Characterization and applications of etched chemically modified capillaries for open-tubular capillary electrochromatography

In this article, the effects of the stationary phase, buffer pH, organic mo difier type, organic modifier composition, applied voltage, and temperature on the migration of several synthetic peptides in etched chemically modifi ed open-tubular capillaries are discussed. With these solutes, migration is due to two effects: electrophoretic mobility and solute/bonded phase inter actions. In addition, relative migration rates are evaluated for the peptid e samples as a function of these experimental variables in order to determi ne which parameters might be useful for optimizing separations in open-tubu lar capillary electrochromatography (OTCEC). Some examples of synthetic pep tide separations are presented where the sample contains a major component and several minor species, demonstrating how the resolution of these mixtur es can be affected by the appropriate choice of experimental variables.