An analysis, based on established theory, of mixed-solvent behaviour in gas–liquid chromatography

Abstract

Seven published sets of results on gas–liquid chromatographic mixed-solvent systems yield data on nearly two hundred ternary liquid systems and these were analysed for conformity with the Scatchard–Hildebrand–Flory–Huggins model of liquid mixtures. Whilst the expected quadratic (ln K_R, φ) relation applies in most cases, consistent values of solvent–solvent interaction parameters are not obtained when specific solute–solvent attractions exist. The use of alkane solutes appears to give constant and meaningful values of these parameters even when specific solvent–solvent interaction occurs. A computed simulation of solute-additive complexing in a solvent medium shows a linear (K_R, c) relation at relatively low additive concentration but indicates that any calculation of formation constants by this method must involve very considerable quantitative uncertainty.