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Direct enantioseparation of lipoic acid in dietary supplements by capillary electrophoresis using trimethyl‐β‐cyclodextrin as a chiral selector
Author(s) -
Kodama Shuji,
Taga Atsushi,
Aizawa Senich,
Kemmei Tomoko,
Honda Yoshitaka,
Suzuki Kentaro,
Yamamoto Atsushi
Publication year - 2012
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.201100531
Subject(s) - lipoic acid , capillary electrophoresis , enantiomer , chemistry , cyclodextrin , chromatography , chiral resolution , resolution (logic) , phosphate buffered saline , electrolyte , thioctic acid , antioxidant , organic chemistry , artificial intelligence , computer science , electrode
Lipoic acid, an antioxidant, naturally occurs as the ( R )‐enantiomer, while synthetic lipoic acid is racemic. It is thus of interest to know the ( R )‐enantiomer content of lipoic acid supplements. Here, we used capillary electrophoresis to directly enantioseparate lipoic acid in dietary supplements by using a sulfonated capillary with an effective voltage of +18 kV and direct detection at 200 nm. Factors affecting migration time and resolution of lipoic acid were investigated. The optimum background electrolyte was found to be 100 mM phosphate buffer (p H 7.0) containing 8 mM trimethyl‐β‐cyclodextrin as a chiral selector at 20°C. Under the proposed conditions, direct chiral resolution of lipoic acid in dietary supplements was conducted successfully.