微波消解-多接收电感耦合等离子体质谱高精度测定锶钕同位素组成
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摘要
应用多接收器电感耦合等离子体质谱仪(MC-ICP-MS)测定地质样品中锶、钕同位素组成时,化学前处理流程冗长、复杂,且容易出现样品未完全溶解的现象。本文采用微波消解法消解样品,在保证消解效果的前提下有效地缩短了溶样时间,在此基础上研究了锶、钕化学分离和质谱测试流程,重点考察了树脂柱的回收率和记忆效应。结果表明:树脂经10次使用后的锶、钕流程空白均低于1.0 ng,但回收率明显下降,分别由原来的98%和90%降到20%和50%,若待测样品中锶、钕含量较低,所接收的锶、钕则达不到质谱仪测试范围,因此建议锶特效树脂使用次数不超过5次,AG50W-X8稀土柱和Ln树脂使用次数不超过10次。整套流程应用于国际地质标准样品(BCR-2、W-2a、BHVO-2、AGV-2)的锶、钕分离,MC-ICP-MS所得的87Sr/86Sr、143Nd/144Nd测定值与文献报道值一致,仪器的内精度2SE(n=50)和方法的外精度2SD(n=6)均优于0.0015%,表明该流程可以满足地质样品中锶、钕同位素高精度测定的要求。
BACKGROUND: Determination of strontium( Sr) and neodymium( Nd) isotopic composition in geological samples by Multi-collector Inductively Coupled Plasma-Mass Spectrometry( MC-ICP-MS) needs a lengthy and complex chemical preparation procedure. Moreover,samples cannot be dissolved completely.OBJECTIVES: To effectively digest samples and eliminate interferences from the experimental process.METHODS: Geological samples were dissolved by microwave digestion. The processes of Sr,Nd chemical separation and mass spectrometry analyses were studied. In particular,the recovery and memory effect of resin column were investigated.RESULTS: The research shows that after ten times usages Sr and Nd procedure,blanks of the resin are less than1. 0 ng. However,the recovery decreases significantly from 98% to 20% and 90% to 50%,respectively. If the analyzed samples contain low concentrations of Sr and Nd,which are insufficient for mass spectrometry analysis,it is suggested that Sr special effect resin should be used no more than 5 times and AG50 W-X8 and Ln resin should be used no more than 10 times. The entire procedure is applied in the separation of Sr and Nd of international standard geological samples( BCR-2,W-2 a,BHVO-2,AGV-2). The acquired87 Sr/86 Sr and143 Nd/144 Nd ratios are consistent with those in the literature,and the instrumental internal precision 2 SE( n = 50) and methodological external precision 2 SD( n = 6) are better than 0. 0015%.CONCLUSIONS: The proposed method meets the requirement of high-precision measurement of Sr and Nd isotopic composition in geological samples.
BACKGROUND: Determination of strontium( Sr) and neodymium( Nd) isotopic composition in geological samples by Multi-collector Inductively Coupled Plasma-Mass Spectrometry( MC-ICP-MS) needs a lengthy and complex chemical preparation procedure. Moreover,samples cannot be dissolved completely.OBJECTIVES: To effectively digest samples and eliminate interferences from the experimental process.METHODS: Geological samples were dissolved by microwave digestion. The processes of Sr,Nd chemical separation and mass spectrometry analyses were studied. In particular,the recovery and memory effect of resin column were investigated.RESULTS: The research shows that after ten times usages Sr and Nd procedure,blanks of the resin are less than1. 0 ng. However,the recovery decreases significantly from 98% to 20% and 90% to 50%,respectively. If the analyzed samples contain low concentrations of Sr and Nd,which are insufficient for mass spectrometry analysis,it is suggested that Sr special effect resin should be used no more than 5 times and AG50 W-X8 and Ln resin should be used no more than 10 times. The entire procedure is applied in the separation of Sr and Nd of international standard geological samples( BCR-2,W-2 a,BHVO-2,AGV-2). The acquired87 Sr/86 Sr and143 Nd/144 Nd ratios are consistent with those in the literature,and the instrumental internal precision 2 SE( n = 50) and methodological external precision 2 SD( n = 6) are better than 0. 0015%.CONCLUSIONS: The proposed method meets the requirement of high-precision measurement of Sr and Nd isotopic composition in geological samples.
引文
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[12]Liu H C,Chung C H,You C F,et al.Determination of87Sr/86Sr andδ88Sr/86Sr ratios in plant materials using MC-ICP-MS[J].Analytical and Bioanalytical Chemistry,2016,408:387-397.
[13]宗春蕾,袁洪林,戴梦宁.一次溶样分离地质样品中Pb-Sr-Nd方法的可行性研究[J].岩矿测试,2012,31(6):945-949.Zong C L,Yuan H L,Dai M N.A feasibility study on chemical separation of Pb,Sr and Nd from the same single dissolution of geological sample[J].Rock and Mineral Analysis,2012,31(6):945-949.
