年代学-陈福坤-第二节-实验室.pdf

同位素地质年代学与 放射成因同位素地球化学 同位素地质年代学与 放射成因同位素地球化学 陈福坤 固体同位素地球化学实验室固体同位素地球化学实验室 中国科学院地质与地球物理研究所 实验室介绍实验室介绍 放射性成因同位素实验室放射性成因同位素实验室 1. 超净化环境下化学前处理 －同位素分离和纯化 超净化环境下化学前处理 －同位素分离和纯化 2. 质谱计 －同位素比值测定 质谱计 －同位素比值测定 中国科学院地质与地球物理研究所 固体同位素地球化学实验室 Laboratory for Radiogenic Isotope Geochemistry 主要装备 1、、200 m2 ultra-clean laboratory 8 clean-rooms for chemical separation 2、、3 mass spectrometers VG354 、、MAT262 、、IsoProbe-T 3、、Sm-Nd、、Rb-Sr、、Pb-Pb 、、U-Pb Clean roomClean room FinniganFinnigan MAT262 Mass SpectrometerMAT262 Mass Spectrometer 固体同位素质谱计 德国Fi n n i g a n 公司M A T - 2 6 2 VG 354 Mass SpectrometerVG 354 Mass SpectrometerVG 354 Mass Spectrometer 固体同位素质谱计 英国VG 公司 VG - 354 新型高精度固体同位素质谱计 英国G V公司I s o Pr o b e - T （安装调试中） IsoProbe-T High-Precision TIMS IsoProbe-T High-Precision TIMS 9 Fa r a d a y ，1 D a l y ，7 I o n c o u n t i n g s9 Fa r a d a y ，1 D a l y ，7 I o n c o u n t i n g s9 Fa r a d a y ，1 D a l y ，7 I o n c o u n t i n g s9 Fa r a d a y ，1 D a l y ，7 I o n c o u n t i n g s A product from the GV company MicroMassA product from the GV company MicroMass 固体同位素地球化学实验室 今后的任务与发展方向 打造良好实验工作环境 规范化学流程和质谱计操作 规范实验室开放管理 完善实验室的开放条件 开放方式 利用现有实验条件分析测试 携手开发新方法和开拓应用领域 同位素年代学和同位素地球化学 高精度、精细 微量/ 超微量 实验室的发展方向 铼－锇同位素体系 微区钕－锶－铅体系 同位素地球化学示踪 同位素年代学 单颗粒锆石定年 微量钐－钕和铷－锶矿物 陈福坤 办公室电话 0 10 - 6 2 0 0 742 8 手机139 112 0 6 175 电子邮件f u k u n - c h e n ma i l . i g c a s . a c . c n 储著银0 10 - 6 2 0 0 78 43；6 2 0 0 78 44 z h y c h u ma i l . i g c a s . a c . c n 李潮峰0 10 - 6 2 0 0 78 44 l i c h a o f 59 8 5s i n a . c o m 放射成因同位素地球化学 实验方法与流程 A n a l y t i c a l p r o c e d u r e f o r i s o t o p i c g e o c h e mi s t r y Chemical separation and purification Measurement of isotopic ratios Valuation of analytical data Chromatography Sample digestion 超净化实验室环境下 同位素分离纯化 为什么超净化环境 － 样品中待分析组分含量低 － 降低环境和人为因素对样品的影响， 即降低实验室本底 如何尽可能降低本底 － 净化实验室空气 － 净化化学试剂和器皿 超净化实验室 在超净化实验室工作的学生 超净化实验室的水纯化系统 超净化实验室的亚沸酸纯化装置 超净化实验室的亚沸酸纯化装置 超净化实验室内化学器皿清洗 为什么分离和纯化样品 － 除去样品中其它元素的干扰 如Ca 、Fe 、M g 离子 － 除去同质异素的叠加 如 8 7R b 对8 7Sr 的叠加 144 Sm对144Nd 的叠加 150 Sm对150Nd 的叠加 Abundance 钐同位素对钕同位素的叠加 采用的分离纯化方法 － 离子交换树脂 － 蒸发提取 －萃取 R-H A R-A H 离子交换树脂工作原理 R-A H R-H A 铷－锶同位素分离纯化图例 Ion chromatography 净化操作台内离子树脂交换柱 －铷、锶和稀土元素分离 学生正在完成铷、锶和稀土元素分离工作 质谱计基本原理与 同位素比值测定 Mass spectrometer Device used to measure the mass of a given type of atom Mass spectrum Position of peaks give the atom mass Relative heights of the peaks indicate relative number of atoms of different masses Charged Particle Charged Particle in Magnet Fieldin Magnet Field Mass/Charge ratio m/qMass/Charge ratio m/q m Bm B 2 2 r r 2 2 q 2Vq 2V Major Components of Major Components of Mass SpectrometerMass Spectrometer v v v v v v v v 204204Pb Pb 206206Pb Pb 207207Pb Pb 208208Pb Pb Faraday CupFaraday Cup IonIon BeamBeam Magnet FieldMagnet Field A long history in Thermal Ionisation Mass Spectrometry TIMS since 1973 MM30- single