N-Hydroxysulfosuccinimide Sodium Salt is a variant of N-Hydroxysuccinimide (NHS, ), derivatized with a sulfate group to confer hydrophilicity. N-Hydroxysulfosuccinimide Sodium Salt can be utilized similarly to NHS to activate carboxylic acids of interest to the more reactive succinimidyl esters for coupling, biotinylation, and conjugation with fluorophores. Also used for crosslinking agents.