Retention characteristics of several compound classes in reversed-phase liquid chromatography with β-cyclodextrin as a mobile phase modifier

Abstract

β-Cyclodextrin was investigated as a mobile phase modifier in the reversed-phase liquid chromatography of polycyclic aromatic hydrocarbons, nitrogen hetero-cycles and hydroxyl aromatics. A wide range of β-cyclodextrin concentrations was employed, and the retention properties of the compound classes were compared in methanol—water and ethanol—water mobile phases at 25°C. β-Cyclodextrin—solute dissociation constants were obtained for the compounds in several methanol—water and ethanol—water mobile phase compositions, using the chromatographic data. The trends in the retention data and dissociation constants for the compound classes were discussed. Several conclusions were drawn concerning the mechanism of retention when β-cyclodextrin is present in the mobile phases. Also, comparisons were made between the structural features of the compounds and their capacity factors and dissociation constants.