Low-cost voltammetric sensors for robust determination of toxic Cd(II) and Pb(II) in environment and food based on shuttle-like α-Fe2O3 nanoparticles decorated β-Bi2O3 microspheres

Simultaneous determination of multiple heavy metal ions (HMIs) at trace level is of great significance for the environmental protection. Herein, a cost-effective voltammetric sensor was designed for the simultaneous determination of toxic Cd(II) and Pb(II) using shuttle-like α-Fe2O3 nanoparticles decorated β-Bi2O3 microspheres. After introducing the Fe2O3/Bi2O3 nanocomposites, the electroactive surface area and roughness factor increased significantly. The Fe2O3/Bi2O3 nanocomposites exhibited superior electrocatalytic activity than other modified electrodes, probably because the synergistic interaction between Fe2O3 and Bi2O3 greatly facilitated the deposition-stripping process. The Fe2O3/Bi2O3/GCE realized the simultaneous determination of nanomolar Cd(II) and Pb(II) with a wide dynamic range of 0.002–4 μM. Moreover, the Fe2O3/Bi2O3 nanocomposites showed robust stability in the voltammetric responses up to three weeks and excellent selectivity against the potential interfering such as metal ions and biomolecules. The Fe2O3/Bi2O3/GCE was successfully employed to simultaneously detect Cd2+ and Pb2+ from water and milk samples with good recovery.