Enantiomeric separation by capillary electrophoresis with an electroosmotic flow-controlled capillary

Perfect control of electroosmotic flow (EOF) was achieved by dovetailing su ccessive multiple ionic-polymer layer (SMIL) coated capillaries. The direct ion and magnitude of the EOF was perfectly controllable over the pH range 2 -13. Zone diffusion was not observed, even if the inner wall of the dovetai led capillary was discontinuous, or if the sample zone passed through the c onnected part of the capillary because the RSDs of migration time, theoreti cal plates, symmetry factor and SIN of the marker were almost the same when seamless capillary and dovetailed capillary were compared. The dovetailed capillary was applied to cyclodextrin modified capillary zone electrophores is. The control of the EOF enabled us to control both the resolution and th e migration order of the enantiomers. The migration time was also controlla ble and, therefore, the best condition between separation and migration tim e could be determined by controlling the EOF. Partial filling affinity elec trokinetic chromatography with a protein used as a chiral selector was also studied. The migration of the pseudo-stationary phase was controllable by EOF, and detection of the solute at 214 nm was possible. Therefore, the EOF -controlled dovetailed capillary has great potential to expand the applicat ion of the separation technique. (C) 2000 Elsevier Science B.V. All tights reserved.