Chemical Separation of Uranium and Precise Measurement of <sup>234</sup>U/<sup>238</sup>U and <sup>235</sup>U/<sup>238</sup>U Ratios in Soil Samples Using Multi Collector Inductively Coupled Plasma Mass Spectrometry
Nimelan Veerasamy,
Asako Takamasa,
Rajamanickam Murugan,
Sharayu Kasar,
Tatsuo Aono,
Kazumasa Inoue,
Masahiro Fukushi,
Sarata Kumar Sahoo
Affiliations
Nimelan Veerasamy
Environmental Radionuclide Research Group, National Institutes for Quantum and Radiological Science and Technology (QST), 4-9-1 Anagawa, Inage-Ku, Chiba 263-8555, Japan
Asako Takamasa
Environmental Radionuclide Research Group, National Institutes for Quantum and Radiological Science and Technology (QST), 4-9-1 Anagawa, Inage-Ku, Chiba 263-8555, Japan
Rajamanickam Murugan
Environmental Radionuclide Research Group, National Institutes for Quantum and Radiological Science and Technology (QST), 4-9-1 Anagawa, Inage-Ku, Chiba 263-8555, Japan
Sharayu Kasar
Environmental Radionuclide Research Group, National Institutes for Quantum and Radiological Science and Technology (QST), 4-9-1 Anagawa, Inage-Ku, Chiba 263-8555, Japan
Tatsuo Aono
Environmental Radionuclide Research Group, National Institutes for Quantum and Radiological Science and Technology (QST), 4-9-1 Anagawa, Inage-Ku, Chiba 263-8555, Japan
Kazumasa Inoue
Department of Radiological Sciences, Tokyo Metropolitan University, 7-2-10 Higashiogu, Arakawa-ku, Tokyo 116-8551, Japan
Masahiro Fukushi
Department of Radiological Sciences, Tokyo Metropolitan University, 7-2-10 Higashiogu, Arakawa-ku, Tokyo 116-8551, Japan
Sarata Kumar Sahoo
Environmental Radionuclide Research Group, National Institutes for Quantum and Radiological Science and Technology (QST), 4-9-1 Anagawa, Inage-Ku, Chiba 263-8555, Japan
A new chemical separation has been developed to isolate uranium (U) using two UTEVA columns to minimize iron and thorium interferences from high background area soil samples containing minerals like monazites and ilmenite. The separation method was successfully verified in some certified reference materials (CRMs), for example, JSd-2, JLk-1, JB-1 and JB-3. The same method was applied for purification of U in Fukushima soil samples affected by the Fukushima dai-ichi nuclear power station (FDNPS) accident. Precise and accurate measurement of 234U/238U and 235U/238U isotope ratios in chemically separated U were carried out using a multi-collector inductively coupled plasma mass spectrometer (MC-ICP-MS). In this mass spectrometric method, an array of two Faraday cups (1011 Ω, 1012 Ω resistor) and a Daly detector were simultaneously employed. The precision of U isotope ratios in an in-house standard was evaluated by replicate measurement. Relative standard deviation (RSD) of 234U/238U and 235U/238U were found to be 0.094% (2σ) and 0.590% (2σ), respectively. This method has been validated using a standard reference material SRM 4350B, sediment sample. The replicate measurements of 234U/238U in SRM shows 0.7% (RSD). This developed method is suitable for separation of U and its isotope ratio measurement in environmental samples.
