Determination of hydrogen peroxide with the aid of peroxidase-like Fe3O4 magnetic nanoparticles as the catalyst

As a mimetic peroxidase, Fe3O4 magnetic nanoparticles (MNPs) were prepared and used for the determination of hydrogen peroxide (H2O2) based on their catalytic effect on the oxidation of N,N-diethyl-p-phenylenediamine sulfate (DPD). Fe3O4 MNPs were found to be able to activate H2O2 and oxidize DPD to a colored product with a strong absorption maximum at 550 nm. Under optimized conditions, the absorbance of the product responded linearly to H2O2 concentration in the range from 0.5 to 150 x 10(-6) mol L-1 H2O2 with a detection limit as low as 2.5 x 10(-7) mol L-1. The method was successfully applied to the determination of H2O2 in rainwater, honey and milk samples.