多接收电感耦合等离子体质谱法测定岩石和土壤等国家标准物质的硅同位素组成  

Determination of Silicon Isotopic Compositions of Rock and Soil Reference Materials by MC-ICP-MS

作　　者：杨林 石震 于慧敏[1,2] 黄方[1,2] YANG Lin;SHI Zhen;YU Huimin;HUANG Fang(Key Laboratory of Crust-Mantle Materials and Environments,Chinese Academy of Sciences,School of Earth and Space Sciences,University of Science and Technology of China,Hefei 230026,China;Center for Excellence in Comparative Planetology,Chinese Academy of Sciences,University of Science and Technology of China,Hefei 230026,China)

机构地区：[1]中国科学技术大学地球和空间科学学院,中国科学院壳幔物质与环境重点实验室,安徽合肥230026 [2]中国科学院比较行星学卓越创新中心,中国科学技术大学,安徽合肥230026

出　　处：《岩矿测试》2023年第1期136-145,共10页Rock and Mineral Analysis

基　　金：中国科学院战略性先导科技专项(XDB 41000000);国家自然科学基金项目(41873007,42173003)。

摘　　要：随着分析方法的进步和分析精度的提高,硅(Si)同位素被越来越多地应用于地球化学、宇宙化学和环境化学研究中,可以用于示踪壳幔物质循环、俯冲流体的来源,以及制约月球和地外天体的起源与演化等。为确保不同类型样品中硅同位素测量的准确性和不同实验室间数据可以进行对比,需标定一系列标准物质的硅同位素组成。前人工作中已经标定一系列来自美国地质调查局(USGS)的标准物质的硅同位素,为硅同位素的研究奠定了坚实的基础。但由于这些标准物质已经售罄,今后继续开展硅同位素研究面临无标样可用的境况。为了能持续性地用高精度硅同位素数据对相关领域研究提供支持,急需对新的标准物质进行高精度的硅同位素的测量。本文采用氢氧化钠碱熔法消解样品,经化学纯化后,利用多接收电感耦合等离子体质谱法精确测量了30个国家标准物质的硅同位素组成,δ^(30)Si值测试精度优于0.08‰。这些标准物质包括11个火成岩、2个变质岩、2个沉积岩、6个河流和海洋沉积物以及9个土壤,SiO_(2)含量范围为32.69%~90.36%,覆盖了大部分自然样品的变化范围。在这些标准物质中,河流沉积物GBW07310具有最高的δ^(30)Si值,为0.85‰±0.01‰,而受高度风化作用影响的黄红色土壤GBW07405和砖红壤GBW07407具有较低的δ^(30)Si值,硅同位素组成分别为-0.68‰±0.03‰和-1.82‰±0.03‰,其余大部分标准物质的δ^(30)Si值变化范围为-0.42‰~-0.07‰。本文对这些国家标准物质硅同位素组成的精确标定,丰富了硅同位素研究的标准样品数据库,为全球不同实验室的硅同位素测试提供了基础数据,为后续在多种领域开展硅同位素研究打下坚实的基础。BACKGROUND:With the analytical technique development,the precision of Si isotopes analysis increases rapidly.Silicon isotopes are widely used in geochemistry,cosmochemistry,environmental chemistry and so on,and can be used to trace the circulation of crust-mantle material,the source of subducting fluid,and constrain the origin and evolution of the moon and extraterrestrial materials.To compare the precision and accuracy of Si isotope analysis results in different laboratories,it is necessary to analyze Si isotopes of reference materials with published Si isotope data.As generally used USGS reference materials are currently unavailable,it is important to report Si isotopes of new reference materials.OBJECTIVES:In order to continuously conduct research in various fields with high-precision silicon isotope data,by providing a supply of new reference materials.Silicon isotopes of 30 GBW reference materials with different compositions,including 11 igneous rocks,2 sedimentary rocks,2 metamorphic rocks,6 river/marine sediments and 9 soils,were analyzed.The SiO_(2)content of these reference materials ranged from 32.69%to 90.36%,covering the variation range of most natural samples.METHODS:Alkali fusion method was used for sample digestion.Approximately 3-5mg of sample powder and 200mg of powdery NaOH were weighed in a 10mL silver crucible and heated.The Si purification was obtained using cation exchange resin AG50W-X12.6mol/L HNO3and ultrapure water were used to clean the resin before sample loading.Silicon isotopes were measured by multi-collector inductively coupled plasma-mass spectrometry(MC-ICP-MS,Neptune Plus)at the laboratory in the University of Science and Technology of China(USTC),and the instrument mass bias was corrected by standard-sample-standard method,with a bracketing standard of NBS-28.The long-term reproducibility(over two years)of Si isotope analysis of one in-house standard(USTC-Si)and one international rock reference material(BHVO-2)were represented,with theδ^(30)Si values of USTC-Si and BHVO-2 of-0

关 键 词：硅同位素 国家标准物质 碱熔法 多接收电感耦合等离子体质谱法 高精度测试方法 

分 类 号：O657.63[理学—分析化学]