Use of the optogalvanic effect (OGE) for isotope ratio spectrometry of 13CO2 and 14CO2 |
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Authors: | Daniel E Murnick Joseph O Okil |
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Institution: | 1. Department of Physics , Rutgers University , Newark, NJ, 07102, USA murnick@newark.rutgers.edu;3. Department of Physics , Rutgers University , Newark, NJ, 07102, USA |
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Abstract: | The use of isotopic carbon dioxide lasers for determination of carbon (and oxygen) isotope ratios was first demonstrated in 1994. Since then a commercial device called LARA?, has been manufactured and used for Helicobacter pylori breath tests using 13C-labelled urea. The major advantages of the optogalvanic effect compared with other infrared absorption isotope ratio measurement techniques are its lack of optical background and its high sensitivity resulting from a signal gain proportional to laser power. Continuous normalisation using two cells, a standard and sample, lead to high accuracy as well as precision. Recent advances in continuous flow measurement of 13C/12C ratios of CO2 in air and extensions of the technique to 14C, which can be analysed as a stable isotope, are described. |
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Keywords: | Carbon-13 Carbon-14 Carbon dioxide Optogalvanic detection IR spectrometry Isotope analysis Isotopic carbon dioxide lasers |
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