How about the high-resolution x-ray photoelectron spectroscopy (HRXPS) and near-edge x-ray absorption of fine structure (NEXAFS)? With these techniques, we have lots of data in transition metal group materials. If you want to know the relative concentrations, contaminations, impurities, qualities and chemical states in your samples, maybe you better perform XPS experiment at the first time. And also if your sample has crystalline phase, you can also do small-angle XRD. Maybe it will be helpful to know your nano-particle quality. But I am not sure these methods are simple in your case.