Effect of pH on ferromagnetic iron oxide nanoparticles

Magnetic oxides, particularly magnetite and maghemite, have been synthesized extensively, due to their scientific and hi-tech importance. Magnetic iron oxide nanoparticles are mainly used for the diagnosis and treatment of diseases. Delivery of iron oxide magnetic nanoparticles to a target site and time period in the sites is a critical step for efficient therapy. These procedures can be controlled by the regulation of exposure to magnetic field. Herein, we report synthesis of magnetic nanoparticles of iron oxide by sol-gel method. Effect of pH on structural and magnetic properties has been investigated. Five sols are synthesized with pH in the range of 1 to 5. X-ray diffraction shows transition of magnetite to maghemite as a function of pH. M-H curves show the transition from superparamagnetic to ferromagnetic behavior, which is consistent with XRD data. (C) 2015 Elsevier Ltd. All rights reserved.