Isotope-ratio mass spectrometry IRMS is a specialization of mass spectrometry , in which mass spectrometric methods are used to measure the relative abundance of isotopes in a given sample. This technique has two different applications in the earth and environmental sciences. The analysis of ' stable isotopes ' is normally concerned with measuring isotopic variations arising from mass-dependent isotopic fractionation in natural systems. On the other hand, radiogenic isotope analysis  involves measuring the abundances of decay-products of natural radioactivity, and is used in most long-lived radiometric dating methods. The isotope-ratio mass spectrometer IRMS allows the precise measurement of mixtures of naturally occurring isotopes.
Radiometric Age Dating
Dating Using Radioactive Decay | Introduction to Chemistry
Carbon dating , also called radiocarbon dating , method of age determination that depends upon the decay to nitrogen of radiocarbon carbon Radiocarbon present in molecules of atmospheric carbon dioxide enters the biological carbon cycle : it is absorbed from the air by green plants and then passed on to animals through the food chain. Radiocarbon decays slowly in a living organism, and the amount lost is continually replenished as long as the organism takes in air or food. Once the organism dies, however, it ceases to absorb carbon, so that the amount of the radiocarbon in its tissues steadily decreases. Because carbon decays at this constant rate, an estimate of the date at which an organism died can be made by measuring the amount of its residual radiocarbon. The carbon method was developed by the American physicist Willard F.
Dating techniques are procedures used by scientists to determine the age of rocks, fossils, or artifacts. Relative dating methods tell only if one sample is older or younger than another; absolute dating methods provide an approximate date in years. The latter have generally been available only since Many absolute dating techniques take advantage of radioactive decay , whereby a radioactive form of an element decays into a non-radioactive product at a regular rate. Others, such as amino acid racimization and cation-ratio dating, are based on chemical changes in the organic or inorganic composition of a sample.
The attributes of naturally decaying atoms, known as radioisotopes, give rise to their multiple applications across many aspects of modern day life see also information paper on The Many Uses of Nuclear Technology. Radioisotopes are used by manufacturers as tracers to monitor fluid flow and filtration, detect leaks, and gauge engine wear and corrosion of process equipment. Small concentrations of short-lived isotopes can be detected whilst no residues remain in the environment. By adding small amounts of radioactive substances to materials used in various processes it is possible to study the mixing and flow rates of a wide range of materials, including liquids, powders, and gases and to locate leaks.