Optimization of micellar liquid chromatographic separation of polycyclic aromatic hydrocarbons with the addition of second organic additive

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 dodecyl-sulfate (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 (C-16 VS. C-12). 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 SIDS 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.