Premium
A comparison of ionic liquids to molecular organic solvents as additives for chiral separations in micellar electrokinetic chromatography
Author(s) -
Mwongela Simon M.,
Siminialayi Noreen,
Fletcher Kristin A.,
Warner Isiah M.
Publication year - 2007
Publication title -
journal of separation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.72
H-Index - 102
eISSN - 1615-9314
pISSN - 1615-9306
DOI - 10.1002/jssc.200600455
Subject(s) - micellar electrokinetic chromatography , micelle , ionic liquid , chemistry , alkyl , electrolyte , tetrafluoroborate , aqueous solution , selectivity , electrokinetic phenomena , analyte , chromatography , analytical chemistry (journal) , capillary electrophoresis , organic chemistry , electrode , catalysis
In this study, we report the effects of adding ionic liquids (ILs), as compared to adding conventional molecular organic solvents (MOSs), to aqueous buffer solutions containing molecular micelles in the separation of chiral analyte mixtures in micellar EKC (MEKC). The molecular micelle used in this study was polysodium oleyl‐ L ‐leucylvalinate (poly‐ L ‐SOLV). The ILs were 1‐alkyl‐3‐methylimidazolium tetrafluoroborate, where the alkyl group was ethyl, butyl, hexyl, or octyl. These ILs were chosen due to their hydrophobicity, good solvating, and electrolyte properties. Thus, it was expected that these ILs would have favorable interactions with chiral analytes and not adversely affect the background current. Common CE buffers, mixed with a molecular micelle, and an IL or a MOS, were used for these chiral separations. The buffers containing an IL in the concentration range of 0.02–0.1 v/v were found to support a reasonable current when an electric field strength of 500 V/cm was applied across the capillary. However, a current break down was observed for the buffers containing more than 60% v/v MOS on application of the above‐mentioned electric field. The chiral resolution and selectivity of the analytes were dependent on the concentration and type of IL or MOS used.