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铀、钍在地壳中的含量平均约3ppm至8ppm。地球化学探矿样品一般要求测定低于地壳平均值的含量,如1—2ppm的铀或钍。在一次分离的溶液中测定两个痕量元素是最可取的。 Pollock在抗坏血酸存在下以硼酸掩蔽氟,用TOPO(三辛基氧膦)的环已烷溶液一次萃取铀和钍;由于要分取萃出液测定,故不能充分降低检出限。陈文华等先用氟掩蔽钍TOPC萃取铀,再用铝掩蔽氟连续萃取钍,虽弥补了上文之不足,但需两次萃取。本文采取一次萃取铀、钍,然后用0.8％氟化铵的2N硝酸溶液反萃取钍,分别在有机
Uranium, thorium in the crust average about 3ppm to 8ppm. Geochemical prospecting samples generally require determination of levels below the crustal average, such as 1-2 ppm of uranium or thorium. Determining two trace elements in a single solution is the most desirable. Pollock masks fluorine with boric acid in the presence of ascorbic acid and extracts the uranium and thorium in a single step with TOPO (trioctylphosphine oxide) in cyclohexane; the limit of detection can not be sufficiently reduced due to the fractional extraction of the extract. Chen Wenhua and other first thorium TOPC fluoride extraction uranium, aluminum and then covered with fluorine continuous extraction of thorium, although to make up for the above deficiencies, but two extractions. In this paper, once extracted uranium, thorium, and then with 0.8% ammonium fluoride 2N nitric acid solution stripping thorium, respectively, in the organic