Facile Strategy for Electrochemical Analysis of Hydrogen Peroxide Based on Multifunctional Fe₃O₄@Ag Nanocomposites

The authors are presenting the application of Fe₃O₄@Ag nanocomposites to a highly sensitive and selective analysis of hydrogen peroxide (H₂O₂). The morphology and structure of the synthesized porous Fe₃O₄ nanoparticles and Fe₃O₄@Ag nanocomposites are well-characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD), UV-vis absorption spectrum, etc. The nanocomposites can be facilely modified on the magnetic glassy carbon electrode, which also exhibit a sharp silver stripping peak owing to the loaded Ag nanoparticles. Since an autocatalytic oxidation reaction of Ag nanoparticles occurs with the existence of H₂O₂, the peak current intensity is suitable to track H₂O₂ levels. The analytical performance is evaluated by the technique of linear sweep voltammetry, which shows a linear range from 0.5 to 20 μM. The limit of detection is as low as 0.16 μM. The detection can be completed in 5 min, which is quite fast and convenient. In addition, an electrochemical track of H₂O₂ released from living cells is also achieved. Therefore, the potential applications in biological studies and disease theranostics are promised.