Separation of Thorium and Uranium from Silicate Rock Samples Using Two Commercial Extraction Chromatographic Resins

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• 作者：Tetsuya Yokoyama ; Akio Makishima ; and Eizo Nakamura
• 刊名：Analytical Chemistry
• 出版年：1999
• 出版时间：January 1, 1999
• 年：1999
• 卷：71
• 期：1
• 页码：135 - 141
• 全文大小：217K
• 年卷期：v.71,no.1(January 1, 1999)
• ISSN：1520-6882

文摘

A new chemical separation technique to isolate Th and Ufrom silicate rocks was established by using two kinds ofcommercial extraction chromatographic resins. In the firstcolumn procedure, with U/TEVA·spec resin, almost allelements except Th and U were eluted by 4 M HNO₃. Thwas then separated by using 5 M HCl, and U was finallyisolated by successive addition of 0.1 M HNO₃. A significant amount of Zr still remained in the Th fraction, whichwas then further purified in the second column stageusing TEVA·spec resin. In the second procedure, Zr waseluted first by using 2 M HNO₃, and then Th was collectedby 0.1 M HNO₃. Both the Th and U fractions obtained bythese procedures were sufficiently pure for thermal ionization mass spectrometric (TIMS) analysis. Recoveryyields of Th and U exceeded 90%, and total blanks were<19 pg for Th and <10 pg for U. Our method hasadvantages over previous methods in terms of matrixeffects, tailing problems, and degree of isolation. SinceTh and U are effectively separated without suffering anymatrix interference from coexisting cations and anions,this technique can be used not only for the analysis ofigneous rock samples but also for the analysis of soils,marine sediments, carbonates, phosphates and seawater,groundwater, and surface water.