Method development of adsorbed stationary phase open tubular capillary electrochromatography

The adsorption effect of capillary wall, which was usually considered as a troublesome factor, has been used as driving force for preparing stationary phase for open tubular capillary electrochromatography (OTCEC). A number of compounds have been applied as stationary phase materials, which include cationic surfactants such as cetyltrimethylammonium bromide (CTAB), basic proteins such as lysozyme and cytochrome C, basic peptides such as Lys-Tyr and Lys-Ser-Tyr, and basic amino acid L-lysine. The adsorbed CTAB phase is used for separation of neutral compounds while other adsorbed stationary phases are used for chiral separation. The run-to-run reproducibility of retention time is rather good with RSD values less than 2.3%. The separation efficiency is excellent with the highest theoretical plate number of up to 590,000/m and the average plate number of more than 250,000/m. Being stored at 2-8 degrees C in refrigerator, the adsorbed stationary phase can last at least one month.