Quantitative analysis of the Raman spectra of mixtures of weakly interacting components by factor analysis methods

Abstract

A system of 17 overlapped Raman spectra in the 250–350 cm^–1 spectral region of the weakly interacting component mixture of 1,2-dichloroethane, dichloromethane and carbon tetrachloride has been subjected to the statistical methods of target factor analysis (TFA) and evolving factor analysis (EFA). The results have demonstrated that concentrations of substances with intense bands are successfully determined; however, there are difficulties in analyzing weak bands of one of the components, especially when applying a TFA technique. The results of such an analysis can be improved by minimal changes in one of the coordinates of a rotation vector. Comparison of these results with a synthetic spectral model suggests that problems with analysis of weak bands are caused by the presence of a strong band that greatly overlaps the weak one.