Abstract: Amixture of six benzene derivatives, i.e. aniline, acetophenone, o-nitrotoluene, toluene, o-xylene, o-chlorotoluene was seperated in less than 14 minutes on a 50 μm(i.d.)×37 cm/30 cm capillaries column packed with 3 μm ODS-silica in the CH₃CN-H₂O-Tris(HCl) buffer by reversed-phase capillary electrochromatography(RP-CEC). The effects of acetonitrile concentration(φ =50%～80%), electrolyte concentration(1～20 mmol/L) and pH(3～10) on the electroosmotic flow(EOF), and the retention behavior of analytes was investigated. A study of the reproducibility of the packed column was performed. The relative standard deviations for the retention time and capacity factor were lower than 1% and 1.5%.

Key words: Reversed-phase capillary electrochromatography, Benzene derivatives, Seperation behaviour, Electroosmotic flow