单分散羧基化Fe<sub>3</sub>O<sub>4</sub>磁性纳米粒子的制备及表征
摘要
The functionalized monodisperse Fe<sub>3</sub>O<sub>4</sub> magnetic nanoparticles are of importance in the field of biomedical detection and therapy. In this paper, the carboxyl-functionalized monodisperse Fe<sub>3</sub>O<sub>4</sub> magnetic nanoparticles were synthesized by first synthesis of the oleic acid stabilized monodisperse iron oxide nanoparticles, and then the oxidation of oleic acid on the surface of the magnetic nanoparticles by sodium periodate. The nanoparticles were characterized by FT-IR, transmission electron microscopy (TEM), thermogravimetric analyzer (TGA), X-ray diffraction (XRD) and vibrating sample magnetometer (VSM). The experiment results show that the Fe<sub>3</sub>O<sub>4</sub> magnetic nanoparticles have been functionalized by carboxyl group, and the diameter was 12 nm with superparamagnetism at room temperature momodisperse and good dispersion in aqueous solution. The concentration of carboxyl group on the surface of these nanoparticles was determined by TGA and 4-bromomethyl-6,7-dimethyloxycoumarin reaction method, respectively, the data show that the concentration of carboxyl group is on the order of 10<sup>-7</sup> mol/mg.