External electric field control of electroosmotic flow in non-coated and coated fused-silica capillaries and its application for capillary electrophoretic separations of peptides

The influence of an external electric field on the electroosmotic flow in t he noncoated (bare) fused-silica capillaries and in the fused-silica capill aries with covalent coating of the inner surface by the polymer of a new ac rylamido derivative, N-(acryloylaminoethoxy)ethyl-beta-D-glucopyranose, has been tested in the capillary electrophoretic separations of peptide analyt es. The effect of magnitude and polarity of the external electric field on the flow-rate of the electroosmotic flow, the migration times of charged an alytes and the separation efficiency and resolution of separations of synth etic oligopeptides, diglycine, triglycine, glycyl-proline and prolyl-glycin e, by capillary zone electrophoresis has been evaluated. The effect of the external electric field on the velocity of the electroosmotic flow was much higher in the bare fused-silica capillaries than in the coated capillaries . Better separation of the analyzed peptides was achieved in the coated fus ed-silica capillaries. An external electric field proved to be an effective tool for control of the electroosmotic how and for optimization of the spe ed and resolution of capillary electrophoretic separations of synthetic pep tides. (C) 2000 Elsevier Science B.V. All rights reserved.