Separation of various positional isomers of aromatic anions by nonionic micellar electrokinetic chromatography coupled with ion association distribution

Separation of positional isomers of aromatic anions was studied by micellar electrokinetic chromatography using nonionic surfactants and/or an ion ass ociation reagent. The isomers were well resolved by adding nonionic surfact ant in the migrating solution, which indicates that binding of the anions t o a nonionic surfactant micelle is different among the isomers. The apparen t electrophoretic mobility of the anions decreased with increasing concentr ations of the surfactants in the migrating solution, and the binding phenom ena are analyzed from the electrophoretic mobility change. Addition of an i on association reagent in the migrating solution also changed the resolutio ns. Some binding constants of the ion associates are also determined throug h the mobility change. (C) 2000 John Wiley & Sons, Inc.