Glassy carbon electrode modified by graphene–gold nanocomposite coating for detection of trace lead ions in acetate buffer solution

• Graphene with gold nanoparticles was electrodeposited on glassy carbon electrode.
• The prepared electrode was able to detect trace lead ions at nM concentration.
• Interference study against copper confirmed the selectivity of the electrode for lead.
• The prepared electrode showed a promising recovery tested in tap water samples.

Reduced graphene oxide (RGO) decorated with gold nanoparticles (AuNPs) was electrodeposited on glassy carbon electrode (GCE) using cyclic voltammetric method. The results of Raman spectroscopy confirmed the simultaneous formation of AuNPs and reduction of graphene oxide through the electrodeposition process. Scanning electron microscopic measurements showed a uniform distribution of the AuNPs on the RGO sheets. The RGO-AuNP nanocomposite coated GCE (G–Au/GCE) was used to detect lead ions (Pb2+) contained in a 0.1 M acetate buffer solution (pH 5.3) using square wave anodic stripping voltammetry (SWASV). The G–Au/GCE demonstrated higher detection sensitivity and stronger SWASV signals than the bare GCE, with the limit of detection of about 0.8 nM.