Carbon-14 by the C urea breath test, which has no radiation issues. Carbon-14 Carbon-14, (C), or radiocarbon, is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons. Its presence in organic materials is the basis of the radiocarbon dating method pioneered by Willard Libby and colleagues (1949) to date archaeological, geological and hydrogeological samples. Carbon-14 was discovered on February 27, 1940, by Martin Kamen and Sam Ruben at the University of California Radiation Laboratory in Berkeley, California. Its existence had been suggested by Franz Kurie in 1934. There are three naturally occurring isotopes of carbon
Hydrogen isotope biogeochemistry samples with more precision. Hydrogen isotope applications quickly emerged in petroleum geochemistry by measuring oil, paleoclimatology by observing lipid biomarkers, and ecology by constructing trophic dynamics. Modern advances are currently underway in the clumped isotope composition of methane after development of the carbonate thermometer. Precise measurements are also enabling focus on microbial biosynthetic pathways involving hydrogen. Ecologists studying trophic levels are especially interested in compound specific measurements for construction of past diets and tracing predator-prey relationships. Highly advanced machines are now promising position specific hydrogen isotope analysis of biomolecules and natural gases. All isotopes of a chemical element contain the