Reduced graphene oxide decorated with tin nanoparticles through electrodeposition for simultaneous determination of trace heavy metals

Reduced graphene oxide (RGO) decorated with tin nanoparticles (SnNPs) was electrodeposited on glassy carbon sheet (GCS), i.e. G-Sn/GCS, with a drop-casting method followed by constant potential electroreduction. Raman spectroscopic analysis on the graphitic structure of the G-Sn/GCS confirmed a good intercalation of SnNPs in the RGO matrix. Field emission scanning electron microscopic measurements illustrated a uniform distribution of the SnNPs on the RGO sheets. The G-Sn/GCS showed a better electroanalytical performance than the bare GCS and RGO/GCS in the simultaneous determination of divalent cadmium ions (Cd2+), lead ions (Pb2+) and copper ions (Cu2+) using square wave anodic stripping voltammetry. The electroanalytical measurements using the G-Sn/GCS were optimized at −1 V for 150 s in a 0.1 M acetate buffer solution (pH 5). The G-Sn/GCS demonstrated a highly linear behavior in the detection of Cd2+, Pb2+ and Cu2+ in the concentration range of 10 nM to 100 nM with detection limits of 0.63 nM, 0.60 nM and 0.52 nM (S/N=3), respectively. A mechanism for the formation of the G-Sn nanocomposite was proposed in this paper.