Isotope fractionation become enriched in the liquid phase while the lighter isotopes (O and H) tend toward the vapor phase. Isotope fractionation Isotope fractionation describes processes that affect the relative abundance of isotopes, often used in isotope geochemistry. Normally, the focus is on stable isotopes of the same element. Isotopic fractionation in the natural environment can be measured by isotope analysis, using isotope-ratio mass spectrometry, to separate different element isotopes on the basis of their mass-to-charge ratio, an important tool to understand natural systems. For example, in biochemistry processes cause a fluctuation in the amount of isotopes of carbon ratios incorporated into
Relative atomic mass atomic mass" has attracted considerable controversy since at least the 1960s, mainly due to the technical difference between weight and mass in physics. Still, both terms are officially sanctioned by the IUPAC. The term "relative atomic mass" now seems to be replacing "atomic weight" as the preferred term, although the term ""standard" atomic weight" (as opposed to the more correct ""standard" relative atomic mass") continues to be used. Relative atomic mass is determined by the "average atomic mass", or the weighted mean of the atomic masses of all the atoms of a particular chemical element found in a particular sample,