CE-LIF chiral separation of aspartic acid and glutamic acid enantiomers using human serum albumin and sodium cholate as dual selectors

Sodium cholate (SC), β-CD, hydroxypropyl (HP)-β-CD, HSA, and the dual mixtures of them were evaluated for the analysis of aspartic acid (Asp) and glutamic acid (Glu) enantiomers fluorescently tagged with 5-(4,6-dichloro-s-triazin-2-ylamino) fluorescein (DTAF) by CE with LIF detection. Among the investigated chiral selectors and the dual selector systems, the dual selector systems of HSA and SC resulted to be the most useful chiral selectors allowing relatively high chiral resolution. Several experimental parameters such as chiral reagent type and concentration, buffer concentration, and pH, type and concentration of organic modifier were studied in order to find the optimum conditions for the chiral resolution of the two derivatized amino acids in their enantiomers. The effect of different variables that affect derivatization (time, temperature, pH, and DTAF concentration) was studied. Under optimum conditions, the analytes were separated in a short 10.5 min analysis time, and the RSDs for migration time and peak area were less than 0.12 and 2.8%, respectively. The method was applied for the analysis of compound amino acids injection without interference from other amino acids in the sample matrices observed.