A novel mimetic peroxidase catalyst by using magnetite-containing silica nanoparticles as carriers

A method for coating magnetite and mimetic enzyme (hemin) with amorphous silica to form a novel mimetic peroxidase (magnetite-hemin/SiO2) has been developed by combining reverse microemulsion and the modified Stober method. The magnetic silica nanoparticle supported hemin has a long-term stability toward temperature and good reusability. They can be easily separated from the reaction solution by using an external magnetic field and reused directly for next round of reaction. The peroxidase activity of the magnetite-hemin/SiO2 was studied based on its catalytic effect on the reaction of p-hydroxyphenylacetic acid and H2O2. The results indicated that the catalytic activity of the new mimetic enzyme catalyst is higher than that of the free hemin. The possibility of its application was proven by the determination of H2O2, with the detection limits of 7.3 nmol L-1 H2O2.