Isotope-ratio mass spectrometry isotopic make up of the sample is obtained. For example, carbon isotope ratios are measured relative to the international standard for C. The C standard is produced from a fossil belemnite found in the Peedee Formation, which is a limestone formed in the Cretaceous period in South Carolina, U.S.A. The fossil is referred to as VPDB (Vienna Pee Dee Belemnite) and has C:C ratio of 0.0112372. Oxygen isotope ratios are measured relative the standard, V-SMOW (Vienna Standard Mean Ocean Water). It is critical that the sample be processed before entering the mass spectrometer so that only a single chemical species
Isotopes of nobelium 54 s activity was actually due to No and the isotope No was retracted. Isotopes of nobelium Nobelium (No) is a synthetic element, and thus a standard atomic weight cannot be given. Like all synthetic elements, it has no stable isotopes. The first isotope to be synthesized (and correctly identified) was No in 1966. There are 12 known radioisotopes, which are No to No and No, and 3 isomers, No, No, and No. The longest-lived isotope is No with a half-life of 58 minutes. The longest-lived isomer is No with a half-life of 1.7 seconds. This cold fusion reaction was