A distinctive near-infrared fluorescence turn-on probe for rapid, sensitive and chromogenic detection of sulfite in food

Sodium sulfite (Na 2 SO 3 ) is widely used as a food additive , but the excessive residue of SO 3 2− in food can cause irritative effects and damages to the human body. In this study, we reported a novel near-infrared (NIR) fluorescent probe ( DCMQ ) for visual detection of SO 3 2− based on a chromogenic reaction. The probe can quantitatively determine SO 3 2− with high specificity and sensitivity, fast response (<50 s) as well as a low detection limit (31.6 nM). A 1,4-Michael addition reaction was proposed for the sensing mechanism of this probe, which was confirmed by 1 H NMR and HR-MS spectra. The probe has been successfully utilized to determine SO 3 2− in food with good recovery, remarkable chromogenic effect and NIR fluorescence turn-on response. Furthermore, the probe has been prepared as a reagent kit for instant on-site visual detection of SO 3 2− in food. Therefore, this probe has great potential application for the detection of SO 3 2− in food.