A ratiometric fluorescent probe based on phenothiazine and HBI motif for rapid detection of HClO and its applications

A deep-red emissive fluorescence probe PT-HBI with phenothiazine and 4-(4-hydroxybenzylidene)-1,2-dimethyl-1H-imidazole-5(4H)-one (HBI) motif was designed and synthesized for rapid detection of HClO in a fine ratiometric manner. PT-HBI exhibited remarkable ratiometric fluorescence response to HClO within 50 s, achieving a large Stokes shift (120 nm), high sensitivity (LOD = 0.31 μM) and excellent selectivity. Among the tested analytes, only addition HClO to PT-HBI enables result from a significant fluorescence change from red emission (λmax = 660 nm) to yellow emission (λmax = 540 nm) with the ratio of F540/F660 displaying a 175-fold enhancement. In particular, PT-HBI was capable of monitoring exogenous HClO in Hela cells by ratiometric fluorescence imaging. Moreover, the probe PT-HBI has provided an extensive application for detection of HClO in real water samples and on paper-based sensor to detect HClO in different concentration.