commercial sample