Surfactant-mediated complex formation for determination of traces amounts of zinc, cadmium, and lead with 4-(2-thiazolylazo) resorcinol and chemometric methods.

The partial least squares modeling is a powerful multivariate statistical tool applied to the spectrophotometric simultaneous determination of the divalent ions of zinc, cadmium, and lead based on the formation of their complexes with 4-(2-thiazolylazo) resorcinol in surfactant media. The linear concentration range for zinc, cadmium, and lead were 0.10-1.31, 0.148-1.92, and 0.148-3.70 mg L( -1), respectively. The experimental calibration set was composed of 36 sample solutions using a mixture design for three component mixtures. The absorption spectra were recorded from 380 through 650 nm. The effect of pH on the sensitivity in determination of zinc, cadmium, and lead was studied in order to choose the optimum pH (pH = 8) for determination. The root-mean-square errors of predictions for zinc, cadmium, and lead were 0.0466, 0.0282, and 0.050, respectively. The proposed method was successfully applied for the determination of zinc, cadmium, and lead in water samples.