A sensitive fluorescent probe enables rapid detection of sulfite in food samples within seconds.

Sulfite and its derivatives are commonly used food additives. Excessive intake can severely damage the human respiratory and cardiovascular systems. To ensure food safety, the development of sensitive, convenient, and efficient methods for detecting SO32- and its derivatives is urgently needed. However, existing detection methods suffer from drawbacks such as slow response, poor selectivity, and cumbersome operation. Therefore, this study designed an ICT-modulated fluorescent probe, DEA-PT-Py. By introducing a specific recognition site for SO32-, the probe achieves rapid response (<30 s), high selectivity, and high sensitivity toward SO32- and its derivatives. Upon interaction with SO32-, the probe's fluorescence intensity at 620 nm increases significantly. A good linear relationship between fluorescence intensity and SO32- concentration is observed in the range of 1-4 µmol L-1, and the probe shows no response to common metal-interfering ions. Furthermore, the probe DEA-PT-Py has been successfully applied to the detection of SO32- spiked recovery in tap water and seawater samples, as well as to fluorescence imaging of onion epidermal cells and electrospun fibers. For detecting actual food samples, the probe enables the determination of SO32- and its derivatives in white sugar, rock sugar, and dried beancurd sticks. This work provides a promising analytical tool for the rapid, real-time, and accurate detection of sulfite and its derivatives in environmental and food samples.