Chemometric methods for determination of selective regions in diode array detection high performance liquid chromatography of mixtures: application to chlorophyll a allomers

Abstract

The diode array detection HPLC traces of a mixture of allomeric degradation products of chlorophyll a was analysed in detail. Up to nine possible closely eluting components with fairly similar spectral characteristics can be identified. Several methods for determining the composition of one or selective regions of the chromatogram are described, including principal component scores plots, derivatives, fixed window factor analysis, expanding window factor analysis, peak ratio plots and spectral similarity indices. Spectral similarity plots appear to be the most informative provided that reference spectra of potential pure standards are available. In the case cited, peak ratio plots are also useful. Scaling is shown to be important in scores plots.