MODELING ELECTRORETENTION OF PROTEINS DURING ELECTROPOLARIZATION CHROMATOGRAPHY

An attempt is made to extend the understanding of electropolarization chromatography (EPC) by consideration of the nonlinear effects which dominate the system behavior for high polarizing fields. Of particular interest is the phenomenon of electroretention, a total immobilization of any protein above a finite, species-dependent, critical field strength. The modeling effort appears to have clarified the effects of high fields on many aspects of EPC, particularly the decrease in retardation with an increase in protein loading. It is unsuccessful in explaining electroretention because our model insufficiently predicts high degrees of concentration polarization. The basic reasons for this underestimation of polarization are not yet known, but they most probably reflect inadequate knowledge of transport and thermodynamic behavior of concentrated protein solutions. It is, however, also possible that the description of small-ion diffusion is oversimplified. Other effects like electroosmotic drying and a nonlinear electric field may also play a role in electroretention. It is recommended that further effort should be devoted primarily to the collection of transport and thermodynamic data of proteins at high concentrations, and systematic empirical investigation of this phenomenon.Copyright © 1979 by Marcel Dekker, Inc.