Facile Strategy for Electrochemical Analysis of Hydrogen Peroxide Based on Multifunctional Fe 3 O 4 @Ag Nanocomposites.

The authors are presenting the application of Fe 3 O 4 @Ag nanocomposites to a highly sensitive and selective analysis of hydrogen peroxide (H 2 O 2 ). The morphology and structure of the synthesized porous Fe 3 O 4 nanoparticles and Fe 3 O 4 @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 H 2 O 2 , the peak current intensity is suitable to track H 2 O 2 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 H 2 O 2 released from living cells is also achieved. Therefore, the potential applications in biological studies and disease theranostics are promised.