DIRECT CONTROL OF ELECTROOSMOSIS AND RETENTION WINDOW IN MICELLAR ELECTROKINETIC CAPILLARY CHROMATOGRAPHY

The zeta potential and the electroosmotic flow in micellar electrokine tic capillary chromatography (MEKC) can be directly controlled by usin g a radial electric potential gradient across the capillary wall. In t his study, the separations of neutral phenylthiohydantoin amino acids as the model system in MEKC with direct control of electroosmosis and retention window are presented. Significant enhancement in the separat ion resolution of phenylthiohydantoin amino acids under the direct con trol of electroosmosis is demonstrated.