ELECTROPHORESIS OF PROTEINS IN UNCOATED CAPILLARIES WITH AMINES AND AMINO-SUGARS AS ELECTROLYTE ADDITIVES

The effect of triethylamine and triethanolamine in the running electrolyte on the electroosmotic flow and the migration of four standard basic proteins in bare fused-silica capillaries was examined. At pH 2.5 the direction of the electroosmotic flow was anodal with both additives and at constant ionic strength its magnitude increased with increasing additive concentration. The observations are in qualitative agreement with a theoretical model which is based on the Gouy-Chapman-Stern theory and incorporates a Langmuir-type relationship and also the Von Smoluchowski expression for the electroosmotic mobility, with the approximation to identify the zeta potential with the potential at the Stern plane. From the independence of the electrophoretic mobilities of the additive concentration and type the absence of interactions between the four basic proteins and the two alkylamines is inferred. The utility of glucosamine and galactosamine as additives for the capillary electrophoresis of basic proteins is also demonstrated and their effectiveness is compared with that of the alkylamines.