Simultaneous Determination of Total Carbon, Nitrogen, Hydrogen and Sulfur in Twenty-seven Geological Reference Materials by Elemental Analyser

Autor: Ran Kubota
Rok vydání: 2009
Předmět:
Zdroj: Geostandards and Geoanalytical Research. 33:271-283
ISSN: 1751-908X
1639-4488
DOI: 10.1111/j.1751-908x.2009.00905.x
Popis: The contents of total carbon, hydrogen, nitrogen and sulfur in twenty-seven geological reference materials, issued by five producer organisations (USGS, CCRMP, ANRT, NIST and GSJ) were determined using an automated simultaneous elemental analyser following combustion. In order to complete gasification of C and N in some geological materials, the combustion temperature needed to be greater than 1150 °C. The calibrator prepared from known amounts of reagent material was not adopted for more than 1.2% m/m of H. Unrealistically high values in certain materials supposed to contain less than 1000 μg g−1 S may be due mainly to memory effects. The limit of detection was 50 μg g−1 for C and N, 500 μg g−1 for H and 1000 μg g−1 for S. Although the blank value of C and N was always stable and less than one third of the detection limit, it had a slightly higher value for N and S. By repeating long-term analysis, high reproducibility for each of the four elements was verified. The method has been applied satisfactorily to a variety of geological reference materials, and recommended values for C, H and N for most of the reference materials studied have been tabulated. Les teneurs en carbone total, hydrogene, azote et soufre de vingt sept materiaux geologiques de reference, proposes par cinq producteurs (USGS, CCRMP, ANRT, NIST et GSJ) ont ete determinees en utilisant, apres combustion, un analyseur elementaire simultane, automatique. Afin d'assurer la transformation gazeuse de C et N dans certains materiaux geologiques, la temperature de combustion devait etre superieure a 1150 °C. La solution de calibration preparee a partir de quantites connues de reactifs s'est revelee de pas etre adaptee a des concentrations en H superieures a 1.2% m/m. Les valeurs tres elevees, et irrealistes, obtenues sur certains materiaux qui etaient supposes contenir moins de 1000 μg g−1 de S etaient peut-etre dues a des effets memoire. Les limites de detection etaient de 50 μg g−1 pour C et N, 500 μg g−1 pour H et 1000 μg g−1 pour S. Bien que le blanc de C et N soit stable et inferieur a un tiers de la limite de detection, il lui etait legerement superieur pour N et S. Une tres bonne reproductibilite (et stabilite) sur le long terme a ete verifiee pour les quatre elements. La methode a ete appliquee de facon satisfaisante a differents materiaux geologiques de reference, et des valeurs recommandees pour C, H, N dans presque tous les materiaux de reference ont ete compilees.
Databáze: OpenAIRE
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