Polysulfide/Graphene Nanocomposite Film for Simultaneous Electrochemical Determination of Cadmium and Lead Ions

An integrative electroanalytical method was developed for detecting Cd 2 + and Pb 2 + ions in aqueous solutions. Polysulfide/graphene (RGO-S) nanocomposites were prepared and their performance as electrochemical sensors for Cd 2 + and Pb 2 + was evaluated. The RGO-S nanocomposite was carefully characterized by scanning electron microscopy with energy-dispersive X-ray spectrometry, transmission electron microscopy, and X-ray photoelectron spectroscopy. The as-prepared RGO-S was incorporated into a pyrolytic graphite electrode (RGO-S/PGE) and used for detecting trace amount of Cd 2 + and Pb 2 + by differential pulse anodic stripping voltammetry. Under optimal conditions, the stripping peak current of RGO-S/PGE varies linearly with heavy metal ion concentration in the ranges 2.0–300 μ g L − 1 for Cd 2 + and 1.0–300 μ g L − 1 for Pb 2 + . The limits of detection for Cd 2 + and Pb 2 + were estimated to be about 0.67 μ g L − 1 and 0.17 μ g L − 1 , respectively. The prepared electrochemical heavy-metal-detecting electrode provides good repeatability and reproducibility with high sensitivity, making it a suitable candidate for monitoring Cd 2 + and Pb 2 + concentrations in aqueous environmental samples.