A highly selective fluorescent probe for fast detection of hydrogen sulfide in aqueous solution and living cells.

A new ratiometric fluorescence probe E1 based on an excited-state intramolecular proton transfer (ESIPT) mechanism for detection of hydrogen sulfide (H(2)S) is reported. E1 responds to H(2)S quickly and showed a 30-fold fluorescence enhancement in 2 minutes. Moreover, E1 can detect H(2)S quantitatively with a detection limit as low as 0.12 μM in aqueous solution. Its potential for biological applications was confirmed by employing it for fluorescence imaging of H(2)S in living cells.