Isotopentransfer

Isotopentransfer is the process by which isotopes are exchanged or redistributed between chemical species, locations, or phases without a change in the elemental composition. It encompasses a range of phenomena in chemistry, physics, environmental science and biology, from simple exchange reactions to diffusion-driven or surface-catalyzed transfers.

In many systems isotopic exchange occurs through reversible reactions, adsorption and desorption, or diffusion between phases. The rate and extent of isotopentransfer are influenced by thermodynamic isotope effects and, in some cases, by kinetic isotope effects, which arise because heavy isotopes form slightly stronger bonds or move more slowly than light ones. These differences can lead to preferential incorporation or release of certain isotopes under given conditions.

Techniques for studying isotopentransfer include mass spectrometry, particularly isotope ratio mass spectrometry (IRMS), which measures isotope abundances, and nuclear magnetic resonance (NMR) spectroscopy for labeled systems. Imaging methods such as secondary ion mass spectrometry (SIMS) can map isotopic distributions in solids. They may be complemented by computational modeling to interpret fractionation and exchange rates.

Applications of isotopentransfer are broad. In chemistry and biochemistry, it is used for tracer experiments and mechanism studies with isotopic labeling. In environmental and geosciences, isotopic transfer helps trace water movement, carbon and oxygen cycling, and pollutant sources. In materials science, it informs understanding of oxygen or hydrogen exchange on catalysts and in oxides, affecting performance and durability.

Common examples include hydrogen–deuterium exchange in water and amines, oxygen-18 exchange in water or carbon dioxide, and carbon-13 labeling in metabolic investigations.