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 modifier type, organic modifier composition, applied voltage, and temperature on the migration of several synthetic peptides in etched chemically modified open-tubular capillaries are discussed. With these solutes, migration is due to two effects: electrophoretic mobility and solute/bonded phase interactions. In addition, relative migration rates are evaluated for the peptide samples as a function of these experimental variables in order to determine which parameters might be useful for optimizing separations in open-tubular capillary electrochromatography (OTCEC). Some examples of synthetic peptide separations are presented where the sample contains a major component and several minor species, demonstrating how the resolution of these mixtures can be affected by the appropriate choice of experimental variables.