Used as a fluorescent labeling reagent for thiols in biochemical and analytical applications. Its high sensitivity and selectivity toward thiol groups make it suitable for detecting and quantifying low levels of biological thiols such as cysteine, glutathione, and proteins with free cysteine residues. Commonly applied in HPLC and capillary electrophoresis for derivatization of thiol-containing compounds, enhancing detection limits due to strong fluorescence emission. Also employed in studies of oxidative stress and redox biology where monitoring thiol status in cells is critical. The presence of both acetamido and mercapto groups allows for selective reactions and improved stability of the labeled products.