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Direct chiral resolution of tartaric acid by ion‐pair capillary electrophoresis using an aqueous background electrolyte with (1 R ,2 R )‐(–)‐1,2‐diaminocyclohexane as a chiral counterion
Author(s) -
Kodama Shuji,
Yamamoto Atsushi,
Matsunaga Akinobu,
Hayakawa Kazuichi
Publication year - 2003
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.200305440
Subject(s) - tartaric acid , chemistry , phosphoric acid , electrolyte , capillary electrophoresis , aqueous solution , counterion , chiral resolution , enantiomer , chromatography , inorganic chemistry , ion , stereochemistry , organic chemistry , electrode , citric acid
Chiral resolution of native DL ‐tartaric acid was achieved by ion‐pair capillary electrophoresis (CE) using an aqueous‐ethanol background electrolyte with (1 R ,2 R )‐(−)‐1,2‐diaminocyclohexane ( R ‐DACH) as a chiral counterion. Factors affecting chiral resolution and migration time of tartaric acid were studied. By increasing the viscosity of the background electrolyte and the ion‐pair formation, using organic solvents with a lower relative dielectric constant, resulted in a longer migration time. The optimum conditions for both high resolution and short migration time of tartaric acid were found to be a mixture of 65% v/v ethanol and 35% v/v aqueous solution containing 30 m M R ‐DACH and 75 m M phosphoric acid (pH 5.1) with an applied voltage of −30 kV at 25°C, using direct detection at 200 nm. By using this system, the resolution ( Rs ) of racemic tartaric acid was approximately 1. The electrophoretic patterns of tartaric and malic acids suggest that two carboxyl groups and two hydroxyl groups of tartaric acid are associated with the enantioseparation of tartaric acid by the proposed CE method.