A colorimetric and ratiometric fluorescent probe for metabisulfite detection and its application in food safety...

Metabisulfite (S₂O₅^2-) plays a critical role in the chemical, pharmaceutical, and food industries. However, excessive residues or prolonged exposure to S₂O₅^2- can pose significant risks to human health. To enable rapid, effective, and convenient detection of its content, a colorimetric and ratiometric fluorescent probe (CQ1) based on the coumarin-quinoline scaffold has been developed. This probe allows for the highly selective detection of S₂O₅^2- through characteristic fluorescence ratio variations (F₄₈₅/F₇₀₆), with a low limit of detection (LOD) of 1.68 μM, relative standard deviations (RSD) ranging from 1.05 % to 2.67 %, and recovery rates between 91.6 % and 102.57 %. The probe has been successfully utilized in diverse practical applications, including portable test strips, and wearable gloves for dynamic monitoring of S₂O₅^2- residues on vegetable surfaces, as well as direct ratiometric and colorimetric detection of S₂O₅^2- in preserved fruits and nuts. These findings demonstrate that the probe offers a promising method for the monitoring and analysis of S₂O₅^2- in the field of food safety.