碳酸钠浸取一紫外荧光光谱法测定地质样品中痕量铀

Sodium Carbonate Solution Leaching Separation-Ultraviolet Fluorescence Spectrometric Determination of Trace Uranium in Geological Samples

地质样品经HF-HNO_3-HCl-HClO_4溶解后,用50 g/L碳酸钠溶液浸取分离,采用紫外荧光光谱法直接测定上清液的铀含量。浸取时间选择30 min,Fe、Zn、Ca、Co、Ni、Cu和Mn等元素留在残渣中不产生干扰。方法精密度(RSD,n=12)为3．37%～7．06%,检出限为0．009μg/g(进样量100μL)。方法参加区域地球化学考核样品的测试,合格率100%,适用于土壤、水系沉积物、岩石及Fe、Zn、Ca、Co、Ni、Cu和Mn含量较高的样品中痕量铀的测定。

After sample dissolution with mixed acid of HF-HNO3-HCl-HClO4, 50 g/L sodium carbonate solution was used for separation of coexistent elements with separation time of 30 min. Fe, Zn, Ca, Co, Ni, Cu and Mn remained in the residue without any interference on determination of trace uranium by ultraviolet fluorescence spectrometry. The detection limit of the method for uranium is 0.009 μg/g and precision is 3.37% -7.06% RSD （n = 12）. The method has been applied to the determination of trace uranium in geochemical samples with satisfactory results and is applicable to the determination of trace uranium in soil, stream sediment and rock samples with higher contents of Fe, Zn, Ca, Co, Ni, Cu and Mn.