Introduction to Mass Spectrometry Mass spectrometry is a powerful analytical technique used to measure the mass-to-charge ratio of ions. It is used in a wide range of applications, from determining the elemental composition of a sample to analysing the structure of proteins and other large molecules. In mass spectrometry, an ionized sample is introduced into a vacuum chamber, where it is accelerated by an electric field and then passed through an analyser that separates the ions according to ...