ELECTROPHORETIC SEPARATION OF PROTEINS ON DYNAMICALLY TREATED FUSED-SILICA CAPILLARIES

CZE is a very useful tecnique for protein analysis, but some difficult s are encountered for their strong adsorption on the negatively charge d. silica walls. The static deactivation of capillaries via polymeric coating is very laborious and generally problematic (because of the ca pillary clogging and short life). The dynamic deactivation is very fas t and good separation can be reached. In this work we have investigate d the separation of basic proteins using as deactivating solution the background electrolyte containing a polyamine or a surfactant.The poly amine, when protonated, is attracted from the negatively charged capil lary walls which are neutralized. The following polyamines: 1,3 diamin opropane, bis-(3-aminopropyl)amine, triethylenetetramine and the catio nic surfactant cetyltrimethylammonium bromide were tested. Each of the se compounds is able to deactivate the fused silica capillary and the electroosmotic flow can be decreased and even reversed. In the best wo rking conditions well resolved and symmetrical peaks are obtained. The RSD% of migration times is about 1%.