Nitrogen and sulfur co-doped graphene quantum dots for the highly sensitive and selective detection of mercury ion in living cells

A novel nitrogen and sulfur co-doped graphene quantum dots (N,S/GQDs) were synthesized by a simple and green pyrolysis method with citric acid as carbon source, d‑penicillamine as doped molecule. The fluorescence of the obtained N,S/GQDs could be dramatically and selectively quenched by Hg2+ due to the coordination between them. Based on such a recognition effect, a very sensitive and selective fluorescence sensor for the imaging mercury ions in the living cells was developed.154