Abstract: A hydrophilic monolithic column was prepared by in-situ polymerization of 2-hydroxyethyl methacrylate (HEMA) as a functional monomer and ethylene glycol dimethacrylate (EDMA) as a cross-linking agent in the fused-silica capillary. The monolithic column was evaluated as a hydrophilic interaction capillary electrochromatography (HI-CEC) stationary phase for polar solutes. The polar sites on the surface of the monolithic stationary phase responsible for hydrophilic interactions were provided from the hydroxy groups on the surface of the monolithic stationary phase. These polar functionalities also attract ions from the mobile phase and impart the monolithic stationary phase with a given zeta potential to generate electro-osmotic flow (EOF). The characterization and the performance of the poly(HEMA-co-EDMA) monolithic column were carried out. The electrochromatographic retention behaviors of polar solutes were investigated and the retention mechanism was also studied. Hydrophilic interaction was observed at high acetonitrile content (＞62%, v/v). The results also show that the monolithic column can effectively separate polar solutes including phenols, benzoic acids, anilines, nucleosides and nucleic acid bases under HI-CEC mode.

Key words: hydrophilic interaction, polymer-based monolithic column, capillary electrochromatography (CEC)