ENHANCEMENT OF THE SEPARATION SELECTIVITY OF A GROUP OF POLYCYCLIC AROMATIC-HYDROCARBONS USING MIXED CYCLODEXTRIN-MODIFIED MICELLAR ELECTROKINETIC CHROMATOGRAPHY

The separation selectivity of a group of twenty polycyclic aromatic hy drocarbons (PAHs) (including sixteen Environmental Protection Agency p riority PAHs) was studied when mixtures of native beta- and gamma-cycl odextrins (CDs) are used as modifiers in the separation buffer in cycl odextrin-modified micellar electrokinetic chromatography. The ratio be tween the concentrations of beta- and gamma-CDs in the separation buff er as well as the total concentration was varied for various buffer co ncentrations. An enhancement in selectivity was obtained which enabled the separation of eighteen PAHs when using a 0.140-M berate buffer (p H 9) containing 0.100 M sodium dodecyl sulphate micelles, 0.042 M beta -CD, 0.020 M gamma-CD and 2.5 M urea. The correlation between the loga rithm of the capacity factors of PAHs and the logarithm of their octan ol-water distribution coefficients was also investigated. (C) 1997 Els evier Science B.V.