Used as a derivatization reagent in analytical chemistry, particularly in the detection and quantification of thiols and sulfhydryl-containing compounds. Its high reactivity with thiol groups allows for the formation of stable fluorescent or UV-active derivatives, making it valuable in HPLC and LC-MS analyses. Commonly applied in pharmaceutical and biochemical research for monitoring drug metabolites, peptides, and proteins that contain cysteine residues. The acetonitrile solution format ensures good solubility and reactivity, facilitating its use in automated sample preparation workflows.