Simultaneous Detection of Trace Heavy Metal Ions Using a Chemically Activated Graphene / Bi Nanocomposites Electrode By Differential Pulse Anodic Stripping Voltammetry

Activated graphene were dispersed in Nafion (AG-NA) solution and used in combination with in situ plated bismuth film electrode for fabricating the enhanced electrochemical sensing platform to determine trace zinc, cadmium and lead by differential pulse anodic stripping voltammetry (DPASV). We report the first example of a bismuth film electrode plated in situ using activated graphene (AG) prepared by KOH activation. The as-synthesized AG-NA/Bi nanocomposite was characterized by X-ray diffraction (XRD), Raman spectroscopy, transmission electron microsopy (TEM) and scanning electron microscopy (SEM). Results are presented regarding the effects of different operational variables such as pre-concentration potential, bismuth deposition time, bismuth concentration, and stirring speed during pre-concentration were optimized for the purpose of determining trace metals in 0.1 M acetate buffer solution (pH 4.5).

In this study, activated graphene – Nafion / Bi composite film were prepared and used for a sensitive and mercury-free electrochemical platform for the analysis of the zinc, cadmium and lead. Liner calibration curves ranged from 10 μg/L to 50 μg/L for zinc and 10 μg/L to 80 μg/L for cadmium and lead. The composite film integrating the advantages of activated graphene, Nafion and bismuth enhanced the sensitivity of trace metal ion, especially zinc. The limit of detection was 1.71 μg/L for lead, 0.71 μg/L for cadmium and 0.60 μg/L for zinc (S/N = 3). The AG-NA/Bi composite film electrodes were successfully applied to analysis of trace metals in real sample.