A novel kind of preparative electrochromatography

namely hydroxylapatite electrochromatography (HEC)

is proposed in which an electric potential is applied to the compartment packed with hydroxylapatite. In the present study

the effects of electric migration

including the electrophoresis of protein and the electroosmosis of solvent

on the separation performance of HEC are experimentally investigated. Electroosmotic fluxes of membrane

membrane and packed medium are determined and the driving forces by electoosmotic flux of membrane and packed medium are interpreted

respectively. An increase in electroosmotic flux is obtained in response to the increase in electric field strength and the decrease in ionic concentration of the buffer. The breakthrough curves obtained in the presence of an electric field show an enhanced adsorption of BSA on hydroxylapatite in terms of available bed volume for adsorption and dynamic adsorption capacity. When the elution of BSA from hydroxylapatite is conducted with the buffer of high salt concentration

the enhancement of mass transfer is mainly contributed by electrophoresis. In this case the suitable selection of polarity of electric field is essential to resolution. When elution is done with the buffer of low salt concentration

the contribution of electroosmotic flux to mass transfer becomes significant. The above results show that the application of electric field to hydroxylapatite chromatography

as shown by HEC

greatly improves its separation throughput and efficiency.