Isotope fractionation
Isotope fractionation describes fractionation processes that affect the relative abundance of isotopes, a phenomena that occurs (and so advantage is taken of it) in the study geochemistry, biochemistry, food science, and other fields. Normally, the focus is on stable isotopes of the same element. Isotopic fractionation can be measured by isotope analysis, using isotope-ratio mass spectrometry, nuclear magnetic resonance methods (specialised techniques,) cavity ring-down spectroscopy, etc., to measure ratios of isotopes, important tools to understand geochemical and biological systems, past and present. For example, biochemical processes cause changes in ratios of stable carbon isotopes incorporated into biomass.