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

• The HMQ probe shows high selectivity and sensitivity for HSO 3 − detection. • A test strip based on HMQ enables rapid SO 2 gas detection for real-time monitoring. • HMQ is versatile, applicable for detection in food, biology, and the environment. Sulfur dioxide (SO 2 ) is a significant atmospheric pollutant and food additive, with excessive sulfite (HSO 3 − ) consumption linked to health risks such as respiratory and cardiovascular disorders. Reliable, sensitive detection of HSO 3 − is essential for food safety and environmental monitoring. Here, we present a novel fluorescent probe (HMQ) for the selective detection of HSO 3 − in biological and environmental samples. The probe exhibits a distinct “ON-OFF” fluorescence response due to a nucleophilic addition mechanism, enabling high selectivity for HSO 3 − over other anions. HMQ was successfully applied for detecting exogenous HSO 3 − 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 HSO 3 − (SO 2 ) 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.