Abstract: The effect of the addition of normal C1—C5 alcohols on the background electrolyte on the separation of a set of wide polar aromatic hydrocarbons in micellar electrokinetic capillary chromatography(MECC) was examined. Experiments were carried out with the micellar solution system of sodium dodecyl sulfate borate at pH 9.2, containing different amount(0—15%) of C1—C5 alcohols separately. For the shorter alkyl chain C1—C3 alcohols, as the content of alcohol increased, the elution window(t_m/t₀) increased, and the capacity factors(k') of all test samples decreased. Comparatively, C4 and C5 alcohols had the different effects. With the content increased the t_m/ t₀ increased first and then decreased, and the k' increased for the most solutes. The results also showed that the alcohol additives had more effect on weakly polar or hydrophobic compounds than more polar compounds. The addition of alcohol caused the increase of both the number of theoritical plates(N) and the resolution, especially for the hydrophobic compounds.

Key words: Capillary electrophoresis, Micellar electrokinetic chromatography, Normal alcohol, Modifier