Abstract: Via covalent coupling of epoxy group, an open tubular column covalently modified with carboxymethyl chitosan (CMC) as stationary phase was prepared. The parameters of column pretreatment, silanization and chemically bonding of CMC were optimized. The morphology of inner wall of the open tubular column was observed by scanning electron microscope (SEM), which showed that the inner wall of the prepared column was evenly coated with a polymer film. Either positive or negative electroosmotic flow (EOF) could be achieved by varying the pH values of running buffer. Good reproducibility was obtained with the relative standard deviations (RSDs) of EOF less than 0.8% for run-to-run (n=6), less than 3.5% for day-to-day (n=3), less than 4.3% for column-to-column (n=3) and less than 6.1% for batch-to-batch (n=3). Nucleotides (AMP, GMP, CMP and UMP) were analyzed on the open tubular column modified with CMC, with high column efficiencies ranging from 36000 to 182000 plates/m. The results indicate that the developed method is effective, easy and stable.

Key words: carboxymethyl chitosan, epoxy group bonding, open tubular capillary electrochromatography (OTCEC)