Retention of Cyclodextrins under the Conditions of Reversed-Phase Chromatography and Determining the Stability Constants of Inclusion Complexes of Antocyanins with β-Cyclodextrein

Abstract

The chromatographic behavior of α, β, and γ-cyclodextrins on three types of reversed-phase chromatography of stationary phases—С4, С8, and С18—is investigated. Patterns of sorption are determined experimentally, and modeling is used to determine the nature of interaction between cyclodextrins and grafted phases. Based on the obtained results and considering experiments on the formation of a complex of β-cyclodextrin and n-hexane, it is suggested that the probability of modifying surfaces of the C4 phase with cyclodextrins in aqueous–acetonitrile mobile phases with low contents (from 5 vol %) of organic modifier is low, and the C18 phase could be used without surface modification of the sorbent when the acetonitrile content is above 10 vol %. To corroborate these conclusions, the constants of complex formation of β-cyclodextrin with some anthocyanins are determined by adding β-cyclodextrin to the mobile phase under the conditions of chromatography on the C4 phase; the same is impossible using the C18 phase.