14 MeV INAA nitrogen determination in coal conversion liquids |
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Authors: | W D Ehmann S R Khalil D W Koppenaal |
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Institution: | (1) Institute for Mining and Minerals Research, P.O. Box 13015, 40583 Lexington, Kentucky, (USA);(2) Department of Chemistry, University of Kentucky, 40506 Lexington, Kentucky, (USA) |
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Abstract: | Fast neutron activation analysis has been used for the direct determination of nitrogen in coal conversion liquids. In our
previous work on coals, solid standards such as N-1-naphthylacetamide. NBS SRM 912 urea and NBS SRM 148 nicotinic acid were
used for nitrogen determinations. In this work, a set of organic liquids was selected and evaluated for use as nitrogen standards
in the analysis of coal-derived liquids. The use of the liquid standards minimizes problems associated with maintaining uniform
irradiation and counting geometries and self absorption differences related to varying matrix densities. The standard liquids
were selected using criteria of high boiling point, well-defined stoichiometry, high-purity, non-hygroscopic nature and simple
C−H−N elemental compositions. Excellent agreement between the 14 MeV INAA data and calculated stoichiometric values has been
demonstrated for liquids with nitrogen contents from 1.89 to 39.95%. The liquid standards have been used to determine nitrogen
in a set of typical coal conversion liquids and several international standards. |
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Keywords: | |
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