A Theoretical and Experimental Study of Counteracting Chromatographic Electrophoresis

Abstract

Counteracting chromatographic electrophoresis (CACE) is a separation process that combines gel chromatography with electrophoresis. This process, originally developed by O'Farrell1, may be used for protein separation by causing a specific protein to accumulate at the interface between two bed packings of different internal porosity. In this paper a theoretical model for CACE has been developed. This model gives an accumulation criterion that specifies the operating conditions (i.e. applied field and flow rates), and the bed and protein parameters (i.e. external bed porosity, internal particle porosity, protein free mobility, and the ratio of the protein mobility in the get to that in free solution) that lead to accumulation in the column. This accumulation criterion was tested with experimental data for the accumulation of the colored proteins ferritin, myoglobin, and cytochrome-c. This data fit the criterion fairly well for all three proteins. The theoretical model was extended to consider the transient accumulation at the interface between the packings in the column for the batch process where no product was removed from the interface, and for the continuous process where product was continuously removed from this interface. A critical value of the operating parameter lμl (i.e. the ratio of the electrical migration to the convective flow) was found to give the fastest approach to steady-state for the continuous process.