Ultrafast fluorescent probe with near-infrared analytical wavelength for fluoride ion detection in real samples

The first ultrafast fluorescence probe with response time in seconds (10 s) for fluoride ions (F−) has been proposed by conjugating dimethylthiophosphoryl group as a recognition unit with the near-infrared fluorophore of hemicyanine. The response mechanism is the F−-induced cleavage of the dimethylthiophosphoryl group, along with the liberation of the fluorophore, which results in a distinctly enhanced fluorescence intensity at 730 nm (λex = 680 nm). The fluorescence enhancement of the probe is directly proportional to the F− concentration in the range of 10–300 µM with the detection limit of 4.28 µM. The probe has been successfully used to determine F− concentration in real water and toothpaste samples as well as image F− in living cells. The simplicity and quick response of this probe endow it with the ability of detecting F− rapidly in real samples.