Determination of technetium-99 from complex matrix
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Determination of technetium-99 from complex matrix Lixiong Wang • Lei Tang • Tongzai Yang Yanqiu Yang • Liang Yang
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Received: 16 July 2012 Ó Akade´miai Kiado´, Budapest, Hungary 2012
Abstract This paper reports an approach that can be used for efficient separation and determination of 99Tc (as pertechnetate) after contamination of the environment by nuclear materials. The samples were decomposed by fusion in a mixture of potassium hydroxide and potassium nitrate. After fusion, technetium remains as the pertechnetate anion (TcO4-). The technetium was isolated from the sample by technique combining solvent extraction, anion exchange, then, again, solvent extraction. After separation, 99Tc was measured by isotopedilution mass spectrometry with 97Tc as spike. This method yielded nanogram detection limits for 99Tc. Keywords Technetium Pertechnetate Separation Measurement Isotope-dilution mass spectrometry
inductively-coupled plasma mass spectrometry (ICP-MS) [2], resonance ionization mass spectrometry [3], and accelerator mass spectrometry [4]. The use of TIMS for such analysis requires a 97Tc spike. Measurement of 99Tc with TIMS is hindered by isobaric interferences which can be removed by chemical separation only. In this paper, an efficient method for separation and determination of 99Tc (as pertechnetate) is described. Samples were decomposed by fusion with a mixture of potassium hydroxide and potassium nitrate in a Teflon beaker, by heating at 320 °C in a muffle furnace. After fusion of the samples, the technetium was isolated from the sample by solvent extraction, anion exchange, and, again, solvent extraction. 99Tc was then measured by isotopedilution mass spectrometry. 99Tc was determined at concentrations below 1 ng/g by use of this method.
Introduction Fission products are very important signatures of many nuclear activities. The source of the nuclear materials may be determined by measuring fission products and their principal reactants in the same environmental sample. 99Tc is one of several long-lived fission products whose direct detection is hardly feasible because of low specific activity and lowenergy emissions. Mass spectrometry has been found to be the most sensitive technique currently available for determination of 99Tc. Several mass spectrometric methods have been developed for measurement of 99Tc, for example thermal ionization mass spectrometry (TIMS) [1],
Experimental results and discussion Instruments and reagents Thermal ionization mass spectrometry was performed with a MAT 262. The 97Tc spike was prepared in our laboratory. Aqueous solutions were prepared in 18-MX (Milli-Q) water. 2-Butanone was analytical-grade reagent. A 4.5 9 100 mm glass column was packed with Dowex-192 anion-exchange resin. Sample dissolution
L. Wang (&) L. Tang T. Yang Y. Yang L. Yang P.O. Box 919-214, Mianyang 621900, Sichuan, People’s Republic of China e-mail: [email protected]
A mixture of potassium hydroxide, potassium nitrate, and a trace of water, to act as flux, was weighed into the
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