A novel fluorescent probe for sensitive detection and imaging of hydrazine in living cells

A turn-on fluorescent probe (Naphsulf-O) for hydrazine was developed by protecting the hydroxy group of the fluorophore 6-acetyl-2-hydroxynaphthalene via O-4-nitrobenzenesulfonylation, where 4-nitrobenzene was used as a fluorescence quenching moiety as well as an electrophile. Upon nucleophilic aromatic substitution (NAS) reaction of hydrazine toward the probe, the protecting group was removed and fluorophore was released. The probe exhibits a large Stokes shift, excellent selectivity and high sensitivity for hydrazine detection in aqueous solution with a detection limit of 0.716 ppb (22 nM), which is of great importance in both environmental and biological system. Furthermore, it was successfully applied to imaging of hydrazine in living cells.