Determination of aspartic acid enantiomers in bio-samples by capillary electrophoresis

Enantiomeric separation and detection of D,L-aspartic acid (Asp) derivatized with 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F) by capillary electrophoresis (CE) using modified cyclodextrins as chiral selectors was studied. Heptakis(2,3, 6-tri-O-methyl)-beta-cyclodextrin(TM-beta-CD) was most effective for enantiomeric separation of NBD-D,L-Asp with optimum conditions of 30 mM TM-beta-CD in 50 mM phosphate buffer (pH 4.0) and the limit of detection (LOD) attained was 100 nM for each enantiomer. The method proposed in the present study was convenient for both D- and L-Asp determination since the other amino compounds migrated differently and D-Asp in bio-samples such as rat pineal gland and foods was determined with a simple sample pretreatment and a short analysis run time.