A method and a device for on-chip magnetic resonance spectroscopy is proposed. On-chip magnetic resonance spectroscopy may be applied to non-magnetic as well as magnetic materials which may be solids, liquids, or gases. The method of the present invention is suitable for miniaturized materials analysis such as, for example, micro-fluidics. In an example embodiment, the method relies on the combination of highly efficient spin excitation near on-chip current wires with very sensitive on-chip magnetic sensors. The method and device also allows one to separately detect different types of magnetic particles or molecules.