Smartphone-assisted fluorescent probe based on quinoline salts for detecting bisulfite and its application in cells and zebrafish imaging

Accurate monitoring of bisulfite (HSO 3 − ) in biological and complex matrices is crucial for elucidating its physiological and pathological roles. Here, a turn-on fluorescent probe QA was developed based on a quinoline platform. Upon reaction with HSO 3 − via a specific nucleophilic addition reaction, QA exhibits high selectivity for HSO 3 − and remarkable turn-on fluorescence response at 628 nm, with high sensitivity (LOD=0.263 μM) and good linear response ranging from 2 to 15 μM. Moreover, a portable platform was constructed by integrating QA into test strip for rapid on-site detection using a smartphone-based system under UV light. In addition, QA can effectively monitor HSO 3 − in diverse food samples (liquor, beer, wine, rock sugar, and canned fruits), achieving spike recovery rates of 89.60% to 105.80%. Furthermore, QA was successfully applied for the fluorescence imaging of exogenous HSO 3 − in live HeLa cells and zebrafish, confirming its good cell permeability and biocompatibility. These findings establish QA as a reliable tool for HSO 3 − detection in both food safety and bioimaging applications. • QA was designed for detecting HSO 3 ⁻ with excellent selectivity and high sensitivity. • QA has been successfully applied for the detection of HSO 3 ⁻ in food samples. • QA has been successfully applied for imaging HSO 3 ⁻ in both cells and zebrafish.