[14]苟龙飞,金章东,邓丽,等.高效分离Li及其同位素的MC-ICP-MS精确测定[J].地球化学,2017,46(6):528-537.Gou L F,Jin Z D,Deng L,et al.Efficient purification for Li and high-precision and accuracy determination of Li isotopic compositions by MC-ICP-MS[J].Geochemical,2017,46(6):528-537.
[15]de Carvalho G G A,Oliveira P V,Yang L.Determination of europium isotope ratios in natural waters by MC-ICPMS[J].Journal of Analytical Atomic Spectrometry,2017,32:987-995.
[16]Dominique W,Bruno K,Claude M,et al.High-precision isotopic characterization of USGS reference materials by TIMS and MC-ICP-MS[J].Geochemistry,Geophysics,Geosystems,2006,7(8):1-30.
[17]袁永海,元志红.微波消解-磷钼蓝分光光度法测定钨矿石中的磷含量[J].中国无机分析化学,2015,5(1):24-27.Yuan Y H,Yuan Z H.Determination of phosphorus in tungsten ores by microwave digestion-phosphorus molybdenum blue spectrophotometry[J].Chinese Journal of Inorganic Analytical Chemistry,2015,5(1):24-27.
[18]袁永海,尹昌慧,元志红,等.氢化物发生-原子荧光光谱法同时测定锡矿石中的砷和锑[J].冶金分析,2016,36(3):39-43.Yuan Y H,Yin C H,Yuan Z H,et al.Determination of arsenic and antimony in tin ore by hydride generationatomic fluorescence spectrometry[J].Metallurgical Analysis,2016,36(3):39-43.
[19]黎卫亮,程秀花,李忠煜,等.碱熔共沉淀-电感耦合等离子体质谱法测定橄榄岩中的稀土元素[J].岩矿测试,2017,36(5):468-473.Li W L,Cheng X H,Li Z Y,et al.Determination of rare earth elements in peridotite by inductively coupled plasma-mass spectrometry after alkali fusion and Mg(OH)2and Fe(OH)3coprecipitation[J].Rock and Mineral Analysis,2017,36(5):468-473.
[20]李潮峰,李献华,郭敬辉,等.微量岩石样品中Rb-Sr和Pb一步分离及高精度热电离质谱测试[J].地球化学,2011,40(5):399-406.Li C F,Li X H,Guo J H,et al.Single-step separation of Rb-Sr and Pb from minor rock samples and high precision determination using thermal ionization mass spectrometry[J].Geochemical,2011,40(5):399-406.
[2]Deng K,Li Q G,Chen Y J,et al.Geochronology,geochemistry and Sr-Nd-Pb-Hf isotopes of the Early Jurassic granodiorite from the Sankuanggou intrusion,Heilongjiang Province,Northeastern China:Petrogenesis and geodynamic implications[J].Lithos,2018,296-299:113-128.
[3]刘贤荣,林晓辉,于瑞莲,等.铅-锶-钕同位素示踪技术在PM2.5源解析中的应用[J].环境科学导刊,2016,35(5):55-59.Liu X R,Lin X H,Yu R L,et al.Application of Pb-Sr-Nd isotopic tracing technique in the recognition and analysis of PM2.5pollution sources[J].Environmental Science Survey,2016,35(5):55-59.
[4]邵磊,李长安,张玉芬,等.长江上游水系沉积物锶-钕同位素组成及物源示踪[J].沉积学报,2014,32(2):290-295.Shao L,Li C A,Zhang Y F,et al.Sr-Nd isotopic compositions of the upper Yangtze River sediments:Implications for tracing sediment sources[J].Acta Sedimentologica Sinca,2014,32(2):290-295.
[5]刘家军,吕志成,吴胜华,等.南秦岭大巴山大型钡成矿带中锶同位素组成及其成因意义[J].地学前缘,2014,21(5):23-30.Liu J J,LüZ C,Wu S H,et al.Strontium isotopic composition and its genetic significance of the Dabashan large barium metallogenic belt in Southern Qingling mountains[J].Earth Science Frontiers,2014,21(5):23-30.
[6]蔡伊,张乾,张永斌,等.桂中镇圩碳酸盐岩型滑石矿床热液方解石的锶同位素研究[J].地球化学,2015,44(5):427-437.Cai Y,Zhang Q,Zhang Y B,et al.Strontium isotopic geochemistry of hydrothermal calcites in carbonate-hosted talc deposits at Zhengxu in central Guangxi Province,South China[J].Geochemical,2015,44(5):427-437.
