A Novel BODIPY-Derived Fluorescent Sensor for Sulfite Monitoring

Sulfur dioxide (SO₂) is commonly employed as an antioxidant and preservative in food processing, but excessive intake of SO₂ can pose significant health risks. Therefore, accurate detection of sulfite content in food is crucial for ensuring food quality and safety. A novel fluorescent probe, BODIPY-Y, composed of a BODIPY derivative and an ethyl cyanoacetate group linked by a carbon-carbon double bond, was synthesized for detecting sulfur dioxide derivatives. When the BODIPY-Y probe interacts with SO₃^2-, the probe exhibits enhanced fluorescence at 514 nm. Spectrometric experiments show that the probe exhibits high sensitivity (<i>LOD</i>: 0.263 μmol/L), a fast response time (50 s) and excellent selectivity for SO₃^2-. Mechanistic studies confirm that the BODIPY-Y probe operates via an intramolecular charge transfer (ICT) mechanism. The carbon-carbon double bond in BODIPY-Y undergoes nucleophilic addition with SO₃^2-, blocking the ICT process and resulting in a blue shift in the fluorescence spectrum. In addition, the probe was applied to quantify SO₃^2- levels in real food samples. The measured concentrations of SO₂ in the white sugar and red wine were 15.93 μmol/L and 7.30 μmol/L, respectively, with recovery rates of 77.9-98.1%. This work presents a prospective chemical tool for monitoring sulfur dioxide derivatives in food products.