激光烧蚀-双光束二极管激光原子吸收光谱法测定固体样品中的铀同位素比  

Measurement of Uranium Isotope Ratio in Solid Sample by Laser Ablation and Double-Beam Diode Laser Atomic Absorption

作　　者：刘洪涛[1] 张展霞[1] Quentmeier A Niemax K 

机构地区：[1]中山大学化学与化学工程学院,广东广州510275 [2]Institute of Spectrochemistry and Applied Spectroscopy(ISAS)

出　　处：《光谱学与光谱分析》2004年第10期1244-1247,共4页Spectroscopy and Spectral Analysis

摘　　要：以两个二极管激光作为光源 ,采用激光烧蚀 双光束二极管激光原子吸收光谱法测定了2 3 5U/ 2 3 8U同位素比。实验对用于样品烧蚀的Nd :YAG激光聚焦点位置进行了优化 ,在同时满足一定原子化程度和较高2 3 5U 6 82 6 736nm信背比的原则下 ,选择了聚焦点位置低于样品表面 0 4cm作为分析条件。测量2 3 5U/ 2 3 8U同位素比的精密度和准确度分别为 5 %和 2 % ,2 3 5U检测限为 18μg·g-1。结果表明 ,双光束检测法能消除激光烧蚀脉冲间信号波动对测量重现性的影响 。The (235)U/(238) U isotope ratio was determined by diode laser atomic absorption spectrometry in a plasma induced by a Nd: YAG laser. Two diode lasers, which probed almost the same plasma volume, were used as light sources. (235)U and (238)U absorption signals were simultaneously measured by tuning the diode lasers to the absorption lines 682.673 6 nm and 682.076 8 nm, respectively. The optimal focus position for the Nd: YAG laser was found to be 0.4 cm below the sample surface. The precision and accuracy of (215)U/(238) U isotope ratio determination were obtained to be 5 % and 2 %, respectively. The detection limit of the (235)U isotope, evaluated on the basis of 3sigma criteria, was estimated to be 18 mug(.)g(-1). All these results show an improvement compared with the method in which only one diode laser was used as a light source.

关 键 词：激光烧蚀 双光束二极管激光 原子吸收光谱法 固体 铀 同位素比 

分 类 号：O614.62[理学—无机化学] O657.3[理学—化学]