SELECTIVITY IN CAPILLARY ELECTROPHORESIS IN THE PRESENCE OF MICELLES,CHIRAL SELECTORS AND NONAQUEOUS MEDIA

In addition to high efficiency, short analysis times and small sample volumes, a further attractive feature of capillary electrophoretic tec hniques is the possibility to achieve high selectivities. Usually, sel ectivity control also allows improvement in the resolution. A simple w ay to enhance the selectivity of capillary electrophoretic separations is to add one or more surfactants above their critical micelle concen tration, or in the case of chiral separations to add a chiral selector to the background electrolyte. Because of the dynamic structure of mi celles, the aggregation of monomers and size of the micelles can be ea sily adjusted. This review describes the various types of surfactants used in micellar electrokinetic capillary chromatography, and the chir al selectors employed in enantiomeric separations by capillary electro phoresis. Factors affecting the selectivity are noted. A brief discuss ion is included of the selectivity enhancement obtainable in non-aqueo us media. (C) 1997 Elsevier Science B.V.