Enantioselectivity of structurally modified poly(sodium undecenoyl-L-leucinate) by insertion of Triton X-102 surfactant molecules

The effectiveness of Triton X-102 (TX-102), as a structural modifier of the polymeric surfactant sodium undecanoyl-L-leucinate (L-SUL) was investigated for enhanced enantiomeric recognition of various chiral compounds in micellar electrokinetic chromatography (MEKC). Increasing concentrations of TX-102 were separately added into the micellar solutions Of L-SUL and then polymerized to form poly-L-SUL. The resulting polymers were purified by use of 3500 molecular-weight-cutoff (MWCO) dialysis membranes. Fluorescence and pulsed field gradient-nuclear magnetic resonance (PFG-NMR) techniques were used to elucidate the structural effects of TX-102 on poly-L-SUL. Evaluation of data from fluorescence measurements suggested an increase in polarity with increasing concentration of TX-102. However, the polarity decreased at higher concentrations of TX-102. Evaluation of data from PFG-NMR suggested an increase in hydrodynamic radius upon increasing the concentration of TX-102. The racemates of coumarinic and phenythiohydantoin amino acid derivatives, and pindolol were used as test analytes in MEKC. A notable increase in resolution and capacity factors of the test analytes was observed when the modified poly-L-SUL was used in MEKC measurements. Examination of the data obtained from fluorescence, PFG-NMR, and MEKC suggests a strong correlation between the polarity and the hydrodynamic radii of TX-102 modified micelles and the enantiomeric resolution of the test analytes. © 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim