Quantitative spectral analysis of multicomponent equilibria

A generalization is presented of a method for the determination of equilibrium constants for binary mixtures. It is shown that titrations involving several components can be quantitatively characterized in terms of component concentrations and spectral responses, even when none of the component spectra is known and the components cannot be obtained in pure form. The method is efficient even if the component spectra overlap extensively. It is applicable to all spectroscopic techniques that provide a linear response, opening up new possibilities to analyze complex chemical systems. The approach is illustrated by determining the absorption spectra and protolytic constants for the fluorescein protolytic equilibria.