Mass spectrometry (MS) is an analytical technique that relies on the movements of ions in electric and magnetic fields to classify them according to their mass/charge ratio.
The sample is first vaporised and then ionised using one of various techniques. The ions are then passed through electric and magnetic fields in a part of the instrument called the analyser, and are diverted by different amounts according to their mass/charge ratio. Finally, the ions are detected using one of several types of electrical device. The currents obtained are very small and must be amplified.
The mass spectrometer provides qualitative and quantitative information about the atomic and molecular composition of both inorganic and organic materials.