Capillary electrochromatography of derivatized mono- and oligosaccharides

An octadecyl-silica (ODS) stationary phase with light surface coverage of octadecyl ligands was introduced for capillary electrochromatography (CEC) at moderate electroosmotic flow (EOF) velocity. The ODS stationary phase was intentionally produced with light surface coverage in order to ensure a moderate EOF velocity across the packed capillary column, thus allowing relatively rapid analysis time. Despite the fact that the stationary phase leaves 75% of the surface silanols unreacted, fused-silica capillary columns packed with this ODS stationary phase exhibited reversed-phase behavior toward neutral alkylbenzene homologous solutes using hydroorganic eluents. Closely related p-nitrophenylglycosides including some p-nitrophenyl-monosaccharides and p-nitrophenyl-maltooligosaccharides were readily separated on the ODS capillary column within a relatively short analysis time. Also, alpha- and beta-anomers of some p-nitrophenyl-monosaccharides were readily separated in the presence of a small amount of borate buffer in the hydroorganic eluent.