Characterization of chemical selectivity in micellar electrokinetic chromatography: V. The effect of the surfactant hydrophobic chain

The influence of the surfactant hydrophobic chain on selectivity in micellar electrokinetic chromatography was investigated using two sets of surfactants. A series of three sarcosinate surfactants (sodium N-lauroyl sarcosinate, sodium n−myristoyl sarcosinate, and sodium N-parmitoyl sarcosinate) with C11, C13, and C15 hydrocarbon tails were compared. In addition, sodium dodecyl sulfate and sodium tetradecyl sulfate were investigated to determine the chain length effect for sodium sulfate surfactants. Linear solvation energy relationships as well as free energy of transfer studies were used to predict the selectivity differences. The results suggest that although the surfactant chain length can have some effect, the magnitude of this influence seems to be dependent on the head group. © 2000 John Wiley & Sons, Inc. J Micro Sep 12: 433–441, 2000