Effects of separation potential, hydrostatic pressure and auxiliary electroosmotic pumping on a suppressed conductometric capillary electrophoresis separation system

The separation potential, hydrostatic pressure and an auxiliary electroosmotic pump can all affect the migration time of an analyte in a capillary electrophoretic system. We report here a systematic study of the effects of variations in these parameters upon practical ionic separations, especially as applied to a suppressed conductometric capillary electrophoretic separation system (SuCCESS). Under conditions that are held constant during a run, auxiliary electroosmotic pumping generally produces the best results. When the parameter is changed during the run in a manner reminiscent of gradient elution in chromatography, under the optimum condition for each, gradient separation potential and auxiliary electroosmotic pumping produces comparable results except for late-eluting ions for which the latter technique clearly yields higher efficiencies. (C) 1999 Elsevier Science B.V. All rights reserved.