The micellar liquid chromatographic (MLC) separations of polycyclic aromatic hydrocarbons (PAHs) were optimized for three micellar systems, cetyltrimethylammonium chloride (CTAC), dodecyltrimethylammonium chloride (DTAC), and sodium dodecylsulfate (SDS), with 1-pentanol as the only organic additive. A difference in the separation was observed between CTAC and SDS/DTAC. Under each optimized separation conditions, CTAC-modified mobile phase provides the least desirable separation, which is attributed to its longer carbon tail (C16 vs. C12). In addition to 1-pentanol, the main organic additive, a second organic additive (3% 1-propanol) in the micelle-modified mobile phase was found to enhance the resolution of PAH chromatographic peaks. However, the extent of the enhancement varies for the different micellar systems, with the greatest resolution improvement seen for CTAC, and little effect for shorter-tail SDS and DTAC. This study shows the potential use of second organic additive (1-propanol), to the main nonpolar additive (1-pentanol), in facilitating the MLC separation of larger nonpolar compounds.

Micellar liquid chromatography of polycyclic aromatic hydrocarbons: Alkylpyridinium chloride as mobile phase modifier and selective fluorescence quencherThe dual role of alkylpyridinium chlorides, cetylpyridinium chloride (CPC) and dodecylpyridinium chloride (DDPC), as micellar mobile phase modifiers and selective fluorescence quenching agents of polycyclic aromatic hydrocarbons (PAHs), in micellar liquid chromatographic separation of PAHs is reported. The replacement of 0.037 M cetyltrimethylammonium chloride in the aqueous mobile phase with CPC/DDPC quencher greatly simplifies the observed fluorescence-detected chromatograms, facilitating PAH identification. The resulting chromatograms are similar to those obtained from the conventional approach -pyridinium chloride quencher in an acetonitrile mobile phase. To quantify the quenching, the (F 0 /F -1) values from the Stern-Volmer equation are calculated from the chromatograms and compared. The feasibility of using CPC or DDPC as a dual reagent under isocratic and gradient conditions is shown.