Separation of polycyclic aromatic hydrocarbon metabolites by γ- cyclodextrin-modified micellar electrokinetic chromatography with laser- induced fluorescence detection

Using a modified micellar buffer consisting of γ-cyclodextrin (γ-CD) and sodium dodecyl sulfate (SDS), we have obtained separations of hydroxy- polycyclic aromatic hydrocarbons (hydroxyPAHs). These compounds are oxidative products of mammalian PAH metabolism. The analytes were detected with a commercial laser-induced fluorescence (LIF) detector. A number of hydroxyPAH isomers could be separated by changes in γ-CD concentration. Baseline resolution of 12 hydroxyPAHs was obtained using 30 mM borate, 60 mM SDS and 40 mM γ-CD. The particular site substitution of the hydroxy group can produce changes in the hydroxyPAH fluorescence spectrum, and the effect of optical filter selection was studied for the LIF detection. The mass detection limits were in the (0.08-0.5)x10^-15 mol range. To our knowledge, this is the first report of the separation of metabolic products of PAHs (and several positional isomers) using γ-CD and micellar electrokinetic chromatography.