Dansyl-based fluorescent sensor for highly sensitive detection of nitroaromatics in solution

Fluorophores, (S)-5-(dimethylamino)-N-(1-phenylethyl)naphthalene-1-sulfonamide (DNS-S-PEA) and N-(2-(1H-indol-3-yl)ethyl)-5-(dimethylamino)naphthalene-1-sulfonamide (DNS-TRY), were synthesized by sulfonamide group formation applying dansyl and amine interaction in a single step in an aqueous medium, and their photophysical properties and interactions with various nitroaromatics were investigated. DNS-S-PEA and DNS-TRY showed emission at 522 nm and 520 nm, respectively, with excitation at 341 nm showing large stokes shifts. The fluorophores exhibited a linear fluorescence quenching response toward increasing concentrations of nitroaromatics. Surprisingly, the dynamic quenching constant (K sv ) was significantly higher for metronidazole compared with the other four quenchers. These fluorophores demonstrated high potential for the sensitive and selective detection of metronidazole in solutions and in real samples.