Effect of cetyltrimethylammonium bromide on the migration of polyaromatic hydrocarbons in capillary electrokinetic chromatography

The separation of different ring numbered polyaromatic hydrocarbons (PAHs) was accomplished by using cetyltrimethylammonium bromide (CTAB) in capillary electrokinetic chromatography. In order to increase the solubilities and selectivities of PAHs, acetonitrile (ACN) was used as an organic modifier. Under the optimised conditions, 11 aromatic compounds were separated within 14.5 min in a running electrolyte containing 10 mM phosphate, 30 mM CTAB, and 40% ACN at pH 6.0. The effects of CTAB and ACN concentrations, voltage and pH on the resolution were investigated. Reproducibilities of migration times range between 0.55 and 1.27 R.S.D.% and peak areas between 1.02 and 7.23 R.S.D.%. Limit of detections (LODs) range between 0.09 and 2.24 μg ml−1. This new and fast separation method of PAHs was applied to cooked oil sample

Capillary electrokinetic separation of polycyclic aromatic hydrocarbons using cetylpyridinium bromide

Polycyclic aromatic hydrocarbons (PAHs) including isomeric pairs were separated in capillary electrokinetic chromatography using a cationic surfactant cetylpyridinium bromide (CPBr) as additive. With addition of 2 mM CPBr into the running electrolyte, dynamic coating occurs in the capillary and EOF is reversed. Changes of electroosmotic and electrophoretic mobilities with increasing CPBr concentration were investigated. Under optimum separation conditions, running electrolyte contains 50% MeCN, 20 mM acetate, and 40 mM CPBr at pH = 4.0. Using high concentration of organic solvent, aggregation of surfactants into micelles is prevented. Significant retentions indicate solvophobic, n- and π-electron interactions between CPBr monomers and PAHs