Abstract: A method for the preparation of magnetic nanoparticles coated with a noble metal is described. The method includes providing a first mixture containing a first non-polar organic solvent and uncoated magnetic nanoparticles. The first mixture is mixed with a second mixture containing a second non-polar organic solvent and ions comprising the noble metal to form a third mixture. The third mixture is mixed with an organic ligand or a fourth mixture containing an organic ligand to form a fifth mixture. The fifth mixture is reacted with a sixth mixture containing a reducing agent to form a seventh mixture containing the monodispersed magnetic nanoparticles coated with the noble metal. The monodispersed magnetic coated nanoparticles may be separated from the seventh mixture by adding a polar organic solvent or a mixture of polar organic solvents in which the nanoparticles are insoluble.