Abstract: A set of wide polar aromatic analytes was separated by microemulsion electrokinetic capillary chromatography(MEEKC). The effects of microemulsion compositions, including the core phases(n-hexane, n-heptane, n-octane) alkyl chain length, the concentrations of core phase heptane, surfactant sodium dodecyl sulfate and co-surfactant n-butanol, on electrokinetic separation were studied. The results showed that the surfactant had the similar effects on the retention time of all analytes. And both core phase and co-surfactant had different effects on analytes with hydrophilic functional groups and without any hydrophilic functional group. The separation mechanism of microemulsion electrokinetic chromatography was discussed. Using microemulsion consisting of 80 mmol/L n-heptane-120 mmol/L SDS-900 mmol/L n-butanol-10 mmol/Lborate, the complete separation was obtained within 14minutes. The numbers of theoretical plate ranged 3×10⁵-9×10⁵per meter.

Key words: Electrokinetic capillary chromatography, Microemulsion, Aromatic compound