Hydrogen sulfide detection using nucleophilic substitution-cyclization-based fluorescent probes.

While previously known as a toxic pollutant, hydrogen sulfide (H2S) has been recently classified as an important signaling molecule with potent cytoprotective actions. The study on H2S is a rapidly growing field in biomedical research. Nevertheless, the detection of H2S in biological samples is still a challenge. Fluorescent assays can be very useful in this field owing to their high sensitivity and convenience. Based on the dual nucleophilicity of hydrogen sulfide, a series of reaction-based fluorescence "turn-on" probes have been developed by our lab. In this chapter, we provide an overview of the reactivity/property of these probes and detailed protocols for the use of them in experiments.