collector. VG54E- single/double collector VG354- 5collector VG Sector- up to 9 collectors VG Sector 54- 9 collectors ESA MM Sector 54- 9 collectors WARP MM IsoProbe-T-9 collectors 7ion counters Features of the IsoProbe-T Wide Magnet and Flight Tube This permits the instrument to measure an 18 mass window at the collector. This will allow simultaneous measurement of the 6Liisotope and the 7Liisotope. Use of M 17 Multicollector Block Up to 17 collectors can be accommodated in this block with the possibility of including Multiple Ion Counters for the measurement of very small ion beams in the static mode. Features of the IsoProbe-T Fully automated positioning of Collectors A new multiple motor controller has been developed which provides feed-back of the collector position. New Windows NT based Software Suite The MassLynx software suite used throughout the Micromass product range has been extended to the Isotope ratio products. A completely new working interface, IsoLynx, has been developed which permits the direct use of Excel on the raw data produced by the machine. The User can readily construct complex data reduction routines which may be appropriate for a given analysis. IsoProbe-T MC-17 Multicollector Array IsoProbe-T MC-17 Multicollector Array L7CDML6CDML5CDML4CDML3L2AxialDaly/L1H1H2H3H4H5H6 Pb 204Pb206Pb207Pb208Pb232Th238U Hg/Pb 202Hg204Pb206Pb207Pb238U U 234U235U236U238U U 234U235U236U238U U/Pu 234U235U236U238UPu239Pu240Pu242Pu U 238U U/Th 230Th232Th235U238U Hg/Pb/U 202Hg204Pb206Pb207Pb208Pb238U Hg/Tl/Pb 203Tl204Pb205Tl206Pb207Pb208Pb Pt 190Pt192Pt194Pt195Pt196Pt198Pt Re/Os 185Re186Os187Os188Os189Os190Os192Os Os Seq 1 185Re186Os187Os188Os Os Seq 2 186Os187Os188Os189Os Os Seq 3 187Os188Os189Os190Os W 180W181Ta182W183W184W186W Lu/Yb/Hf 174Yb175Lu176Hf177Hf178Hf179Hf180Hf Ce/Sm/Nd 140Ce142Nd143Nd144Nd145Nd146Nd147Sm148Nd150Nd Sn 112Sn114Sn116Sn117Sn118Sn119Sn120Sn122Sn124Sn Cd 106Cd108Cd110Cd111Cd112Cd113Cd114Cd116Cd Mo 92Mo94Mo95Mo96Mo97Mo98Mo100Mo Zr 90Zr91Zr92Zr94Zr96Zr Kr/Rb/Sr 83Kr84Sr85Rb86Sr87Sr88Sr Se 74Se76Se77Se78Se78SeH80Se80SeH82Se Zn 64Zn66Zn67Zn68Zn70Zn Cu 63Cu65Cu Fe 54Fe56Fe57Fe58Fe 60Ni Cr 50Cr52Cr53Cr54Cr56Fe Ti 46Ti47Ti48Ti49Ti50Ti Ca 40Ca42Ca43Ca43.5Sr44Ca46Ca or 42Ca43Ca43.5Sr44Ca46Ca or 44Ca46Ca48Ca Mg 24Mg25Mg26Mg B 10B11B Li 6Li7Li L7CDML6CDML5CDML4CDML3L2AxialDaly/L1H1H2H3H4H5H6 Pb 204Pb206Pb207Pb208Pb232Th238U Hg/Pb 202Hg204Pb206Pb207Pb238U U 234U235U236U238U U 234U235U236U238U U/Pu 234U235U236U238UPu239Pu240Pu242Pu U 238U U/Th 230Th232Th235U238U Hg/Pb/U 202Hg204Pb206Pb207Pb208Pb238U Hg/Tl/Pb 203Tl204Pb205Tl206Pb207Pb208Pb Pt 190Pt192Pt194Pt195Pt196Pt198Pt Re/Os 185Re186Os187Os188Os189Os190Os192Os Os Seq 1 185Re186Os187Os188Os Os Seq 2 186Os187Os188Os189Os Os Seq 3 187Os188Os189Os190Os W 180W181Ta182W183W184W186W Lu/Yb/Hf 174Yb175Lu176Hf177Hf178Hf179Hf180Hf Ce/Sm/Nd 