Perylene dye-functionalized silver nanoparticles serving as pH-dependent metal sensor systems

Lysine-functionalized perylene was used to modify nanoparticles. Due to the benefits from a synergetic effect that originated between the perylene and silver nanoparticles, color-based metal sensor systems were established. At pH = 12.6, Cr6+ with a concentration of 100 nM could be detected by a color change from deep yellow to orange; after decreasing the pH to 12.0, the detection limit decreased to 2 mu M. Interestingly, after further decreasing the pH to 11.0, another kind of metal ion (Cd2+) could be recognized with a detection concentration of 10 mu M. At pH = 10.0, Pb2+ with a concentration of 2 mu M could be detected.