Microemulsion electrokinetic chromatographic separation of antipyretic analgesic ingredients

Microemulsion electrokinetic chromatographic (MEEKC) separations of caffeine, aminopyine, phenobarbital and phenacetin were studied using three different core phases. The effects of core phase on migration time and efficiency are discussed. The reproducibility using octane as the core phase is better than that using heptane or 1-butyl chloride. This may be explained in terms of microemulsion stability. Using a microemulsion consisting of 80 mM octane-120 mM sodium dodecyl sulphate-900 mM 1-butanol-10 mM borate, the R.S.D. of the migration time was less than 0.8% and that of the peak area was less than 3% (n = 6). The effect of core phase concentration on separation was also investigated.