Simultaneous quantitative analysis of overlapping spectrophotometric signals using wavelet multiresolution analysis and partial least squares

The mathematical bases and program algorithms of discrete wavelet transform (DWT), multiresolution and Mallat's pyramid algorithm were described. The multiresolution analysis (MRA) based on Daubechies orthogonal wavelet basis was studied as a tool for removing noise and irrelevant information from s pectrophotometric spectra. After wavelet MRA pre-treatment, eight error fun ctions were calculated for deducing the number of factors. A partial least squares based on wavelet MRA (WPLS) method was developed to perform simulta neous spectrophotometric determination of Fe(II) and Fe(III) with overlappi ng peaks. Data reduction was performed using wavelet MRA and principal comp onent analysis (PCA) algorithm. Two programs, SPWMRA and SPWPLS, were desig ned to perform wavelet MRA and simultaneous multicomponent determination. E xperimental results showed the WPLS method to be successful even where ther e was severe overlap of spectra. (C) 2000 Elsevier Science B.V. All rights reserved.