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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...

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Detalles Bibliográficos
Autores principales: Isbell, Horace S., Frush, Harriet L., Peterson, Ruth A.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: [Gaithersburg, MD] : U.S. Dept. of Commerce, National Institute of Standards and Technology 1959
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
Descripción
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.