Isotopes mass spectrometry Radiocarbon

Soon after this discovery the harnessing of the technique to the measurement of all the U isotopes and all the Th isotopes with great precision immediately opened up the entire field of uranium and thorium decay chain studies. This area of study was formerly the poaching ground for radioactive measurements alone but now became part of the wonderful world of mass spectrometric measurements. (The same transformation took place for radiocarbon from the various radioactive counting schemes to accelerator mass spectrometry.)... 

A more recently developed technique, known as the accelerator mass spectrometry (AMS) radiocarbon dating technique, based on counting, in a mass spectrometer, the relative amount of radiocarbon to stable carbon isotopes in a sample (see Textbox 10). 

Ironically, our current plans call for the reverse linkage of the above enrichment procedures. That is, we shall use an electromagnetic isotope separator to enrich argon isotopes for a mass spectrometry experiment, and we shall enrich radiocarbon via thermal diffusion for improved mini-gas proportional counting. 

Currie, L. A., Klouda, G. A., Elmore, D., Ferraro, R., Gove, H., Accelerator Mass Spectrometry and Electromagnetic Isotope Separation for the Determination of Natural Radiocarbon at the Microgram Level (in preparation). 

Determination of isotopic abundance by mass spectrometry is a universally employed method. For example, it is possible to determine the geographic source of plant-based organic compounds or mineral compounds, or even to improve the precision of radiocarbon dating using the isotopic signature of a species. 

D6866-04a Standard test methods for determining the bio-based content of natural range materials using radiocarbon and isotope ratio mass spectrometry analysis... 

ASTM D6866-06, Standard Test Methods for Determining the Biobased Content of Natural Range Materials Using Radiocarbon and Isotope Ratio Mass Spectrometry Analysis, American Society for Testing and Materials, 2006, p. 14. 

Plate 22 Radiocarbon dating. View of a linear accelerator used as part of an accelerator mass spectrometer (AMS). This device is capable of counting the relatively few carbon-14 atoms in a radioactive sample. The proportion of carbon-14 to carbon-12 atoms in the sample may be used to determine the radiocarbon age of an organic object. This is then adjusted by various corrections to give the true age. See Isotope Ratio Studies Using Mass Spectrometry. Reproduced with permission from Science Photo Library. 

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