Plate-height equation for non-linear chromatography

Abstract

A height equivalent to a theoretical plate (HETP) equation for non-linear chromatography was derived analytically based on an equilibrium—non-equilibrium theory. The band-broadening factors including non-linear behaviour of the adsorption isotherm and kinetics of adsorption—desorption and mass transfer were all considered. The contributions of sample concentration, inhibitor concentration and sample size to plate height were explicitly expressed. Some significant advantages of the proposed plate-height equation were demonstrated by the agreement between the experimental data from a concanavalin A—sugar system and the calculated results. In a limiting case, this plate-height equation can reduce to the HETP expression for linear chromatography. It is easier to use this HETP equation in scaling-up a non-linear chromatographic process and in determining the thermodynamic and kinetic constants characterizing non-linear chromatography.