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 nanoparticles (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 (Sbmicrosphere-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 μg L−1 and 0.65 μg 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.