Development of an Ultrafast Quinolinium‐Based Fluorescent Probe for Sulfite Detection in Food and Water Samples and Imaging of SO ₂ Derivatives in HeLa Cells

Sulfur dioxide (SO 2 ), as a key atmospheric pollutant, has significant environmental implications due to its transformation in the atmosphere. Sodium sulfite (Na 2 SO 3 ) as one major derivative of SO 2 , are traditionally used as a preservative agent However, excessive intake and exposure to sulfur dioxide may a harmful to human health. Herein, we designed and synthesized a novel fluorescent probe SO2TY1 for detecting SO 3 2 − in environment, food, and bioimaging. Based on sulfur dioxide and its derivatives exhibit remarkable affinity, the design idea of the probe is a novel ICT characteristics model, which 1‐methylquinolinium acceptor group was introduced into the skeleton of chalcone derivative to formed an A‐π‐A system, SO 3 2 − triggered the structural transformation from an A‐π‐A to a D‐π‐A configuration. This process activated the prominent ICT effect, resulting in a longer wavelength fluorescence emission. Probe SO2TY1 showed good sensing performance against SO 3 2 − , including turn‐on fluorescence emission, ultra‐rapid response (<5 s), low detection limit (1.85 nM) in a linear detection range of 0–20 µM, high sensitivity, strong resistance to interference, and a wide pH range (7–11) of applicability. More importantly, probe SO2TY1 has been favorably utilized for detecting sulfite in food, water samples, and bioimaging.