Plate-model applied on concentration effects in size exclusion chromatography

Abstract

A universal procedure of modeling chromatography separation, based on the plate model, has been developed. On each plate, the equilibrium between the analyte in the mobile and stationary phases is established. This equilibrium may be described by the concentration-dependent partition coefficient. The establishment of the equilibrium on each plate is followed by the displacement of the analyte in the mobile phase by one plate, establishment of new equilibrium, etc. The result is a series of elution curves with positions of maxima dependent on injected mass of the polymer. The procedure has been tested on modeling concentration effects on the basis of dependences of the partition coefficient on local concentrations on each plate. By comparison with the experiment, the slope of the concentration dependence of the partition coefficient of polystyrene in benzene was estimated. It is in qualitative agreement with the literature data obtained by a computer simulation of chromatography separation of polymers in good solvents.