A Reaction‐Based Fluorescent Probe for Imaging of Native Hypochlorous Acid

Abstract Hypochlorous acid (HOCl), one of the reactive oxygen species (ROS), is highly reactive and short‐lived. It is a challenge to dynamic monitor HOCl activity in living systems. Hence, we synthesized a new fluoresce nt probe RF1 based on protection of the hydroxyl group by N , N ‐dimethylthiocarbamate recognition group, which reached a low fluorescence background signal and highly sensitive property. On account of the electrophilic addition of Cl + to the sulfide of thiocarbamate moiety, probe RF1 was converted to resorufin and triggered emitting bright. RF1 showed not only the highly sensitive and selective response to HOCl in vitro, but also can be applied in environmental water samples and detected HOCl by test strips. Besides, the ability of RF1 monitoring HOCl in HeLa cells by exogenous simulation and tracing native HOCl in macrophages cells were also explored.