For example, the stable isotopes of carbon include carbon 12 (written as 12C for short, with 6 protons and 6 neutrons) and carbon 13
(13C, with 6 protons and 7 neutrons).
They then separated those moments in which the extinction coincided with sharp fluctuations in the ratio of carbon isotopes 12 to carbon 13
in sedimentary rocks.
The present study was focussed on stable carbon 13
and oxygen 18 isotopic analysis based on data from two stratigraphically importantsections.
Magritek's Spinsolve Carbon is a carbon 13
capable bench-top NMR spectroscopy system that has been designed to meet the needs of specific groups of users.
The biomarker O'Brien and her research group pilot-tested was the ratio of two different carbon atoms--heavy carbon 13
and light carbon 12 --which are incorporated into plants during photosynthesis.
The percentage of carbon 13
in the microfossils was indicative of material produced by biological processes.
Ning (Tsinghua U., China) presents an integrated discussion of the structural identification and interpretation of organic compounds with spectroscopic techniques, covering protonic and carbon 13
NMR spectroscopy; two-dimensional NMR spectroscopy, including COSY, NOESY, ROESY, and TOCSY; mass spectroscopy, including electrospray ionization, CI, FAB, MALDI, and APCI; and infrared spectroscopy.
The BreathID System is a breath-test platform capable of analyzing parts-per-million changes in carbon 13
and carbon 12 ratios in a patient's breath--intended for use in the qualitative detection of urease associated with Helicobacter pylori in the human stomach and as an aid in initial diagnosis and post treatment monitoring of H pylori infection.
Analysis on co-condensation of melamine and urea through carbon 13
enriched formaldehyde with carbon-13 nuclear magnetic resonance spectroscopy.
"But they have different ratios of carbon 13
to carbon 12 to those that have been introduced illicitly."
The technique relies on the injection of polarized carbon 13
, which breaks down and releases energy once in the body.