Electrokinetic chromatography of twelve monomethylbenz[a]anthracene isomers using a polymerized anionic surfactant

A method for the separation of twelve monomethyl-substituted benz[a]anthrac ene isomers using poly-(sodium undecylenic sulfate) (poly-SUS) surfactant b y means of electrokinetic capillary chromatography (EKC) is described. Seve ral parameters such as concentration of acetonitrile (ACN), pH, as well as applied voltage were studied to optimize the EKC separation. ACN at a conce ntration of 35% v/v, 12.5 mM phosphate-borate buffer, 30 kV with 0.5% w/v p oly-SUS at a pH of 9.5 provided a resolution of a mixture of nine out of tw elve methylbenz[a]anthracene (MBA) isomers in 50 min. The results of this s tudy suggest that molecular length of MBA rather than length-to-breath rati o plays an important role in the elution order of some isomers.