摘要:
对3个土壤样和2个放射性河床沉积物的国家标准物质进行了微波消解,又采用TOPO萃取和液体荧光法分析了样品中的铀含量,并将分析结果与国家标准方法GB11220 2—89的分析结果进行了比较。结果表明,微波消解法与国家标准方法一样,均不能实现土壤的全部消解,但与国家标准方法相比较,微波消解速度快,所需试剂量少,且易于实现定量控制,铀回收率高,分析精度高。对不溶物进行X射线能谱分析发现,其主要组成为铝、钛及过渡金属的氟化物或氧化物。同位素质谱分析表明,国家标准物质GBW08304中的234U,235U均比天然丰度低,另一个国家标准物质GBW08304a中铀的同位素分布与天然组成基本一致。
关键词:
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土壤
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微波消解
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铀
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浓度
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同位素丰度
Abstract:
Three soil samples and two radioactive river sediments are digested by microwave. Uranium in samples is extracted by TOPO and determined by liquid fluorimetry.The uranium isotope distribution in the two radioactive samples is measured by HP-ICP-MS. Compared with Chinese standard method GB11220.2-89, the procedure tried in this work is faster with less reagents. The recovery of uranium is higher and the precision of determination is also better. The determined abundance of)~234)U and)~235)U in GBW08304a is almost as same as the natural uranium. While the lighter isotopes of uranium in GBW08304 are somewhat depleted. The undigestable part of soil sample GBW-07404-GSS-4, explored by scanning electron microscope with EDS, is found to be composed of F,O,Al,Cu,Ti,etc.
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