Metallo-graphene nanocomposite electrocatalytic platform for the determination of toxic metal ions

• Published in: Sensors (Basel, Switzerland) Vol. 11; no. 4; pp. 3970 - 3987
• Main Authors: Willemse, Chandre M, Tlhomelang, Khotso, Jahed, Nazeem, Baker, Priscilla G, Iwuoha, Emmanuel I
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 01.04.2011; Molecular Diversity Preservation International (MDPI)
• Subjects: Cadmium; Carbon; Electrochemistry - instrumentation; Electrochemistry - methods; Electrodes; Fourier transforms; Graphene; Graphite; Graphite - chemistry; Heavy metals; Humans; Ions - analysis; Ions - toxicity; Mass spectrometry; mercury film; Metal Nanoparticles - chemistry; Metals - analysis; Metals - toxicity; Nafion-Graphene nanocomposite; Nanocomposites; Scientific imaging; Sensors; Silicon wafers; square-wave anodic stripping voltammetry; Toxicity; trace metals; Voltammetry; Nafion-Graphene nanocomposite; trace metals; square-wave anodic stripping voltammetry; mercury film
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s110403970

A Nafion-Graphene (Nafion-G) nanocomposite solution in combination with an in situ plated mercury film electrode was used as a highly sensitive electrochemical platform for the determination of Zn(2+), Cd(2+), Pb(2+) and Cu(2+) in 0.1 M acetate buffer (pH 4.6) by square-wave anodic stripping voltammetry (SWASV). Various operational parameters such as deposition potential, deposition time and electrode rotation speed were optimized. The Nafion-G nanocomposite sensing platform exhibited improved sensitivity for metal ion detection, in addition to well defined, reproducible and sharp stripping signals. The linear calibration curves ranged from 1 μg L(-1) to 7 μg L(-1) for individual analysis. The detection limits (3σ blank/slope) obtained were 0.07 μg L(-1) for Pb(2+), Zn(2+) and Cu(2+) and 0.08 μg L(-1) for Cd(2+) at a deposition time of 120 s. For practical applications recovery studies was done by spiking test samples with known concentrations and comparing the results with inductively coupled plasma mass spectrometry (ICP-MS) analyses. This was followed by real sample analysis.