Synthesis and application of a natural-based nanocomposite with carbon nanotubes for sensitive voltammetric determination of lead (II) ions.

A modified carbon paste electrode has been developed for the determination of Pb(ΙΙ) ions based on Fe3O4/eggshell magnetic nanocomposite. The structure and morphology of Fe3O4/eggshell were analysed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The prepared nanocomposite was also characterized by Fourier transform infrared spectroscopy (FT-IR) and vibrating sample magnetometer (VSM). The electrochemical procedure was based on the accumulation and determination of Pb(ΙΙ) ions at the surface of the modified carbon paste electrode with Fe3O4/eggshell nanocomposites and carbon nanotubes by differential pulse anodic stripping voltammetry (DPASV). Various experimental parameters involved in the preconcentration of Pb(ΙΙ) ions and voltammetric stripping step were studied. Under the optimum conditions, the voltammetric peak current of Pb(ΙΙ) occurs at a potential about −0.5 V. Also, the voltammetric peak current increased linearly with Pb(ΙΙ) concentration in the range of 0.5–200 ng mL−1 and a detection limit of 0.15 ng mL−1 was obtained for Pb(ΙΙ). The selectivity of the proposed electrode for Pb(ΙΙ) ions in the presence of some cations was also examined. The practical application of the proposed modified electrode was evaluated by the determination of Pb(ΙΙ) ions in human hair and water samples. The results were satisfactory for the spiked samples. [ABSTRACT FROM AUTHOR]