Mass spectrometry
Proteomics · Biochemistry · Biotechnology
Say it: MAS spek-TROM-uh-tree
Mass spectrometry is an analytical technique that turns molecules into charged ions and sorts them by mass-to-charge ratio to identify and measure them.
Also: mass spec
Definition
What is mass spectrometry?
Mass spectrometry identifies substances by weighing their ions. The sample is first given an electric charge in an ion source, a mass analyzer then separates the resulting ions by their mass-to-charge ratio (m/z), and a detector counts how many arrive at each value. The result, a mass spectrum, plots signal intensity against m/z, and its peaks reveal the mass of the intact molecule and of the fragments it breaks into.
Large biological molecules need gentle ionization. Electrospray ionization sprays a liquid sample, often straight from a liquid chromatography column, while MALDI fires a laser at a sample dried onto a matrix. In proteomics, proteins are usually digested into peptides with trypsin and analyzed by tandem mass spectrometry (MS/MS): chosen peptide ions are broken apart, and the fragment pattern is matched against protein databases to work out the peptide sequence and name the protein.
Beyond proteomics, mass spectrometry is used to work out the structure of small organic compounds, measure metabolites, screen newborns for inherited metabolic disorders and detect drugs and poisons in forensic toxicology.
Word parts
Where does the term “mass spectrometry” come from?
- spectr-
- appearance, imageLatin spectrum
- -metry
- measuringGreek metron (measure)
Practice it
Where you'll meet it
Related
Terms that go with it
- ProteomicsProteomics is the large-scale study of the proteome, the full set of proteins in a cell, tissue or organism, including their amounts, changes and interactions.
- ProteinA protein is a large molecule made of one or more chains of amino acids, folded into a specific shape that determines its job in the body.
- Peptide bondA peptide bond is the covalent link that joins the carboxyl group of one amino acid to the amino group of the next, releasing a water molecule.
- Post-translational modificationA post-translational modification is a chemical change made to a protein after it is built on the ribosome, often altering its activity or location.
- MetabolismMetabolism is the full set of chemical reactions in a cell or organism, both those that break molecules down for energy and those that build them up.
Sources
Checked against
Written for biofideX in plain words, after checking these references:
- NCBI MeSH: Mass Spectrometry
- OpenStax Organic Chemistry, 12.1 Mass Spectrometry of Small Molecules
- Introduction to Computational Proteomics, PLoS Computational Biology
Last updated
Spotted a mistake? Tell us and we'll correct it.
Practice Proteomics
Free proteomics quizzes, with an explanation for every answer.
See the Quizzes