Encyclopedia of Astrobiology

Living Edition
| Editors: Muriel Gargaud, William M. Irvine, Ricardo Amils, Henderson James Cleaves, Daniele Pinti, José Cernicharo Quintanilla, Michel Viso


  • Jennifer C. SternEmail author
Living reference work entry
DOI: https://doi.org/10.1007/978-3-642-27833-4_595-2



Fractionation is the partitioning of a chemical species into two or more phases based on its chemical or physical properties. The chemical or isotopic composition of each phase may reflect an enrichment or depletion in one element or isotope with respect to the others, which can yield information about the mechanism of formation. Fractionation can be caused by differences in mass and binding energy and by biochemical reactions, which alter the ratio of one element or isotope to another. For example, fractionation of stable carbon isotopes can provide information on the biotic or abiotic origin of some organic compounds, as photosynthetic reactions process the lighter isotope, 12C, more rapidly than 13C, resulting in enrichment in 12C of its products.

See Also


Organic Compound Binding Energy Isotopic Composition Exchange Reaction Isotopic Ratio 
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Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  1. 1.Planetary Environments LaboratoryNASA Goddard Space Flight CenterGreenbeltUSA