J. Ghasemi et A. Niazi, Simultaneous determination of cobalt and nickel. Comparison of prediction ability of PCR and PLS using original, first and second derivative spectra, MICROCHEM J, 68(1), 2001, pp. 1-11
Two multivariate calibration methods, partial least squares (PLS) and princ
ipal component regression (PCR), were applied to the simultaneous determina
tion of the divalent ions of nickel and cobalt based on the formation of th
eir complexes with 4-(2-pyridylazo) resorcinol (PAR). The original, first a
nd second derivative absorption spectra of the binary mixtures were used to
perform the optimization of the calibration matrices by the PLS and PCR me
thods. The results obtained by the application of the different chemometric
approaches are discussed and compared. The Savitzky-Golay convolution meth
od is used for calculating the first- and second-derivative absorption spec
tra of binary mixtures. Calibration matrices were 15-540 and 15-560 ng ml(-
1) for cobalt and nickel, respectively. (C) 2001 Elsevier Science B.V. All
rights reserved.