Used as a sulfhydryl-reactive reagent in biochemical and molecular biology research, particularly for modifying cysteine residues in proteins. It helps in studying protein structure and function by selectively attaching alkyl thiol groups, enabling disulfide bond formation or blocking free thiols. Its long dodecyl chain enhances membrane permeability, making it useful in probing membrane proteins or cellular systems where access to hydrophobic regions is required. Also employed in site-directed spin labeling and functional studies of ion channels and receptors.