Potential of flow-counterbalanced capillary electrophoresis for analytical and micropreparative separations

The potential of flow-counterbalanced capillary electrophoresis (FCCE) in chiral and achiral separations was investigated in this work. Unlimited increase of the separation selectivity can be achieved for binary mixtures using FCCE. This was shown for the enantioseparation of (+/-)-chlorpheniramine (CHL) with carboxymethyl-beta-cyclodextrin (CM-beta-CD) as chiral selector. The other example is the separation of alpha- and beta-isomers of a dipeptide aspartame (AS). The carrier ability of the (chiral) selector or pseudostationary phase, the electroosmotic flow (EOF), the pressure-driven flow or hydrodynamic flow can be used as a counterbalancing flow to the electrophoretic mobility of the analyte or vice versa. This mechanism can also be used for micropreparative purposes. FCCE also bears the potential for stepwise separation and fraction collection of multicomponent mixtures.