锌同位素MC-ICPMS分析与加压快速分离方法的研发及地质应用

发布时间：2018-03-11 22:13

  本文选题：多接收等离子体质谱　切入点：锌同位素　出处：《西北大学》2017年硕士论文　论文类型：学位论文

【摘要】：由于锌在成矿作用,生命活动,现代工业等方面的多种应用,研究锌同位素组成具有重要意义。而锌同位素分析方法没有确定公认的参考标准极大的影响了各实验室数据的相互对比及其他实际样品的分析测试。由于多接收等离子体质谱分析速度快,灵敏度高,因而在同位素分析上得到了广泛的应用,但该方法对样品的前处理要求严格,而样品分离纯化的时间长,效率低,制约了分析方法的应用,因此提高样品前处理效率已成为迫切需求。本文研究了多接收等离子体质谱对锌同位素的高精度分析测试方法,同时开发了同位素快速分离方法,并以铜、锶、钕同位素分离方法为例验证其可靠性。主要研究内容包括以下几点:1.确定锌同位素样品溶解、分离方法以及分析测试方法。采用AG1-X8强碱性阴离子交换树脂进行分离,该分离流程相对较短,能够减少本底的引入,回收率达到99.33%。利用MC-ICP-MS对锌同位素进行分析测试,优化仪器参数,分析了不同进样方式对分析结果的影响,实验证实利用膜去溶装置的干法进样更具有优势,得到的分析结果精度更高,同时样品用量更少,有利于较低含量的锌同位素分析。对测试中可能产生的浓度效应与酸度效应进行了分析,发现对于锌同位素测试,浓度效应与酸度效应影响都较大,在进行锌同位素组成分析时需进行匹配。初步探讨了锌对铜同位素分析结果的影响,具体包括锌浓度对测试值的影响,锌对铜同位素分析时的浓度效应和酸度效应影响。2.初步研究了 NIST SRM 682作为标准样品对NIST SRM 683的长期稳定值,所得结果为δ66Zn=0.12±0.03%‰,与前人测试结果一致,同时分析了 CAGS-Zn相对于NISTSRM 682的值,并经计算转化为参考标准为JMCZn的值,结果为δ66ZZn=-0.75±0.09%‰,与报道一致,证明以SRM682为实验室内部标准是可行的。3.开发了快速分离方法,通过通入气体的方式达到提高分离效率的目的。以铜同位素为例研究了不同气体流量对分离的影响,确定了 20mL/min流量作为合适的气流条件,该条件下回收率达到99.95%,同时将分离时间缩短为原来的50%,极大的提高了分离效率。对该条件下对不同分离阶段的影响做了实验探究,证明了在清洗和平衡树脂阶段使用该方法能够在保证分析结果正确的情况下提高分离效率。4.将快速分离方法应用于Sr,Nd同位素的分离上,通过对不同分离阶段下通入气体对Sr,Nd分离的影响研究,得出了加速分离方法同样适用于Sr,Nd样品的分离过程。一次分离时将分离效率提高2倍,二次分离时则使分离效率提高1.2倍。
[Abstract]:Due to the various applications of zinc in mineralization, life activities and modern industry, It is of great significance to study the composition of zinc isotopes. However, the failure of zinc isotope analysis methods to determine the accepted reference standards greatly affects the comparison of laboratory data and the analysis and testing of other actual samples. The analysis speed of plasma mass spectrometry is fast, Because of its high sensitivity, this method has been widely used in isotope analysis. However, the method requires strict pretreatment of samples, and the separation and purification time of samples is long and the efficiency is low, which restricts the application of the analytical method. Therefore, it has become an urgent need to improve the pretreatment efficiency of samples. In this paper, a high precision analytical method for the determination of zinc isotopes by multi-receiving plasma mass spectrometry has been studied, and a rapid isotope separation method has been developed, and copper and strontium have been used for the determination of zinc isotopes. The method of neodymium isotope separation is used as an example to verify its reliability. The main research contents are as follows: 1. To determine the dissolution of zinc isotopic sample, separation method and analytical test method. AG1-X8 strong basic anion exchange resin is used for separation. The separation process is relatively short and can reduce the introduction of background, and the recovery rate is 99.33. The zinc isotope is analyzed and tested by MC-ICP-MS, the parameters of the instrument are optimized, and the influence of different sampling methods on the analysis results is analyzed. The experimental results show that the dry sample injection with membrane stripping device has more advantages, the accuracy of the analysis results is higher, and the amount of sample is less. The concentration effect and acidity effect of zinc isotopic test are analyzed, and it is found that the concentration effect and acidity effect are significant for zinc isotope test. The effect of zinc on the results of copper isotopic analysis was preliminarily discussed, including the effect of zinc concentration on the measured values. The effect of zinc on the concentration and acidity of copper isotopic analysis. 2. The long-term stable value of NIST SRM 682 for NIST SRM 683 was studied. The result is 0. 12 卤0.03% 鈥，

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