Used as a fluorescent labeling reagent for chiral amino group detection in analytical chemistry. Its high selectivity for primary amines allows sensitive detection of enantiomeric impurities in pharmaceutical intermediates. Commonly applied in HPLC and capillary electrophoresis to resolve and quantify trace amounts of (R)- and (S)-amino acid derivatives due to its stereospecific reactivity. Also employed in bioconjugation for labeling peptides and proteins where chirality at the proline moiety influences binding affinity. The nitrobenzoxadiazole group provides strong fluorescence with high quantum yield, enabling detection at low concentrations in biological and environmental samples.