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

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 (λ_em: 611 nm), followed by ratiometric detection of HClO (λ_em: F_{520 nm}/F_{611 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.