负离子热表面电离质谱法测量铼的化学分离方法研究  

Method Study on the Separation and Enrichment of Rhenium Measured by Negative Thermal Ionization Mass Spectrometry

作　　者：王礼兵[1] 屈文俊[1] 李超[1] 周利敏[1] 杜安道[1] 俎波[2] 

机构地区：[1]中国地质科学院Re-Os同位素地球化学重点实验室,国家地质实验测试中心,北京100037 [2]中国地质大学(北京)地球科学与资源学院,北京100083

出　　处：《岩矿测试》2013年第3期402-408,共7页Rock and Mineral Analysis

基　　金：国家自然科学基金项目(41203037)

摘　　要：Re-Os同位素定年中,丙酮萃取法分离Re比传统的阴离子交换法流程简单快速。用本实验室原有丙酮萃取流程纯化的Re溶液可用电感耦合等离子体质谱(ICP-MS)测定,但由于盐量较高(>1 mg/mL)不能直接用于负离子热表面电离质谱(N-TIMS)测定。本文对Re-Os同位素定年方法中原有丙酮萃取分离Re的流程进行改进,将丙酮萃取和碱洗时的氢氧化钠浓度由5 mol/L提高到10 mol/L,有效降低了萃取后的Re溶液中的盐量,由此分离纯化的Re溶液经硝酸和过氧化氢处理,可直接点带用于N-TIMS测定。与阴离子交换分离Re方法相比,改进的丙酮萃取方法操作简单,缩减实验时间,同时有效降低全流程空白至3～7 pg,并且1 ng的Re测量信号可达到100 mV以上。经国家一级标准物质(GBW 04436)和实验室铜镍硫化物监控样品(JCBY)验证,利用改进的方法纯化,Re的测定值分别为(17.17±0.50)μg/g和(38.34±0.44)ng/g,与推荐值(17.39±0.32)μg/g和(38.61±0.86)ng/g在不确定度范围内完全吻合。目前改进的丙酮萃取方法已经应用于实际样品分析,并取得了长期稳定的良好效果。In Re-Os isotope chronology, the acetone extraction process is quicker and easier compared to the anion exchange method. The Re solution which was separated and purified by acetone extraction is suitable for the measurement by Inductively Coupled Plasma-Mass Spectrometry （ICP-MS） , but unsuitable for Negative Thermal Ionization Mass Spectrometry （N-TIMS） directly because of high salt contents. An improvement was made to the acetone extraction method to separate and purify Re for N-TIMS determination by increasing the alkalinity concentration from 5 mol/L to 10 mol/L. Compared with the anion exchange method, the acetone extraction process is not only easier to operate with lower blank （Re 3 -7 pg）, but also saves time. The signal intensity of Re was over 100 mV per 1 ng Re, which met the requirements of a high-accuracy instrument measurement completely. The national first grade standard material of JDC （ GBW 04436 ） and the laboratory reference material of JCBY were measured to verify the improved method. The Re contents of JDC and JCBY obtained from this method were （ 17.17 ±0.50） μg/g and （38.34 ± 0.44） ng/g, respectively, which were consistent with the certified value of JDC （17.39 ±0.32） p,g,/g and the certified value of JCBY （38.61±0.86） ng/g. The improved procedure was applied to practical samples with good long-term results.

关 键 词：铼-锇同位素 丙酮萃取 离子交换 负离子热表面电离质谱法 

分 类 号：O614.713[理学—无机化学] O614.826[理学—化学]