On-line sample concentration in micellar electrokinetic chromatography with cationic micelles in a coated capillary

The electroosmotic flow was successfully suppressed even in the presence of cationic surfactants, when a polyacrylamide-coated capillary was employed. Two on-line sample concentration techniques of sample stacking and sweepin g were evaluated in micellar electrokinetic chromatography (MEKC) using the polyacrylamide-coated capillary. Cationic surfactants were used as pseudos tationary phases in MEKC. At least 60-fold and about 600-fold increases in detection sensitivity were obtained in terms of peak heights by sample stac king and sweeping, respectively. (C) 2001 Published by Elsevier Science B.V .