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carbon-13 (13C)

a naturally occurring isotope of carbon, with an atomic mass of 13, occurring 1.11% of the time. It is used as a tracer in liver function tests and a few metabolic tests.
References in periodicals archive ?
Similarly, scientists add samples of carbon-13 to the soil to assess soil quality.
Carbon-13 NMR spectroscopy delivers more detail in its spectra than use of the more basic 1H nucleus alone.
SAM's mass spectrometer and tunable laser spectrometer independently measured virtually identical ratios of carbon-13 to carbon-12.
The objective of this article was to shed light on the differences between the existing analysis techniques and establish a statistical analysis featuring greater detail on the results of stable carbon-13 and nitrogen-15 isotopes for traceability in birds.
So when the ratio of carbon-12 to carbon-13 decreases, it indicates the presence of the kind of bacteria we are looking for," said Haggblom.
Simpson's research interests and publications are in the areas of polycyclic aromatic hydrocarbons, Carbon-13 labeled compounds and phenolic compounds, especially in grapes and wine.
Future Almaden research is now aimed at further improving the sensitivity, resolution, and speed of the MRFM technique to detect single protons and other nuclei, such as carbon-13, used to reveal molecular structures.
If the Mars samples reveal higher amounts of carbon-12 than carbon-13, it will be strongly indicative of life.
These biases arise from memory effects in ion sources and affect the reliability and comparability of carbon-13 and oxygen-18 measurements used in studies requiring high interlaboratory reproducibility, including research relevant to climate change.
The technology developed by Martek involves the placement of deuterium, carbon-13 and nitrogen-15 labeled isotopes into each amino acid backbone.
Noninvasive tests include serum antibody titers, the carbon-13 urea breath test, and stool testing with either polymerase chain reaction or antigen enzyme immunoassay.