isotope fractionation (mass fractionation)

When the change in the isotopic abundances of an element are a regular function of the mass difference between the isotopes. Physical or chemical processes can induce such changes. These changes may result from natural or anthropogenic processes and even from the measurement process itself.. Both the mass spectrometer ion source, the detector and the techniques used to prepare samples for mass spectrometry can introduce isotopic (mass) fractionation.. The magnitude of this effect usually increases with increasing fractional mass difference between the isotopes. Consequently the magnitude of the effect is greater for elements with smaller atomic numbers.