Silver Nanoparticle Modified Graphene Paste Electrode for the Electrochemical Detection of Lead, Cadmium and Copper

Silver nanoparticle (AgNP) graphene paste electrodes were fabricated from graphene powder mixed with mineral oil and silver nanoparticles. Anodic stripping voltammetry (ASV) was utilized to simultaneously detect lead (Pb2+), cadmium (Cd2+) and copper (Cu2+). The optimized amounts of mineral oil and AgNP were 80 mu L and 2mg respectively. The calibration curve of the optimized electrode showed a strong line correlation between the heavy metal concentration and the reduction current for Pb2+, Cd2+, and Cu2+. In addition, the limit of detection is 17 parts per billion (ppb) for Cd2+, 12 ppb for Pb2+ and 44 ppb for Cu2+. The optimized electrode was tested on three commercial brands of Puerh tea. Copper metal ions, Cu2+, were found in the tea samples. Lastly, atomic absorption spectroscopy was used to verify the results obtained from ASV.