ACHIRAL SELECTIVITY IN CYCLODEXTRIN-MODIFIED CAPILLARY ELECTROPHORESIS

Torus-shaped, circular, and hydrophilic cyclodextrins (CD) have been f requently used in capillary electrophoresis (CE) as buffer modifiers t o effect chiral separation of enantiomers of drugs and specialty chemi cals. Although less common, both neutral and charged cyclodextrins hav e also been exploited in CE to optimize the achiral separations of pep tides, proteins, small molecules and a variety of positional isomers. Nonionic CDs are only useful for separations of net charged analytes t hrough judicious partitioning of such guest molecules into their hydro phobic cavity of the former. However, they can be used with a surfacta nt for an effective resolution of neutral solutes as a result of a dif ferential partitioning of such solutes in the micellar and the cyclode xtrin-modified buffer phase. Ionic cyclodextrins, particularly, negati vely charged derivatives with their own electrophoretic mobilities, in crease the separation window and enable better resolution of analytes which weakly complex with or are poorly differentiated by neutral cycl odextrins. (C) 1997 Elsevier Science B.V.