| Determination of δ(18)O and δ(15)N in Nitrate. | |
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MedLine Citation:
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PMID: 21639170 Owner: NLM Status: In-Data-Review |
Abstract/OtherAbstract:
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The analyses of both O and N isotopic compositions of nitrate have many potential applications in studies of nitrate sources and reactions in hydrology, oceanography, and atmospheric chemistry, but simple and precise methods for these analyses have yet to be developed. Testing of a new method involving reaction of potassium nitrate with catalyzed graphite (C + Pd + Au) at 520 °C resulted in quantitative recovery of N and O from nitrate as free CO(2), K(2)CO(3), and N(2). The δ(18)O values of nitrate reference materials were obtained by analyzing both the CO(2) and K(2)CO(3) from catalyzed graphite combustion. Provisional values of δ(18)O(VSMOW) for the internationally distributed KNO(3) reference materials IAEA-N3 and USGS-32 were both equal to +22.7 ± 0.5‰. Because the fraction of free CO(2) and the isotopic fractionation factor between CO(2) and K(2)CO(3) were constant in the combustion products, the δ(18)O value of KNO(3) could be calculated from measurements of the δ(18)O of free CO(2). Thus, δ(18)O(KNO)((3)) = aδ(18)O(free)( )(CO)((2)) - b, where a and b were equal to 0.9967 and 3.3, respectively, for the specific conditions of the experiments. The catalyzed graphite combustion method can be used to determine δ(18)O of KNO(3) from measurements of δ(18)O of free CO(2) with reproducibility on the order of ±0.2‰ or better if local reference materials are prepared and analyzed with the samples. Reproducibility of δ(15)N was ±0.1‰ after trace amounts of CO were removed. |
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Authors:
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K Révész; J K Böhlke; T Yoshinari |
Publication Detail:
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Type: Journal Article |
Journal Detail:
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Title: Analytical chemistry Volume: 69 ISSN: 0003-2700 ISO Abbreviation: Anal. Chem. Publication Date: 1997 Nov |
Date Detail:
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Created Date: 2011-06-06 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 0370536 Medline TA: Anal Chem Country: United States |
Other Details:
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Languages: eng Pagination: 4375-80 Citation Subset: - |
Affiliation:
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U.S. Geological Survey, 431 National Center, Reston, Virginia 20192, and Wadsworth Center, New York State Department of Health, and School of Public Health, State University of New York, Albany, New York 12201. |
Export Citation:
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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