Separation of polycyclic aromatic hydrocarbons by using micellar electrokinetic chromatography

In this work, the use of micellar electrokinetic chromatography (MEKC) for the separation of five polycyclic aromatic hydrocarbon (PAH) compounds is investigated. All of the compounds studied are listed by the United States Environmental Protection Agency as priority pollutants. In micellar electrokinetic chromatography, solutes partition between the aqueous phase and the micellar phase. This partition is based on the hydrophobicity of each compound. In some cases, organic modifiers are added to the electrophoretic solution to enhance the separation efficiency. The organic modifier used in this study is y-cyclodextrin (y-CD), and sodium dodecyl sulfate (SDS) is used as the micellar phase. When both y-CD and SDS are in the electrophoretic solution, a water insoluble, hydrophobic solute is partitioned between the micelles and the y-CD cavity. When the solute is included in the y-CD cavity, which is neutral, it migrates toward the cathode with the electroosmotic velocity. When a solute is incorporated into the SDS micelle, it migrates with the micellar velocity. This differential partition of the solute between the y-CD cavity and the SDS micelles enables the separation to be achieved. The Hewlett Packard HP3DCE system was used to perform the separation. Satisfactory separation was achieved by using an electrophoretic solution comprised of phosphate-borate buffer of pH 7.0 with 10 millimoles of SDS and 2 millimoles of y-CD, in a 50 gm x 56 cm capillary at 15 kilovolts