Effect of salt concentration on the elution properties of complexes formed between sodium dodecylsulphate and protein polypeptides in high-performance silica gel chromatography

Abstract

Complexes formed between sodium dodecylsulphate and protein polypeptides were applied to high-performance silica gel (TSK-GEL G3000SW) chromatography at various concentrations of sodium phosphate buffer of pH 7. The retention time was markedly dependent on the buffer concentration, and the resolution of protein polypeptides was satisfacory only at buffer concentratins between 0.05 and 0.15 M. The effect of buffer concentration could be ascribed only partially to the change in the effective size of the complexes, having a polyelectrolyte-like nature, with salt concentration. It is suggested that the ionic exclusion effect due to the negatively charged matrix of the silica gel must be taken into consideration when interpreting the phenomenon.