FLUOROMETRIC DETERMINATION OF HYDROGEN PEROXIDE USING Fe3O4 MAGNETIC NANOPARTICLES AS A MIMETIC ENZYME

Hydrogen peroxide（H2O2）is used as a chemical in many food industries and excessive residual H2O2 in the food will cause harm to people's health. To establish a simple, low-cost and accurate analytical methods to detect H2O2 by using metal oxide nanoparticle as mimetic enzyme. In this paper, we utilized the instinct peroxidase-like property of Fe3O4 magnetic nanoparticles (Fe3O4MNPs) to establish a fluorescence assays of H2O2 and benzoic acid (BA) as indicator. Fe3O4MNPs were prepared by co-precipitation and characterized using TEM, magnetization and N2-BET surface area measurement. The fluorescence of system (with excitation/emission peaking at 294/411 nm) was enhanced on increasing the concentration of H2O2 due to form hydroxybenzoic acid. Under optimized conditions, the system gave a ratiometric fluorometric response in the 0.5 to 12.5 μM H2O2 with a 0.122 μM limit of detection. The Ea and Km for the reaction of H2O2 with the Fe3O4MNPs were respectively calculated to be 44.65 kJ/mol and 234.30 mM. The system is highly sensitive and selective toward H2O2 which the relative standard deviation (RSD) of samples was 4.86% (n=6). The proposed method provides a quick, easy and cheap way and was applied to the determination of H2O2 in disposable chopsticks with satisfactory results. The average hydrogen peroxide content in disposable chopsticks was 2.321±0.32 mg/kg. The method for H2O2 determination described here would be of great value in food and agricultural industry.