A New Red-Emitting Fluorescence Probe for Rapid and Effective Visualization of Bisulfite in Food Samples and Live Animals

The development of new methods for rapid and effective detection of bisulfite (HSO3–) in food samples and imaging of HSO3– intake in animals is of significant importance due to the key roles of HSO3– in food quality assurance and community health. In this work, a new responsive fluorescence probe, EQC, is reported for the quantitative detection of HSO3– in food samples and visualization of HSO3– intake in animals. Upon addition of HSO3–, the UV–vis absorption and red emission of EQC were significantly decreased within 120 s. The changes in absorption and emission spectra of EQC were rationalized by theoretical computations. The proposed reaction mechanism of EQC with HSO3– was confirmed by high-resolution mass spectrometry (HRMS) and spectroscopic titration measurements. EQC has the advantages of high sensitivity, selectivity (a detection limit of 18.1 nM), and fast response toward HSO3–, which enable rapid and effective HSO3– detection in buffer solution. The practical applications of EQC were demonstrated by the detection of HSO3– in food samples and the imaging of HSO3– intake in live animals.