A near-infrared fluorescent probe for imaging of bisulfite in living animals and its application in food samples

Bisulfite (HSO3 ) has been widely used as an antioxidant, enzyme inhibitor and antimicrobial agent in foodstuffs, pharmaceutical and beverages industries. It is also a signaling molecular in the cardiovascular and cerebrovascular systems. Nevertheless, a high level of HSO3 can cause allergic reactions and asthmatic attacks. Accordingly, the monitoring of HSO3 levels possesses momentous significance from the perspectives of biological technology and food security supervision. Herein, a near-infrared fluorescent probe LJ is rationally constructed for sensing HSO3 . The fluorescence quenching recognition mechanism was realized by the addition reaction of electron-deficient C--C bond in probe LJ and HSO3 . Probe LJ revealed multifarious preponderances such as longer wavelength emission (710 nm), low cytotoxicity, larger Stokes shift (215 nm), better selectivity, higher sensitivity (72 nM) and short response time (50 s). Encouragingly, probe LJ can detect HSO3 in living zebrafish and mice in vivo by fluorescence imaging techniques. In the meantime, probe LJ was also successfully employed to semi-quantitatively detect HSO3 in real foodstuff samples and water samples by the "naked-eye" colorimetry without the help of any special instruments. More importantly, quantitative detection of HSO3 in practical food samples was achieved through a smartphone application software. Consequently, probe LJ is expected to provide an effective and convenient way for the detection and monitoring of HSO3 in organisms and for food safety detection, which has tremendous application potential.