This paper deals with the characterization of magnetic iron oxide nanoparticles. Pure magnetite (Fe3O4) and noble metal doped magnetite were synthesized following a new sustainable microwave-assisted method. Furthermore, an experimental analysis was carried out to investigate the chemical and magnetic properties of these new nanopowders. Morphological and chemical characteristics of the pure magnetite and magnetite modified by noble metals such as palladium, platinum and ruthenium are provided together with the relevant B-H magnetic curve. Among the adopted measurement techniques, the purity of magnetite phase was analyzed via Fourier Transform Infrared Spectroscopy (FT-IR) and X-Ray Diffraction (XRD), while a Vibrating Sample Magnetometer (VSM) characterized the magnetic behavior of the nanopowder samples