The Collaborative International Dictionary
mass spectrometry \mass spectrometry\ mass spectroscopy \mass spectroscopy\n. 1. (Physics, Chemistry) A method for identifying chemical composition of substances by use of a mass spectrometer.
Spectrometry \Spec*trom"e*try\, n. (Physics) Art or process of using a spectrometer, of any type; -- when used alone, it usually refers to the use of a spectrometer using light in the visible, infrared, or ultraviolet region. -- Spec`tro*met"ric, a.
mass spectrometry, the art or process of using a mass spectrometer to analyse chemical samples.
n. (context physics analytical chemistry English) An analytical technique that measures the mass / charge ratio of the ions formed when a molecule or atom is ionized, vaporized and introduced into a vacuum. Mass spectrometry may also involve breaking molecules into fragments - thus enabling its structure to be determined.
Mass spectrometry (MS) is an analytical technique that ionizes chemical species and sorts the ions based on their mass to charge ratio. In simpler terms, a mass spectrum measures the masses within a sample. Mass spectrometry is used in many different fields and is applied to pure samples as well as complex mixtures.
A mass spectrum is a plot of the ion signal as a function of the mass-to-charge ratio. These spectra are used to determine the elemental or isotopic signature of a sample, the masses of particles and of molecules, and to elucidate the chemical structures of molecules, such as peptides and other chemical compounds.
In a typical MS procedure, a sample, which may be solid, liquid, or gas, is ionized, for example by bombarding it with electrons. This may cause some of the sample's molecules to break into charged fragments. These ions are then separated according to their mass-to-charge ratio, typically by accelerating them and subjecting them to an electric or magnetic field: ions of the same mass-to-charge ratio will undergo the same amount of deflection. The ions are detected by a mechanism capable of detecting charged particles, such as an electron multiplier. Results are displayed as spectra of the relative abundance of detected ions as a function of the mass-to-charge ratio. The atoms or molecules in the sample can be identified by correlating known masses to the identified masses or through a characteristic fragmentation pattern.