A novel voltammetric sensor for the simultaneous detection of Cd2+ and Pb2+ using graphene oxide/κ-carrageenan/l-cysteine nanocomposite

Abstract

Simultaneous determination of Cd²⁺ and Pb²⁺ was achieved by using graphene oxide/κ-carrageenan/l-cysteine (GO/κ-Car/l-Cys) nanocomposite modified glassy carbon electrode (GCE) by Square Wave Anodic Stripping Voltammetry (SWASV). The morphology and functionalization of the prepared nanocomposite were characterized by XRD analysis, Raman spectroscopy, Field emission scanning electron microscopy and FTIR analysis. Under optimum conditions, outstanding linearity was obtained for both Cd²⁺ and Pb²⁺ in the range from 5 to 50nM with the detection limits as 0.58nM and 1.08nM respectively. The sensitivity calculated from the slope of calibration curve was 1.39μA/nM and 1.32μA/nM for Cd²⁺ and Pb²⁺ respectively. We also carried out multiple metal ion detection, interference of anions and surfactants for the detection of Cd²⁺ and Pb²⁺ ions. The modified electrode has been applied to the detection of Cd²⁺ and Pb²⁺ present in water and milk samples, and the accessed results were satisfactory with that of AAS.

Keywords: Cadmium and lead; Graphene oxide; Metal ion detection; l-cysteine; κ-Carrageenan.