细菌反硝化法测定10^-6级硝酸盐的氮和三氧同位素  

Measurements of Nitrogen and Triple Oxygen Isotope Composition of Nitrate at 10^-6 Level by the Denitrifier Method

作　　者：范昌福[1] 曲冬梅[2] 秦燕[1] 胡斌[1] 高建飞[1] 武晓珮 李延河[1] FAN Chang-fu;QU Dong-mei;QIN Yan;HU Bin;GAO Jian-fei;WU Xiao-pei;LI Yan-he(MNR Key Laboratory of Metallogeny and Mineral Assessment,MNR Key Laboratory of Isotope Geology,Institute of Mineral Resources,Chinese Academy of Geological Sciences,Beijing 100037;Institute of Tibetan Plateau Research,Chinese Academy of Sciences,Beijing 100101)

机构地区：[1]中国地质科学院矿产资源研究所,自然资源部成矿作用与资源评价重点实验室,自然资源部同位素地质重点实验室,北京100037 [2]中国科学院青藏高原研究所,北京100101

出　　处：《地球学报》2020年第5期591-604,共14页Acta Geoscientica Sinica

基　　金：国家自然科学基金项目(编号:41473013,41627802)资助。

摘　　要：硝酸盐的氮和三氧同位素(δ^15N,δ^17O和δ^18O)及氧同位素非质量分馏(△^17O)综合研究,可以更有效地示踪硝酸盐的来源和形成过程、制约硝酸盐的形成条件。本文详细描述了细菌反硝化法测定10^-6级硝酸盐氮和三氧同位素的分析测试方法和实验要点。综合优化改良的细菌反硝化前处理方法、全自动气体预浓缩富集纯化系统和测试流程,实现了实验室长期测定数据的稳定性,以及多批次标准样品测定的良好重现性。10 nmol NO3^-标准样品的δ^18O和δ15N测试精度分别是0.25‰(1σ)和0.40‰(1σ)。80 nmol NO3^-标准样品的δ^18O、δ^17O和δ15N的测试精度分别是0.5‰(1σ)、0.4‰(1σ)和0.1‰(1σ),据此计算出的Δ^17O精度为0.46‰(1σ)。The comprehensive study of nitrate nitrogen and trioxygen isotopes(δ^15N,δ^17O and δ^18O)and mass independent fractionation(Δ^17O)can more effectively trace the source and transformation processes of nitrate and restrict the formation conditions of nitrate.This paper describes in detail the analytical protocols and same key points for the analysis of ppm nitrate δ^15N,δ^17O and δ^18O by the denitrifier method.Comprehensive optimization of the improved bacterial denitrification pretreatment method and fully automatic gas pre-concentration enrichment and purification system together with analyzing process have achieved long-term stability between two laboratories and good reproducibility of multiple batches of reference samples.The external precision ofδ18O andδ15N of 10 nmol NO3^- reference samples are 0.25‰(1σ)and 0.40‰(1σ)respectively.The external precision of δ^18O,δ^17O and δ^15N of the 80 nmol NO3^- reference samples are 0.5‰(1σ),0.4‰(1σ)and 0.1‰(1σ)respectively.In addition,the calculated external precision of Δ^17O of the 80 nmol NO3^- reference samples is 0.46‰(1σ).

关 键 词：反硝化细菌法 硝酸盐 氮同位素 三氧同位素 

分 类 号：P597.2[天文地球—地球化学]