A 4‐Methylumbelliferone‐based Fluorescent Probe for Sodium New Houttuyfonate

Abstract A new fluorogenic probe for sodium new houttuyfonate (SNH) was proposed. 4‐Methylumbelliferyl‐2,4‐dinitrobenzenesulfonate (4‐MUDNBS) was a nonfluorescent compound and was synthesized via the one‐step reaction of 4‐methylumbelliferone (4‐MU) with 2,4‐dinitrobenzenesulfonyl chloride. In basic media, SNH was decomposed to produce sodium sulfite, which then reacted with 4‐MUDNBS to yield highly fluorescent 4‐MU, hence leading to the fluorescence increase of the reaction solution. A linear correlation existed between the emission intensity and the concentration of SNH within the range from 0.5 to 15 μg·mL −1 with a detection limit of 0.15 μg· mL −1 (3 δ ). The effect of substituents on the benzenesulfonyl moiety of the probe is discussed, and the presence of electronegative groups is favorable for the proposed cleavage reaction.