A colorimetric and ratiometric fluorescent probe for rapid, sensitive and visual detection of metabisulfite in food and living cells

Sodium metabisulfite (Na2S2O5) is widely used as a bleaching agent and food preservative. However, excess of S2O52- can irritate and damage the human body. In this study, we report a colorimetric and ratiometric fluorescent probe for visual detection of S2O52-. The probe can quantitatively determine S2O52- with high specificity and sensitivity, fast response (<30 s) as well as a low detection limit (6.8 nM). A 1,4-Michael addition reaction was proposed for the sensing mechanism of this probe, which was confirmed by H-1 NMR and HR-MS spectra. The probe has been successfully utilized to determine S2O52- in food with good recovery, from the remarkable colorimetric and ratiometric fluorescence changes. The probe was also employed to visualize S2O52- in live cells. Furthermore, the probe has been successfully prepared into a portable kit for real-time visual detection of S2O52- in food. Therefore, this probe has great potential application for the detection of S2O52- in food and living cells.