A benzothiazole-based ratiometric fluorescent probe with large Stokes shifts for quantitative profiling of sulfite in real samples and living cells

Rapid, selective, and quantitative profiling of SO32-is a prerequisite for investigating its effect on different physiopathological processes. To address this challenge, our team prepared a ratiometric fluorescent probe HBTC-S, based on 4-(benzothiazol-2-yl)-3-hydroxybenzaldehyde for specific detection of SO32-under a single-wavelength excitation. The solution of probe HBTC-S itself exhibited orange fluorescence (.Iem = 614 nm), and became green fluorescent (.Iem = 471 nm) after the addition of SO32-. The vitro experiments suggested that the probe displayed high sensitivity, excellent selectivity, and a low detection limit (0.15 mu M). Moreover, probe HBTC-S was successfully applied for qualitative and quantitative monitoring of SO32-in realistic samples and living HeLa cells in a ratiometric manner.