A method for the determination of the optical purity of a series of chiral aminoacids (AAs) present in brain tissue and brain microdialysates was developed. The method is based on pre-column derivatization of the analytes with the derivatization reagent Nα-(2,4-Dinitro-5-fluorophenyl)-L-alaninamide (Mafrey's reagent).
The derivatization reaction selectively gives diastereomeric amides that are resolvable on a reverse phase UHPLC column. The developed technique covers various aminoacids, which differ significantly in steric and electronic properties.
In all cases, the resolution factors (R) exceeded the value of 1.5. The method represents a robust way of analysis of mixtures of aminoacids, which are often present in various matrixes such as brain tissue and cerebrospinal fluid.