Separation of conjugated linoleic acid isomers by cyclodextrin-modified micellar electrokinetic chromatography

A cyclodextrin-modified micellar electrokinetic chromatography (CD-MEKC) method was developed for separating conjugated linoleic acid (CLA) isomers. All the seven CLA isomers (9cis,11cis-CLA, 9cis,11trans-CLA, 9trans,11trans-CLA, 10trans,12cis-CLA, 11cis,13cis-CLA, 11cis,13trans-CLA and 11trans,13trans-CLA) were completely separated in the optimized conditions (4% (w/v) β-cyclodextrin (β-CD), 54 mM sodium dodecyl sulphate (SDS), 80 mM borate (pH 9.0), 8 M urea, 4% (v/v) ethanol, 30 kV and 15 °C). The CD-MEKC method was superior to the gas chromatographic (GC) and silver-ion high-performance liquid chromatographic (Ag+-HPLC) methods that were generally used in analyzing CLA isomers.