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Mass Spectrometry



technique or series of techniques for separating a mixture into its components

electron impact

method for producing positive ions in mass spectrometry, resulting from bombardment of a molecule with high-energy electrons

electrospray ionization

technique used in mass spectrometry to produce ions by applying a high voltage to a liquid to create an aerosol

exact molecular mass

actual mass of a molecule calculated to four decimal places and obtained by high-resolution mass spectrometry


dissociation of a molecule because of high-energy impact in mass spectrometry

fragmentation pattern

pattern of ions produced by fragmentation of the molecular ion during mass spectrometry

gas chromatography

analytical method in which a compound is vaporized and separated into its components

high-resolution mass spectrometry

mass spectrometry method that allows for precise measurement of a molecule's mass

liquid chromatography

analytical method in which a compound dissolved in a solvent is separated into its components

m/z ratio

ratio of an ion's mass (m) to its charge (z)

M+ + 1 peak

peak on a mass spectrum that is used to determine the number of carbon atoms in a molecule

M+ peak

peak on a mass spectrum indicating the molecular ion, sometimes called the parent ion

mass spectrometry

analytical method in which a molecule is ionized and the resulting fragments and ions are analyzed

matrix-assisted laser desorption/ionization (MALDI)

mass spectrometric method used in determining the amino acid sequence of larger biomolecules

McLafferty rearrangement

reaction in which a molecule containing a keto group breaks apart and an H atom transfers from one fragment to another

molecular formula

formula indicating the number of atoms of each type of element in a molecule

molecular ion

ion formed by removal or addition of an electron without compromising the molecular structure

nominal molecular mass

sum of the mass numbers of a molecule's constituent atoms