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Tritium-Labeled Compounds I. Radioassay of Tritium-Labeled Compounds in “Infinitely Thick” Films With a Windowless, Gas-Flow, Proportional Counter
A simple, sensitive, and reliable technique has been devised for the radioassay of nonvolatile, water-soluble tritium compounds. The substance to be analyzed is dissolved in an aqueous solution of a thickening agent, preferably sodium O-(carboxymethyl) cellulose or sodium alginate. The solution is p...
Autores principales: | , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
[Gaithersburg, MD] : U.S. Dept. of Commerce, National Institute of Standards and Technology
1959
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5287200/ https://www.ncbi.nlm.nih.gov/pubmed/31216149 http://dx.doi.org/10.6028/jres.063A.011 |
Sumario: | A simple, sensitive, and reliable technique has been devised for the radioassay of nonvolatile, water-soluble tritium compounds. The substance to be analyzed is dissolved in an aqueous solution of a thickening agent, preferably sodium O-(carboxymethyl) cellulose or sodium alginate. The solution is placed in a shallow planchet, and after evaporation of the water, the resulting film, which is “infinitely thick” to tritium beta particles, is counted with a 2π, windowless, gas-flow, proportional counter. By means of an empirical factor, determined with a substance of known radioactivity, the counts are converted to microcuries. In a film having a thickness of 0.7 mg/cm(2), the counting efficiency is about 4 percent; the standard deviation from the mean, obtained in a series of routine measurements, was less than 2 percent. An assay can readily be made with tritium-containing material having 0.01 microcurie of radioactivity. The method, which is applicable to nonvolatile, water-soluble solids, solutions, or liquids, is suitable for routine analyses. |
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