140Ce142Nd143Nd144Nd145Nd146Nd147Sm148Nd150Nd Sn 112Sn114Sn116Sn117Sn118Sn119Sn120Sn122Sn124Sn Cd 106Cd108Cd110Cd111Cd112Cd113Cd114Cd116Cd Mo 92Mo94Mo95Mo96Mo97Mo98Mo100Mo Zr 90Zr91Zr92Zr94Zr96Zr Kr/Rb/Sr 83Kr84Sr85Rb86Sr87Sr88Sr Se 74Se76Se77Se78Se78SeH80Se80SeH82Se Zn 64Zn66Zn67Zn68Zn70Zn Cu 63Cu65Cu Fe 54Fe56Fe57Fe58Fe 60Ni Cr 50Cr52Cr53Cr54Cr56Fe Ti 46Ti47Ti48Ti49Ti50Ti Ca 40Ca42Ca43Ca43.5Sr44Ca46Ca or 42Ca43Ca43.5Sr44Ca46Ca or 44Ca46Ca48Ca Mg 24Mg25Mg26Mg B 10B11B Li 6Li7Li Micromass’ Extended M-17 collector array Micromass’ Extended M-17 collector array Stability of gain on small Pb ion signal between 2 ion counting channels. 208Pb/207Pb static multiple ion counting. Each block 50 ten second integrations. Total time 80mins Errors are 1RSD 2.3800 2.3850 2.3900 2.3950 2.4000 024681012 block 208Pb/207Pb 2.39139/-0.04 1 RSD 208Pb 2.6e-14A MassLynx - NT for TIMS IsoLynx New MassLynx control screen 0.511836 0.511838 0.51184 0.511842 0.511844 0.511846 0.511848 0.51185 0.511852 0.511854 010203040 measurement Mean 0.511845815 1SD3ppm LaJolla Neodymium after 2nd order correction 2ndrun MIT HCT001 Installation data Multidynamic. Internal precision External Precision 0.512103 0.512104 0.512105 0.512106 0.512107 0.512108 0.512109 0.512110 0.512111 0.512112 0246810 Bead 143Nd/144Nd 0.512108/-0.000001 1SD 2.7ppm 1RSD Static measurements MIT HCT001 no gains between analyses over 4 days 0.512120 0.512122 0.512124 0.512126 0.512128 0.512130 0.512132 0.512134 0.512136 0246810 Bead 143Nd/144Nd 0.512128/-0.000003 1SD 5.5ppm 1RSD 参考书 Dickin, Alan P. 1995 Radiogenic Isotope Geology. Cambridge University Press reprinted in 1997, 2000, 2002. Faure, Gunter 2001 Origin of Igneous Rocks – The Isotopic Evidence. Springer. Rollinson, Hugh R. 1993 Using Geochemical Data Evolution, Presentation, Interpretation. John Wiley 2、Value of 87Rb/85Rb ratio of spike; 3、Concentration of the Rb spike； 4、Sample and spike are exactly weighted We have measured 87Rb/85Rb ratio for the mixture of the sample and spike, How can we obtain Rb concentration of the sample Rbmixture＝ Rbsample Rbspike 87Rbsam 87Rbspi 85Rbsam 85Rbspi 87Rb 85Rb mix 87Rb 85Rb measured 85Rb/87Rbsam a; 2.59265, constant value 85Rbsam a x 87Rbsam Weight of sample Wsamg Sample Atomic abundance and weight of Rb isotopes in natural sample 85Rb 72.17 ; 84.91174 87Rb 27.83 ; 86.90919 Value of atomic 85Rb/87Rb ratio 2.59265 85Rb/87Rbspi c; Spike Rb concentration CRb b mol/g Weight of spike Wspig Spike 85Rbspi c/c1 x b x Wspimol 87Rbspi 1/c1 x b x Wspimol 87Rbsam 87Rbspi 85Rbsam 85Rbspi 87Rb 85Rb measured 87Rbsam 1/c1*b*Wspi a*87Rbsam c/c1*b*Wspi 87Rbsam can be obtained 85Rbsam a x 87Rbsam Rbsam 87Rbsam 85Rbsam 1a x 87Rbsammol Total Rb of the sample Rb concentration of sample Csam Csam Rbsam/Wsammol/g Rbsam/Wsam x ARbg/g or ppm ARb average atom weight of Rb 85.4678 注意单位的变换 谢谢