Stable isotopes are commonly used for light elements (hydrogen, carbon, nitrogen and oxygen), which are precisely the most abundant in the environment. These elements are characterized by the largest natural variations in isotope ratios (abundance ratio between heavy and light isotope) due to be suffering greater isotopic fractionation in a wide range of physical and chemical processes.
In many cases the accurate determination of these relationships opens the possibility of differentiating materials or compounds that are chemically indistinguishable.
The most common type of samples in the laboratory and its main applications can be summarized in the following fields:
BIOLOGY AND ECOLOGY: 15N and 13C in plant and animal tissues. Determination of food webs.
AGROBIOLOGY: 15N and 13C in soils, plants, leachate and gas. Efficiency of fertilizer. Nitrogen metabolism. Fertigation. Water stress, fertilization and pruning treatments.
VETERINARY AND ANIMAL PRODUCTS: 15N in feed, rumen extracts, animal tissue, etc.. (Metabolic studies, improved feed, etc.)..% D in animal fluids (Deut. Of body water content).
HYDROLOGY: D, 18O, 15N and 13C in water and dissolved species. Identification of areas and aquifer recharge rates, flow depth, characterization of rain, the origin of salts, pollution sources, and so on.
PALEOCLIMATOLOGY: 13C and 18O in speleothems, travertine and shells and land (climate change studies and paleoenvironments).
ARCHAEOLOGY: 13C bone collagen from animals and humans (study palaeodiet and migrations). 13C and 18O composition in fossil shells and bones.
ENVIRONMENTAL SCIENCE: Isotopic studies of 13C and 15N in oil derivatives and in atmospheric CO2 (characterization, identification of pollution sources). D, 13C, 15N and 18O water pollutants (identification of pollution sources).
FOOD FRAUD DETECTION: By product characterization and comparison with natural isotopic compositions (addition of sugar to water or juice). 13C honey (total protein fraction to identify potential exogenous sugar).
FORENSIC ANALYSIS: Detection of natural or synthetic drugs of abuse (cocaine), management of doping in athletes (exogenous testosterone) of origin (factory) of explosives, etc.