No abstract

The possibilities of the decomposition by non-negative least squares (NNLS) and Multivariate Curve Resolution-Alternating Least Squares (MCR-ALS) methods of determination of spectra and concentrations of species in multicomponent (up to 8) liquid solutions by analyzing FTIR ATR and Raman spectra are discussed. It is shown that the NNLS decomposition of Raman spectra provides better results than the decomposition of the same mixture measured with the FTIR ATR method. This fact is connected with narrower width and smaller overlap of vibrational peaks obtained with the use of Raman spectroscopy comparing to IR spectroscopy for molecular liquids. It is shown that using the known spectra can increase the total number of species, for which a quantitative information can be successfully obtained. The unknown concentration profiles of an = 8-component liquid mixture can be found correctly if the − 1 spectra of pure components are used as spectral constrains during the MCR-ALS analysis.

Blood analysis by spectroscopic techniques can provide important information about biochemistry and life processes in it. Blood indices are highly variable, and plenty of factors influence them. The present work describes the combination of two methods-IR and Raman spectroscopies of blood applied to investigate gerontology issues. We carried out a pilot study of 74 blood samples. The donors were differentiated by age with the Partial Least Squares (PLS) analysis of Raman and IR spectra. Analyzing the principal component spectra obtained during PLS processn the most illustrative bands were found in the intervals 2860-3030 cm