A novel ratiometric and colorimetric fluorescent probe for hypochlorite based on cyanobiphenyl and its applications

Reported here is a novel ratiometric and colorimetric fluorescent probe 1 for hypochlorite based on cyanobiphenyl and diaminomaleonitrile. This probe 1 was designed based on the mechanism that ClO− selectively cleaved the hydrazone bond (-C=N-) in this probe and released the fluorophore, 3`-formyl-4`-hydroxy-4-biphenylcarbonitrile. The addition of ClO− to the solution of probe 1 resulted in a very large blue-shift in both fluorescence (107 nm) spectra and an obvious fluorescence color change from red to green. Furthermore, this probe displays a rapid response (30 s) and a low detection limit (3.34 × 10−7 M, based on LOD = 3σ/slope) in detecting ClO−. Importantly, practical utility of this probe for the selective detection of ClO− in living cells has been successfully demonstrated, illustrating the great potential for biological analysis. Additionally, the probe 1 was also successfully applied to the detection of ClO− in real water sample.