Separation of PAHs by Capillary Electrophoresis with Laser-Induced Fluorescence Detection Using Mixtures of Neutral and Anionic β-Cyclodextrins

For the first time, the principle of separation of neutral polynuclear aromatic hydrocarbons (PAHs) by capillary electrophoresis (CE) through the addition of cyclodextrin mixtures to the CE buffer phase was illustrated. Two neutral forms, hydroxypropyl-β-cyclodextrin and methyl-β-cyclodextrin, and two negatively charged forms, carboxymethyl-β-cyclodextrin and sulfobutyl ether-β-cyclodextrin, were used to demonstrate the principle of separation based on differential partitioning of analytes between the cyclodextrins. Methods were developed for separation of a mixture of PAHs, containing phenanthrene, anthracene, pyrene, chrysene, benzo[o]pyrene, and benzotelpyrene, using various concentration ratios of the neutral and charged cyclodextrins. The cyclodextrin mixtures provided much better separation of PAH isomers, including benzotelpyrene and benzotelpyrene, than has been reported previously using CE. In addition, there was significantly reduced sensitivity to operating parameters such as temperature and applied potential compared with CE methods using micelles. Experimental analysis indicated that sulfobutyl ether-β-cyclodextrin associated more strongly with the PAHs than carboxymethyl-β-cyclodextrin.