| 高反应温度对五氟化溴法氧同位素组成测定的影响 |
| |
| 引用本文： | 张建锋,刘汉彬,石晓,金贵善,韩娟,李军杰,张佳,郭东侨.高反应温度对五氟化溴法氧同位素组成测定的影响[J].地球科学,2021,46(12):4470-4479. |
| |
| 作者姓名： | 张建锋 刘汉彬 石晓 金贵善 韩娟 李军杰 张佳 郭东侨 |
| |
| 作者单位： | 核工业北京地质研究院,北京 100029 |
| |
| 基金项目： | 国家重点研发计划项目“华南热液型铀矿基地深部探测技术示范”2017YFC0602600核工业北京地质研究院院长青年科技创新基金项目测QJ2008 |
| |
| 摘 要： | 五氟化溴法在分析氧化物和硅酸盐矿物的氧同位素组成时，反应温度与反应时间是关键要素.在保证反应时间的前提下，研究较高反应温度条件（550~800 ℃）对五氟化溴法氧同位素组成分析的影响.在高反应温度条件下对国家标准物质GBW04409进行氧同位素样品制备与同位素组成分析表明:反应温度在550~675 ℃，获得了较足量的O2产率，δ18O集中在10.4‰~11.8‰范围，准确度较高；反应温度高于700 ℃后，O2产率降低，δ18O分布在10.8‰~26.8‰范围，δ18O产生明显的正偏差；通过分次氟化反应、合并收集气体的方式获得了与标准物质推荐值相吻合的δ18O分析结果.在高于700 ℃的反应温度条件下，BrF5与镍反应器发生反应，增加了试剂消耗.由于BrF5试剂量不足，导致O2产率偏低从而引起氧同位素分馏.
|
| 关 键 词： | 氧同位素组成 五氟化溴法 反应温度 产率 地球化学 |
| 收稿时间： | 2021-01-12 |
High Reaction Temperature Influence on Determination of Oxygen Isotopic Composition by BrF5 Method |
| |
| Abstract: | Reaction temperature and reaction time are key factors for the determination of oxygen isotopic composition of oxides and silicate minerals by BrF5 method. This work aims to study the effect of the higher temperature (550-800℃) on the oxygen isotopic composition analysis by BrF5 method. The national standard sample GBW04409 for oxygen isotopic composition were prepared and analyzed at high reaction temperatures. The results show that sufficient yields of O2 could be achieved when sample was reacted with BrF5 at 550-675℃, under which condition the δ18O value fell in the range of 10.4‰-11.8‰ with high accuracy. However, when the reaction temperature was higher than 700℃, the yields of O2 were low, and the δ18O values were in the range of 10.8‰-26.8‰, which had a significant positive deviation to the given δ18O values. To solve the problem due to effect of the higher temperature, fractional fluorination was conducted. The results of oxygen isotopic composition obtained were consistent with the recommended value when the oxygen liberated after each time fluorination was all collected. The consumption of BrF5 by the nickel reactor at higher temperature results in the insufficient amount of BrF5 reacted with the sample, which causes the low yield of O2, thus the fractionation of oxygen isotope. |
| |
| Keywords: | |
| 本文献已被 万方数据 等数据库收录！ |
| 点击此处可从《地球科学》浏览原始摘要信息 |
| 点击此处可从《地球科学》下载免费的PDF全文 |
|
