Multicomponent determination of atrazine, diuron and chlorpyrifos in groundwaters and soils by spectrophotometry using multivariate calibration

Three multivariate calibration methods, partial least squares (PLS-1 and PLS-2) and principal component regression (PCR), were applied to the simultaneous determination of the three pesticides atrazine, diuron and chlorpyrifos, in mixtures, by ultraviolet–visible absorption spectrophotometry. The absorption and first-derivative absorption spectra of the ternary mixtures were used to perform the optimization of the calibration matrices by the PLS and PCR methods. The results obtained by the application of the different chemometric approaches are discussed and compared. No significant advantages were found for the prior differentiation step. The proposed method was applied satisfactorily to the determination of atrazine, diuron and chlorpyrifos in groundwaters and soils.