Dansyl Ethylenediamine, 5-Dimethylaminonaphthalene-1-(N-(2-Aminoethyl))sulfonamide

The primary aliphatic amine of dansyl ethylenediamine can be reversibly coupled to aldehydes and ketones to form a Schiff base - which can be reduced to a generate stable amine derivative by sodium borohydride (NaBH₄) or sodium cyanoborohydride (NaCNH₃). Carboxylic acids of proteins and other water-soluble biopolymers can be coupled to this molecule in aqueous solution using water-soluble carbodiimides such as EDAC (E2247). This fluorophore is lipophilic and environmentally-sensitive.