Superparamagnetic iron oxide nanoparticles (SPIONs) stabilised with oleic acid were prepared using thermal decomposition. The NPs were highly monodisperse with a size of 12 ± 2 nm (as measured from TEM analysis, Fig. , ESI †) and χ m of 38 emu.g -1 at 20,000 Oe, normalised against total mass of particle, and confirmed to be superparamagnetic (Fig. , ESI †). While hydrophilic SPIONs usually report a χ m of approx. 70 emu.g -1 at 20,000 Oe, in this case the χ m is lower due to the presence of non-magnetic oleic acid contributing to the sample mass. 6,83