微量水δ(^(17)O)和δ(^(18)O)CoF_3法线外同时测试新技术  

A New Technique for the Determination of ^(18)O/^(16)O and ^(17)O/^(16)O Isotopic Ratios in Micro-liter Water

作　　者：余婷婷[1,2] 甘义群[1,2] 刘存富[1,2] 李小倩[1,2] 刘运德[1,2] 蔡鹤生[1,2] 周爱国[1,2] 周建伟[1,2] 

机构地区：[1]中国地质大学环境学院,武汉430074 [2]中国地质大学生物地质与环境地质教育部重点实验室,武汉430074

出　　处：《地质科技情报》2010年第1期121-125,共5页Geological Science and Technology Information

基　　金：国家自然科学基金项目(40602030)

摘　　要：三氧同位素(16O、17O、18O)组成特征可有效示踪天然水循环及其环境效应,微量水δ(17O)和δ(18O)CoF3法同时测试新技术的建立,可为三氧同位素定量研究提供有效的分析手段,特别是能够捕捉到像光合作用、呼吸作用等生物过程中发生的同位素分馏现象。在国内首次建立了微量水δ(17O)和δ(18O)CoF3法线外同时测试新技术,样品量仅需2μL,整个制样时间约40min。采用在质谱测试前对待测样品在100℃下预热10 min,待O2完全解吸后再进行质谱测试的方法,避免了制样和测试过程中的记忆效应及分馏效应,δ(17O)和δ(18O)的分析精度分别达到±0.07‰和±0.14‰。该法使用固体试剂CoF3替代了剧毒的气态氟化物BrF5,使得制样流程更加安全可靠且样品量少,适用性强,具有很大的推广应用价值。Tri-oxygen isotopes（^16O、^17O、^18O） composition in water is a very effective tool to trace the origin and formation environment of water, and tri-oxygen isotopic studies have become a hot and fore front topic with the development of mass-independent isotopic fractionation. This study has set up a new technique for the determination of ^18O/^16O and ^17O/^16O isotopic ratios in water from small liquid sample for the first time in China. The new technique will enlarge isotopic research field, such as quantitative determination of oxygen isotopic fractionation in the biological process of photosynthesis and respiration. The method of water fluorination is optimized by using the solid reagent CoF3 to produce O2. This allows the isotope ratio measurements by dual-inlet mass spectrometry with very high precision of ±0.07‰ and ±0.14‰ for both δ^17O and δ^18O with water sample of only 2 μL. The fluorination step takes less than 20 min, while the total processing time of each sample is about 40 min. The method does not use the fluorination reagent BrFs employed in traditional methods. It is hence safer, cheaper and more reliable than traditional means and accords with the environmental awareness and the people-oriented principle.

关 键 词：微量水 三氧同位素(16O、17O、18O) CoF3法 非质量相关分馏 

分 类 号：P597[天文地球—地球化学]