Ultra-sensitive fluorescent probes for hypochlorite acid detection and exogenous/endogenous imaging of living cells

Two fluorescent probes (Naph-1 and Naph-2), which can be prepared via a facile process, have been developed to detect hypochlorite acid (HOCl). The N,N-dimethyl thiocarbamate group quenches the fluorescence of the probes through intramolecular charge transfer (ICT). Upon reaction with HOCl in aqueous buffer, Naph-1 shows ultra-high sensitivity towards HOCl through a 4600-fold increase in fluorescence intensity, as well as a detection limit of 2.37 nM. The probes have been applied to confocal fluorescence imaging of exogenous and endogenous HOCl in living cells.