Effect of the polar groups of anionic surfactant on migration behavior in micellar electrokinetic chromatography

Abstract

Three kinds of anionic surfactants with different polar groups were used as the pseudo-stationary phase in micellar electrokinetic chromatography (MEKC). We found that sodium N-lauroyl-N-methyl-β-alaninate (ALE) can be used as a pseudo-stationary phase in MEKC, as well as sodium N-lauroyl-N-methyltaurate (LMT) and sodium dodecyl sulfate (SDS). The ionic groups are carboxylate, sulfonate and sulfate, respectively. ALE and LMT have amido linkages. The migration behavior of aniline derivatives and phenol derivatives was investigated with these surfactants. The difference in the migration behavior was compared in terms of the capacity factor. Surfactants with amido linkages showed different selectivity from SDS, for phenol derivatives. The three surfactants also gave different selectivity for aniline derivatives. Changing the buffer pH affected greater the migration behavior of aniline derivatives with SDS than those with ALE and LMT. The correlation of the capacity factor and the octanol-water partition coefficient for each solute was also investigated. Correlation with ALE was the highest among the three surfactants.