Bifunctional near-infrared fluorescent probe for the selective detection of bisulfite and hypochlorous acid in food, water samples and in vivo.

We report the development of a bifunctional near-infrared fluorescent probe (QZB) for selective sensing of bisulfite (HSO) and hypochlorous acid (HOCl). The synergistic detection of HSO and HOCl was achieved via a C=C bond recognition site. In comparison with the red-fluorescence QZB, two different products with non-fluorescence and paleturquoise fluorescence were produced by the recognition of QZB towards HSO and HOCl respectively, which can realize effectively the dual-functional detection of HSO and HOCl. QZB features prominent preponderances of dual-function response, near-infrared emission, reliability at physiological pH, low cytotoxicity and high sensitivity to HSO and HOCl. The detection of HSO in actual food samples has been successfully achieved using QZB. Utilization of QZB-based test strip to semi-quantitatively detect HSO and HOCl in real-world water samples by the "naked-eye" colorimetry are then demonstrated. Simultaneously, the determination of HSO and HOCl in real-world water sample has been achieved by smartphone-based standard curves. Additionally, the applications of QZB for imaging HSO and HOCl in vivo are successfully demonstrated. Consequently, the successful development of QZB could be promising as an efficient tool for researching the role of HSO/HOCl in the regulation of redox homeostasis regulation in vivo and complex signal transduction and for future food safety evaluation.