Simultaneous spectrophotometric determination of four metals by the kernel partial least squares method

Simultaneous determination of Mn, Zn, Co and Cd was studied by two methods, classical partial least squares (PLS) and kernel partial least squares (KPLS), with 2-(5-bromo-2-pyridylazo)-5-diethylaminephenol (5-Br-PADAP) and cetyl pyridinium bromide (CPB). Two programs, SPGRPLS and SPGRKPLS, were designed to perform the calculations. Eight error functions were calculated for deducing the number of factors. Data reductions were performed using principal component analysis. The KPLS method was applied for the rapid determination from a data matrix with many wavelengths and fewer samples. Experimental results showed both methods to be successful even where there was severe overlap of spectra.