Sequential detection of H2S and HClO fluorescence probes and their applications in real sample detection, smartphone sensing development, and bioimaging.

Hydrogen sulfide (H2S) and hypochlorous acid (HClO) are typical environmental pollutants and bioactive substances, and their detection has become increasingly important. A highly effective method for real-time monitoring of H2S and HClO is to utilize a fluorescent probe to detect changes in their levels. In this study, a dual-site chemosensor BPCN-SSPy, based on 2,2'-dithiodipyridine benzoate and dicyanobis(isophorone)ene, was developed for sequential detection of H2S and HClO. The sensor enabled "turn-on" detection of H2S in its fluorescence channel (λem: 611 nm), followed by ratiometric detection of HClO (λem: F520 nm/F611 nm), demonstrating rapid response and high selectivity, and was used for detecting them in real water samples. Notably, the sequential color change response of H2S and HClO using BPCN-SSPy opened up a smartphone sensing platform. BPCN-SSPy demonstrated excellent biocompatibility and can be used for the visualization and imaging of H2S in HeLa cells. Additionally, the solid-state luminescent properties of BPCN-SSPy can make it suitable in potential fingerprint recognition applications.