Antimony nanoparticle-multiwalled carbon nanotubes composite immobilized at carbon paste electrode for determination of trace heavy metals

A nanocomposite based on multiwalled carbon nanotubes (MWCNT) modified with antimony nanopartides (SbNPs) was synthesized chemically and has been applied to construct an electrode using carbon paste as substrate (SbNP-MWCNT). The developed electrode was applied for the determination of trace heavy metals Pb2+ and Cd2+ by square-wave adsorptive stripping voltammetry. The results were compared with those obtained by related electrode configurations such as Sb-film carbon paste electrode (SbF) and Sb-microsphere-multiwalled carbon nanotube composite carbon paste electrode (Sb-microsphere-MWCNT) in model solutions. The analytical signals for Pb2+ and Cd2+ decreased in the order Isb-nanoparticle > ISb-film > ISb-microsphere indicating that the size of the Sb particles on the coating layer influenced the oxidation current signals of Pb and Cd. The detection limits of the analytes were 0.77 mu g L-1 and 0.65 mu g L-1 for Cd2+ and Pb2+, respectively. The designed electrode was tested for the determination of target ions in wheat flour certified reference material, and the results compared well with those obtained by inductively coupled plasma time-of-flight mass spectrometry, showing satisfactory performance of the composite electrode. (C) 2013 Elsevier B.V. All rights reserved.