Development of a selective fluorescent probe for sensitive detection of HSO₃^- in biological and environmental samples

Sulfur dioxide (SO₂) is a significant atmospheric pollutant and food additive, with excessive sulfite (HSO₃^-) consumption linked to health risks such as respiratory and cardiovascular disorders. Reliable, sensitive detection of HSO₃^- is essential for food safety and environmental monitoring. Here, we present a novel fluorescent probe (HMQ) for the selective detection of HSO₃^- in biological and environmental samples. The probe exhibits a distinct "ON-OFF" fluorescence response due to a nucleophilic addition mechanism, enabling high selectivity for HSO₃^- over other anions. HMQ was successfully applied for detecting exogenous HSO₃^- in living cells and for monitoring sulfite contamination in food samples. Additionally, test strips impregnated with HMQ provide a simple and rapid method for detecting HSO₃^- (SO₂) in aqueous solutions and gaseous environments. The probe demonstrates excellent sensitivity, with linear fluorescence responses and high recovery rates in both food and serum samples. This work provides a versatile tool for sulfite detection, with potential applications in food safety, environmental monitoring, and disease research.