A selenium-based fluorescent sensor for the reversible detection of ClO^- and H₂S in foods

HClO/ClO^- and H₂S are two kinds of momentous biological small molecules in the organism, and the redox balance between them is considerable for the physiological and pathological properties of organisms. Hence, it is very crucial to monitor the redox course between HClO and H₂S. Herein, a reversible fluorescent sensor (IPSe) for ClO^- and H₂S was firstly constructed with the selenium atom as the response site and the dicyanoisophorone as the fluorophore. The sensor IPSe could detect ClO^- with good selectivity and sensitivity due to the oxidation reaction of the selenium atom triggered by ClO^-. The recognition of IPSe to hypochlorite induced a hypsochromic shift of the absorption maximum from 420 nm to 380 nm. IPSe exhibited the prominent low detection limit of 55.3 nM for detecting ClO^-, accompanied by distinct fluorescent attenuation. Moreover, H₂S could efficiently return the fluorescence of the IPSe solution to the original level by H₂S reducing selenoxide. The experimental results show that the suggested method has high precision and accuracy for the detection of ClO^- and H₂S. The applications in real water samples, beverages and cell imaging verified that the IPSe was capable of monitoring the changes in the concentration of ClO^-/H₂S, which indicates that it is of great meaning to survey the biological functions of ClO^- and H₂S via IPSe.