THE EFFECT OF COMPLEXATION ADDITIVES ON ANALYTE MIGRATION BEHAVIOR INCAPILLARY ELECTROCHROMATOGRAPHY

In capillary electrochromatography (CEC), analytes often have differen t mobilities in the mobile phase, and often are involved in multiple e quilibria. In this paper, the migration behavior of an analyte in CEC is described by a general equation in which individual capacity factor s are used to describe the tendency of the analyte to exist as the var ious analyte species present in a separation system, and the effects o f both field and equilibrium are accounted for. The resolution of two analytes is shown to be related linearly to the ratio of their migrati on rates. The effect of the electroosmotic flow (EOF) in CEC is more c omplicated than in CE because it is experienced only by a fraction of the analyte, whereas in CE, it is experienced by all analyte species. A procedure for calculating the electrophoretic mobility of the analyt e based on the fraction of the analyte in the buffer is demonstrated. The effect of the EOF on resolution is also discussed.