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U/
U isotopic analysis of trace uranium in safeguards environmental samples using multicollector inductively coupled plasma mass spectrometryTomita, Jumpei; Tomita, Ryohei; Suzuki, Daisuke; Yasuda, Kenichiro; Miyamoto, Yutaka
Journal of the American Society for Mass Spectrometry, 35(6), p.1178 - 1183, 2024/05
Times Cited Count：1 Percentile：15.28(Biochemical Research Methods)A sensitive analytical technique was investigated in order to determine 10
order of U/U ratio in the sub-ng of uranium using a multi-collector ICP-MS. First, the solution volume was concentrated to one tenth to obtain higher intensities. Next, data acquisition was started from the beginning of the solution uptake and continued until all solution was exhausted. Taking advantage of multi-collector measurement, all data were used with excepting the portion affected by air mixing at the beginning and end of sample introduction. The isotope ratios were calculated from the total counts of each isotope. This technique was applied to U isotope standard (IRMM-184) to measure the 10 order of U/U ratio in the sub-ng of uranium. Measured values were in good agreement with the certified value within the uncertainity (
=2). The uncertainties obtained with this new technique (32% on average) were revised to be 10 times smaller than those obtained with the conventionalmethod.
Tomita, Jumpei; Tomita, Ryohei; Suzuki, Daisuke; Yasuda, Kenichiro; Miyamoto, Yutaka
no journal, ,
Isotopic ratios of uranium particle provide us with the information on the nuclear activities such as enrichment and reprocessing. Precise determination of U isotopic ratios is difficult due to the low intensity of U measured by Faraday cup when pico-gram quantities of uranium was measured by MC-ICP-MS. In this study, the sensitive measurement of the 1-20 pg of uranium was examined. The solution was prepared by only 0.2 mL, which was one-tenth compared to the conventional method, to increase U concentration. Data acquisition was started from the beginning of the solution uptake and continued until all solution was exhausted. The isotopic ratios of uranium were calculated from the total counts of each isotope excepting the portion affected by air mixing at the beginning and end of sample introduction. Uranium isotopic ratios of CRM U015 and IRMM184 determined by this method examined in this study were agreed with the certified values within the uncertainties (2-sigma). The uncertainties obtained by this method were smaller than those by the conventional method.
Tomita, Jumpei; Tomita, Ryohei; Suzuki, Daisuke; Yasuda, Kenichiro; Miyamoto, Yutaka
no journal, ,
The impact of the uranium from the process blank for a single uranium particle analysis by MC-ICP-MS was evaluated quantitatively. The synthetic uranium particles prepared by impregnating of U (NBL CRM U100) to porous silica were used in this study. A conical-bottom bottle was used to dissolve a uranium particle with a small amount of acid. The amount of U and 
U/U of the process blank were 0.2 pg and 0.0190, respectively. This ratio was similar to that of CRM U015 (0.0155), which was used for the detector calibration of MC-ICP-MS, indicating that the process blank was derived from ultra-trace level of uranium remining in the desolvator. The analytical results indicated that the U/U ratio could be determined accurately by MC-ICP-MS when the particle contained more than 23 pg of U.
Tomita, Jumpei; Tomita, Ryohei; Suzuki, Daisuke; Yasuda, Kenichiro; Miyamoto, Yutaka
no journal, ,
no abstracts in English
Tomita, Jumpei; Tomita, Ryohei; Suzuki, Daisuke; Yasuda, Kenichiro; Miyamoto, Yutaka
no journal, ,
Plutonium isotopic standard solution was impregnated into porous silica particles to prepare the Pu particles utilized for a single particle analysis for safeguards. SEM-EDS analysis showed that the prepared silica particles contained Pu. The isotope ratios of the Pu particles were determined with a multi-collector ICP-MS after decomposing individually. 
Pu/
Pu measured ratios agreed with the certified value within the 2
of standard deviation.
Tomita, Jumpei; Tomita, Ryohei; Suzuki, Daisuke; Yasuda, Kenichiro
no journal, ,
no abstracts in English
Tomita, Jumpei; Tomita, Ryohei; Suzuki, Daisuke; Yasuda, Kenichiro; Miyamoto, Yutaka
no journal, ,
Formation of polyatomic interferences made of an atom of heavy element and atoms in plasma such as argon and oxygen is known to create problems for their measurements using ICP-MS. In this study, quantitative assessment of polyatomic interferences for the measurement of U and Pu isotope ratios at ultra-trace level using MC-ICP-MS was conducted. For U isotopes, significant polyatomic interferences caused by 
Ir
Ar, 
PtAr and 
PtAr were observed at the mass of 233, 234 and 236, respectively. When 1 ppb of natural uranium solution (IRMM184) containing 0.4 ppb of Pt was measured, 
U/U isotope ratio was roughly estimated to be two-fold higher than certified value due to the interference. For Pu isotopes, small interference from Pb (
PbAr) was observed at the mass of 244 while other obvious interferences were not found.
