论文部分内容阅读
本文开发了一种新的高效液相色谱(HPLC)法,并应用于地质材料中U和Th含量的测定。首先用HF-HClO_4和HCl浸提液在螺旋盖Savillex烧杯中酸消解岩石样品,然后Th和U用定量的两步离子交换法从地质基体中分离出来,最后采用HPLC进行元素测定。Th和U在反相交换柱上用梯度淋洗,10min即互相分离,而且剩余基体元素以α-羟基异丁酸(HIBA)络合物形式与Th和U分离。在与偶氮胂Ⅲ在线后置柱反应之后,Th和U的测定是用可见分光光度测定法完成的。Th和U的检测限分别约为30×10~(-12)和100x10~(12)(或约0.75×10~(-9)和约2.5×10~(-9),用100mg岩石样品)。 HPLC技术已应用于评价分析特性的9种国际参考样品和3种性能良好的管理样品分析。分析样品中Th和U的浓度范围为<10×10~(-9)～>10×10~(-6),HPLC数据与火花源质谱、电感耦合等离子体(ICP)和同位素稀释热电离质谱分折的数值完全吻合。对Th和U含量分别高于50×10~(-9)和5×10~(-9)的测量,方法精密度在1σ置信水平时分别好于±2％和±5％。
In this paper, a new high performance liquid chromatography (HPLC) method was developed and applied to the determination of U and Th in geological materials. Rock samples were first acid-digested with HF-HClO 4 and HCl extracts in a screw-cap Savillex beaker, and then Th and U were separated from the geological matrix using a quantitative two-step ion exchange method. Finally, the elemental determinations were performed by HPLC. Th and U were eluted with a gradient on reversed phase exchange columns, separated from each other for 10 min, and the remaining matrix elements were separated from Th and U as alpha-hydroxyisobutyric acid (HIBA) complexes. After an on-line postcolumn reaction with arsenazo III, the determination of Th and U was done using visible spectrophotometry. The detection limits for Th and U are about 30 × 10 ~ (-12) and 100 × 10 ~ (12) (or about 0.75 × 10 -9 and about 2.5 × 10 -9, respectively, with 100 mg rock samples). HPLC technology has been applied to evaluate 9 analytical properties of the international reference sample and 3 well-managed sample analysis. The concentrations of Th and U in the analysis samples ranged from 10 × 10 -9 to 10 × 10 -6. HPLC data were compared with spark source mass spectrometry, inductively coupled plasma (ICP) and isotope dilution thermal ionization mass spectrometry Fraction of the value exactly. For the measurement of Th and U contents higher than 50 × 10 -9 and 5 × 10 -9 respectively, the precision of the method was better than ± 2% and ± 5% at 1σ confidence level respectively.