A BODIPY-based reactive probe for ratiometric fluorescence sensing of mercury ions

A simple BODIPY derivative is demonstrated to fluorescently sense Hg2+ in a ratiometric manner. The probe, an 8-methylthio-BODIPY, undergoes Hg2+-promoted hydrolysis to produce the corresponding 8-hydroxy-BODIPY, which conversion is accompanied with a large emission wavelength change. The probe can selectively detect Hg2+ over various other metal cations, with a detection limit of 1 ppb.