Facile access to a methylthiocoumarinyl formate as highly selective and sensitive fluorescent probe for hypochlorite

Development of effective methods for analyzing hypochlorite is of great significance due to the crucial role of hypochlorite in live organisms, as an endogenously produced reactive oxygen species (ROS) in the human immune system. In this paper, a novel fluorescent probe based on 6-methylthiocoumarinyl formate was designed and synthesized in one step for detection of hypochlorite in MeCN/PBS (8:2, v/v, pH 7.4) medium. The probe showed high specificity for hypochlorite over other competitive ROS analytes, extreme large Stokes shift of 265 nm, rapid response to hypochlorite within 20 s, low detection limit of 1.57 μM, and a wide applicable range of pH 3–10. The sensing mechanism was demonstrated to be based on oxidation of methyl phenyl sulfide to sulfoxide by hypochlorite. The probe may have extensive application for selective and convenient detection of hypochlorite due to its multiple advantages.