EFFECTS OF MICROEMULSION COMPOSITION ON MICROEMULSION ELECTROKINETIC CAPILLARY CHROMATOGRAPHY

A set of wide polar aromatic analytes was separated by microemulsion e lectrokinetic capillary chromatography (MEEKC). The effects of microem ulsion compositions, including the core phases(n-hexane, n-heptane, n- octane) alkyl chain length, the concentrations of care phase heptane, surfactant sodium dodecyl sulfate and co-surfactant n-butanol, on elec trokinetic separation were studied. The results showed that the surfac tant had the similar effects on the retention time of all analytes, An d both core phase and co-surfactant had different effects on analytes with hydrophilic functional groups and without any hydrophilic functio nal group. The separation mechanism of microemulsion electrokinetic ch romatography was discussed, Using microemulsion consisting of 80 mmol/ L n-heptane-120 mmol/L SDS-900 mmol/L n-butanol-10 mmol/L borate, the complete separation was obtained within 14 minutes. The numbers of the oretical plate ranged 3 X 10(5)-9 X 10(5) per meter.