Modern Theory for Multicomponent Ion Exchange Equilibria and Chromatographic System Behavior in Columns

Abstract

Theoretical description, including computerized simulation of the dynamic behavior of multi-component ion exchange (IEx) chromatographic systems for the displacement-elution regime in column is presented. Multi-component IEx equilibria used for the simulation of IEx dynamics have been described by the modern theoretical approach called by the German authors as the “Surface Complexation Theory” (SCT-Model). The main proposal in the SCT-Model is that the fixed groups of any ion exchanger form Surface Complexes with counter-ions of the components. By computerized simulation the dynamic behavior of the multi-component concentration waves formed by the displacer ions (H+ or Na+) including two various components Me1 + and Me2 + eluted during the displacement-elution dynamics in the IEx columns is analyzed. The term “wave” reflects one of the fundamental concepts applied in the theory of chromatography.[1–3] The behavior depends on SCT-parameter values, used in the SCT-Model for multi-component equilibria. The experimental SCT-parameters obtained previously for a number of ion exchangers are used for the computerized simulation of the dynamic processes on the basis of differential mass balance equations.