A versatile aggregation-induced emission probe: Accurate quantification, on-site detection, and bioimaging of sulfur...

Sulfur dioxide (SO₂), converted to SO₂ derivatives (SO₃^2-/HSO₃^-) in aquatic environments, is a double-edged molecule that plays an important role in food and biological systems. However, developing rapid, highly sensitive, and versatile fluorescent probes for in situ detection of SO₂ derivatives remains a significant challenge. Herein, we developed a novel aggregation-induced emission (AIE) fluorescent probe, TPE-YD, for specific detection of SO₂ derivatives based on an intramolecular charge transfer (ICT) mechanism. TPE-YD exhibited a distinct AIE effect and strong near-infrared (NIR) fluorescence at 710 nm in solution. Upon reaction with SO₂ derivatives, the UV-Vis absorbance at 450 nm and the fluorescence intensity at 710 nm decreased significantly as SO₂ derivatives increased, with a large Stokes shift (260 nm). The fluorescence intensity showed a strong linear correlation with SO₂ derivatives (R² = 0.994). This method demonstrated high sensitivity, with a limit of detection (LOD) of 61 nM, enabling accurate detection of SO₂ derivatives in both food samples and cells. In addition, TPE-YD enabled convenient (one-step, on-the-spot) measurement of SO₂ derivatives (LOD: 57 nM) in real samples using a smartphone-based colorimetric method. This study provided a new strategy to detect SO₂ derivatives in real samples and organisms accurately.