[7]侯可军,秦燕,李延河,等.磷灰石Sr-Nd同位素的激光剥蚀-多接收器电感耦合等离子体质谱微区分析[J].岩矿测试,2013,32(4):547-554.Hou K J,Qin Y,Li Y H,et al.In situ Sr-Nd isotopic measurement of apatite using laser ablation multi-collector inductively coupled plasma-mass spectrometry[J].Rock and Mineral Analysis,2013,32(4):547-554.
[8]Bao Z A,Yuan H L,Zong C L,et al.Simultaneous determination of trace elements and lead isotopes in fused silicate rock powders using a boron nitride vessel and fs LA-(MC)-ICP-MS[J].Journal of Analytical Atomic Spectrometry,2016,31:1012-1022.
[9]李杨,杨岳衡,焦淑娟,等.金红石Hf同位素激光原位多接收等离子体质谱(LA-MC-ICP-MS)测定[J].中国科学(地球科学),2016,46(6):857-869.Li Y,Yang Y H,Jiao S J,et al.In situ determination of hafnium isotopes from rutile using LA-MC-ICP-MS[J].Science China(Earth Sciences),2015,58:2134-2144.
[10]何连花,刘季花,张俊,等.MC-ICP-MS测定富钴结壳中的铜锌同位素的化学分离方法研究[J].分析测试学报,2016,35(10):1347-1350.He L H,Liu J H,Zhang J,et al.Separation of Cu and Zn in cobalt-rich crusts for isotope determination by MCICP-MS[J].Journal of Instrumental Analysis,2016,35(10):1347-1350.
[11]Li C F,Li X H,Li Q L,et al.Rapid and precise determination of Sr and Nd isotopic ratios in geological samples from the same filament loading by thermal ionization mass spectrometry employing a single-step separation scheme[J].Analytical Chemical Acta,2012,727:54-60.
[12]Liu H C,Chung C H,You C F,et al.Determination of87Sr/86Sr andδ88Sr/86Sr ratios in plant materials using MC-ICP-MS[J].Analytical and Bioanalytical Chemistry,2016,408:387-397.
[13]宗春蕾,袁洪林,戴梦宁.一次溶样分离地质样品中Pb-Sr-Nd方法的可行性研究[J].岩矿测试,2012,31(6):945-949.Zong C L,Yuan H L,Dai M N.A feasibility study on chemical separation of Pb,Sr and Nd from the same single dissolution of geological sample[J].Rock and Mineral Analysis,2012,31(6):945-949.
[14]苟龙飞,金章东,邓丽,等.高效分离Li及其同位素的MC-ICP-MS精确测定[J].地球化学,2017,46(6):528-537.Gou L F,Jin Z D,Deng L,et al.Efficient purification for Li and high-precision and accuracy determination of Li isotopic compositions by MC-ICP-MS[J].Geochemical,2017,46(6):528-537.
[15]de Carvalho G G A,Oliveira P V,Yang L.Determination of europium isotope ratios in natural waters by MC-ICPMS[J].Journal of Analytical Atomic Spectrometry,2017,32:987-995.
[16]Dominique W,Bruno K,Claude M,et al.High-precision isotopic characterization of USGS reference materials by TIMS and MC-ICP-MS[J].Geochemistry,Geophysics,Geosystems,2006,7(8):1-30.
[17]袁永海,元志红.微波消解-磷钼蓝分光光度法测定钨矿石中的磷含量[J].中国无机分析化学,2015,5(1):24-27.Yuan Y H,Yuan Z H.Determination of phosphorus in tungsten ores by microwave digestion-phosphorus molybdenum blue spectrophotometry[J].Chinese Journal of Inorganic Analytical Chemistry,2015,5(1):24-27.
[18]袁永海,尹昌慧,元志红,等.氢化物发生-原子荧光光谱法同时测定锡矿石中的砷和锑[J].冶金分析,2016,36(3):39-43.Yuan Y H,Yin C H,Yuan Z H,et al.Determination of arsenic and antimony in tin ore by hydride generationatomic fluorescence spectrometry[J].Metallurgical Analysis,2016,36(3):39-43.
[19]黎卫亮,程秀花,李忠煜,等.碱熔共沉淀-电感耦合等离子体质谱法测定橄榄岩中的稀土元素[J].岩矿测试,2017,36(5):468-473.Li W L,Cheng X H,Li Z Y,et al.Determination of rare earth elements in peridotite by inductively coupled plasma-mass spectrometry after alkali fusion and Mg(OH)2and Fe(OH)3coprecipitation[J].Rock and Mineral Analysis,2017,36(5):468-473.
[20]李潮峰,李献华,郭敬辉,等.微量岩石样品中Rb-Sr和Pb一步分离及高精度热电离质谱测试[J].地球化学,2011,40(5):399-406.Li C F,Li X H,Guo J H,et al.Single-step separation of Rb-Sr and Pb from minor rock samples and high precision determination using thermal ionization mass spectrometry[J].Geochemical,2011,40(5):399-406.