Used primarily as a derivatizing agent in peptide synthesis and amino acid analysis. It introduces the 9-fluorenylmethyloxycarbonyl (Fmoc) protecting group to amines, allowing selective protection of amino functionalities during multi-step syntheses. Its strong UV absorbance and fluorescence enable sensitive detection in HPLC and capillary electrophoresis, especially for trace analysis of primary and secondary amines. Commonly applied in quality control of pharmaceuticals, monitoring of biogenic amines in food, and labeling of biomolecules for analytical detection. Also used in the preparation of fluorescent probes and in solid-phase synthesis due to the stability and ease of removal of the Fmoc group under mild basic conditions.