SEPARATION OF BASIC-PROTEINS AND PEPTIDES BY CAPILLARY ELECTROPHORESIS USING A CATIONIC SURFACTANT

Incorporation of a low concentration of cetyltrimethylammonium bromide (CTAB) in the running electrolyte is shown to dynamically coat the si lica capillary and to reverse the direction of electroosmotic flow. Th e CTAB coating prevented interaction of proteins with the capillary su rface and enabled sharp peaks to be obtained in the electropherograms. A systematic study of experimental parameters demonstrated the import ance of selecting a suitable buffer electrolyte and an appropriate pH, Excellent separations were obtained for five proteins, three enkephal ins, and six dipeptides with an efficiency of approximately 500,000 th eoretical plates per meter. The method developed is very simple to per form and was found to give excellent reproducibility.