时间分辨紫外脉冲荧光法测定锆矿中的铀

Determination of Uranium in Zirconium Mineral by Induced Time-resolution UV Fluorescence Method

基于前人研究工作,开展时间分辨紫外脉冲荧光法测定天然伴生放射性锆矿样品中铀含量的方法研究。与电感耦合等离子体质谱法相比,该法正确度好、精密度高、抗干扰能力强、适应性强。实验表明体系酸碱度影响荧光强度显著,但当pH值在6.85～9.10范围时,荧光强度较高且相对稳定。对31种阳离子干扰进行实验,结果表明Sn、Cr、Sb、Tl、Rh、Mn、Ag、Bi等阳离子可使荧光强度显著降低;溶液中Zr元素质量浓度低于200μg·mL^(-1)时,对荧光强度影响不明显,Zr元素质量浓度为200～500μg·mL^(-1)时,荧光强度随Zr元素质量浓度的增加而逐渐减弱。采用过氧化钠碱熔-硝酸提取天然伴生放射性锆矿样品,样品能够消解完全。采用标准加入法,用紫外脉冲荧光法测定铀含量,检出限为0.05μg·g^(-1),测定范围为0.15～4500μg·g^(-1);铀含量在40～735μg·g^(-1)时,RSD为2.1%～7.7%;铀含量为288μg·g^(-1)的锆矿样品,正确度为5.2%。

Based on previous studies,an induced time-resolution UV pulsed fluorescence method was developed to determine uranium in zirconium mineral associated Naturally Occurring Radioactive Material(NORM).Compared with the inductively coupled plasma mass spectrometry,the method has the advantages of good accuracy,high precision,strong anti-interference ability and strong adaptability.The experimental results showed that pH has significant influence on fluorescence intensity,but when pH is in the range of 6.85~9.10,the fluorescence intensity is relatively stable.The interference of 31 kinds of cation has been investigated,among which Sn,Cr,Sb,Tl,Rh,Mn,Ag,Bi can significantly reduce the fluorescence intensity.And when the concentration of Zr in solution is bellow 200μg·mL^-1,it is not obvious that the cation affect the fluorescence intensity.However,when the concentration is between 200μg·mL^-1 and 500μg·mL^-1,the fluorescence intensity will decrease with the increase of Zr concentration.Zirconium mineral samples can be digested completely by melting with sodium peroxide and nitric acid extraction.The detection limit is 0.05μg·g^-1,the range of determination is 0.15μg·g^-1~4 500μg·g^-1,the RSD is 2.1%~7.7%for uranium content in the range of 40μg·g^-1~735μg·g^-1,and the accuracy is 5.2%for zirconium ores samples with 288μg·g^-1 uranium,when the uranium content is determined by the standard addition method and UV pulsed fluorescence method.