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 electroosmo tic pump can all affect the migration time of an analyte in a capillary ele ctrophoretic system. We report here a systematic study of the effects of va riations in these parameters upon practical ionic separations, especially a s applied to a suppressed conductometric capillary electrophoretic separati on 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 comparab le results except for late-eluting ions for which the latter technique clea rly yields higher efficiencies. (C) 1999 Elsevier Science B.V. All rights r eserved.