VAN DEEMTER PLOT IN HIGH-SPEED COUNTERCURRENT CHROMATOGRAPHY WITH A FIXED VOLUME OF STATIONARY PHASE

Abstract

An adaptability of countercurrent chromatographic data to Van Deemter equation (H = A + B/u + Cu) is examined under a fixed volume of the stationary phase. Three test samples, epigallochatechin gallate (EGCG), gallocatechin-gallate (GCG), and epicatechin gallate (ECG) were separated using a two-phase solvent system of n-hexane/ethyl acetate/water (3.5:1:10, v/v/v) at various linear flow rates (u). Our mathematical treatment produced a set of formulae, HEGCG = 6.5 + 1/u + 6u; HGCG = 6.5 + 1.3/u + 7u; and HECG = 6.5 + 2.5/u + 9u, which showed excellent fit to the experimental data for each component. Constants B and C show high correlation with the partition coefficient values of three components. Based on the high correlation between log u and log H when u > 1, the plate height (H) for three components may be expressed by H = Duk, where D is the plate height at u = 1 cm/s and k, the constant for each component.