Multiwall carbon nanotube modified by antimony oxide (Sb₂O₃/MWCNTs) paste electrode for the simultaneous electrochemical detection of cadmium and lead ions

In this study, a sensitive and reliable anodic stripping voltammetry (ASV) using a series of multiwall carbon nanotube modified by antimony oxide (Sb₂O₃/MWCNTs) paste electrodes was successfully introduced for the simultaneous electrochemical detection of Cd²⁺ and Pb²⁺ ions. Firstly, a composite of multiwall carbon nanotubes (MWCNTs) was successfully used to preparing a paste electrode. Then, the MWCNTs bulk electrode was further modified with various concentrations of Sb₂O₃ (1, 3, and 4 wt.%, respectively) for improving the cadmium ions (Cd²⁺) and lead ions (Pb²⁺) detection ability. Among the Sb₂O₃/MWCNTs electrodes, the modified electrode by 3 wt.% Sb₂O₃ exhibits remarkable analytical detection for Cd²⁺ and Pb²⁺ by linear sweep anodic stripping voltammetry (LSASV) technique. The proper linear curves of current response versus the concentration of Cd²⁺ (80–150 ppb) and Pb²⁺ (5–35 ppb) could be observed. Interestingly, the analytical sensitivity of the mixture Cd²⁺ and Pb²⁺ were 1.932 and 2.694 μA⋅L⋅μg^–1, respectively, which were higher than 1.5 and 1.3 folds of the individual ions. It expects that the Sb₂O₃/MWCNTs paste electrode could provide a significant improvement to the electrode for the simultaneous electrochemical detection of Cd²⁺ and Pb²⁺ ions.