A ratiometric fluorescent probe for detection of endogenous and exogenous hydrogen sulfide in living cells.

A ratiometric visualized fluorescent probe of HS of intramolecular charge transfer (ICT) and excited intramolecular proton transfer (ESIPT) mechanisms due to solvation effects has been designed and synthesized. This chemosensor shows the distinct signal changes with dual-emission in blue and green fluorescence spectral channel (from 495 nm to 525 nm) upon the addition of HS in a single wavelength excitation. This chemosensor exhibits the low detection limit (91 nM) and high sensitivity and selectivity. Based on this, this chemosensor was successfully used not only to monitor HS exogenously but also used to detect and image the endogenously generated HS in HeLa cells with excellent performance.