High Precision Strontium Isotope Measurement of Rock Standard Materials by Multi-dynamic TIMS

WEI Yuqiu; HU Yating; ZHOU Lian; HU Zhaochu; FENG Lanping

doi:10.15898/j.ykcs.202308020120

2023 Vol. 42, No. 5

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WEI Yuqiu, HU Yating, ZHOU Lian, HU Zhaochu, FENG Lanping. High Precision Strontium Isotope Measurement of Rock Standard Materials by Multi-dynamic TIMS[J]. Rock and Mineral Analysis, 2023, 42(5): 944-956. doi: 10.15898/j.ykcs.202308020120

Citation:

WEI Yuqiu, HU Yating, ZHOU Lian, HU Zhaochu, FENG Lanping. High Precision Strontium Isotope Measurement of Rock Standard Materials by Multi-dynamic TIMS[J]. Rock and Mineral Analysis, 2023, 42(5): 944-956. doi: 10.15898/j.ykcs.202308020120

High Precision Strontium Isotope Measurement of Rock Standard Materials by Multi-dynamic TIMS

State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences (Wuhan), Wuhan 430074, China

More Information

Corresponding author: FENG Lanping, lanping@cug.edu.cn

Received Date: 02 August 2023

Revised Date: 10 September 2023

Accepted Date: 17 September 2023

Publish Date: 31 October 2023

Abstract

Abstract

BACKGROUND
Strontium isotopes are a powerful geochemical indicator for tracing the sources and ages of ore-forming materials. TIMS is internationally recognized as the “gold standard” for determining Sr isotopic compositions, however, its analysis accuracy is severely limited by the attenuation of Faraday cup efficiency. How to effectively eliminate the influence of Faraday cup efficiency change is the key to improving the accuracy of Sr isotopes measured by TIMS. In addition, matrix reference materials are crucial for validating measurements on geological samples. Therefore, it is necessary to calibrate the Sr isotope composition of new geological reference materials to replace the unavailable standards (e.g., USGS).
OBJECTIVES
To develop a high-precision Sr isotope analysis method using multi-dynamic TIMS and accurately calibrate a set of GBW reference materials with varying sample matrices.
METHODS
Samples were completely digested by the high-pressure bomb method. Complete separation of Sr from sample matrices was accomplished through a two-stage column separation method consisting of ion exchange resin (AG 50X-12) and extraction resin (Sr spec). Sr isotopes were measured using a multi-collector TIMS and collected in a three-lines cup configuration. The internal normalization method was used to correct for instrument mass bias, and the multi-dynamic collection method was employed to mitigate the effects of Faraday cup efficiency drift.
RESULTS
(1) Significant Faraday cup deterioration (up to 160μg/g on C cup) was observed during an 8 months Sr isotope analytical session. Nevertheless, the results from the Monte Carlo simulation indicate that the multi-dynamic collection method can eliminate 99.6% of the cup coefficient effect. Moreover, long-term testing of NBS987 shows that employing the multi-dynamic collection method results in an instrumental precision of 8μg/g, which is 2-3 times more accurate than traditional static collection methods. Overall, results from both theoretical predictions and practical testing confirmed that the multi-dynamic collection method can effectively eliminate the effects of the cup effect drift. (2) The Sr recovery of the leaching experiments for BCR-2 and BHVO-2 with AG 50W-X8 resin column were 99.16% and 98.91%, respectively. The total Sr recovery of the two-stage columns was as high as 95%, thus preventing any potential Sr isotope fractionation resulting from Sr losses during the column separation process. Furthermore, the total blank throughout the entire procedure was no higher than 150pg for Sr, which was negligible compared to the large sample size. (3) High precision Sr isotope compositions were determined for 13 geological reference samples with various sample matrices, resulting in ⁸⁷Sr/⁸⁶Sr ratio measurements ranging from 0.704078 to 0.807402. Among these results, GBW07104, GBW07105, GBW07106, and GBW07108 were found to be consistent with previously reported values within the uncertainties and the other nine reference materials were reported herein for the first time.
CONCLUTIONS
The cup effect can significantly impact the Sr isotope measured by MC-TIMS, but it can be effectively mitigated by using a multi-dynamic collection method. Furthermore, independent test results demonstrate the uniformity of the Sr isotope composition in these GBW standards, rendering them suitable for both quality control and interlaboratory comparison purposes.
- multi-dynamic collection /
- MC-TIMS /
- cup efficiency /
- strontium isotope /
- GBW reference materials

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References

[1]	韦刚健, 刘颖, 涂湘林, 等. 利用选择性特效树脂富集分离岩石样品中的锶钐和钕[J]. 岩矿测试, 2004, 23(1): 11−14. doi: 10.3969/j.issn.0254-5357.2004.01.003 CrossRef Google Scholar Wei G J, Liu Y, Tu X L, et al. Separation of Sr, Sm and Nd in mineral and rock samples using selective specific resins[J]. Rock and Mineral Analysis, 2004, 23(1): 11−14. doi: 10.3969/j.issn.0254-5357.2004.01.003 CrossRef Google Scholar
[2]	赵葵东, 蒋少涌. 金属矿床的同位素直接定年方法[J]. 地学前缘, 2004, 11(2): 425−434. doi: 10.3321/j.issn:1005-2321.2004.02.012 CrossRef Google Scholar Zhao K D, Jiang S Y. Direct isotope dating for metallic ore deposits[J]. Earth Science Frontiers, 2004, 11(2): 425−434. doi: 10.3321/j.issn:1005-2321.2004.02.012 CrossRef Google Scholar
[3]	Li C F, Chu Z Y, Wang X C, et al. Sr isotope analysis of picogram-level samples by thermal ionization mass spectrometry using a highly sensitive silicotungstic acid emitter[J]. Analytical Chemistry, 2019, 91(11): 7288−7294. doi: 10.1021/acs.analchem.9b00958 CrossRef Google Scholar
[4]	Yang Y H, Yang M, Jochum K P, et al. High-precision Sr-Nd-Hf-Pb isotopic composition of Chinese geological standard glass reference materials CGSG-1, CGSG-2, CGSG-4 and CGSG-5 by MC-ICP-MS and TIMS[J]. Geostandards and Geoanalytical Research, 2020, 44(3): 567−579. doi: 10.1111/ggr.12322 CrossRef Google Scholar
[5]	Luu T H, Gutiérrez P, Inglis E C, et al. High-precision Sr and Nd isotope measurements using a dynamic zoom lens-equipped thermal ionisation mass spectrometer[J]. Chemical Geology, 2022, 611: 121078. doi: 10.1016/j.chemgeo.2022.121078 CrossRef Google Scholar
[6]	Di Y, Krestianinov E, Zink S, et al. High-precision multidynamic Sr isotope analysis using thermal ionization mass spectrometer (TIMS) with correction of fractionation drift[J]. Chemical Geology, 2021, 582: 120411. doi: 10.1016/j.chemgeo.2021.120411 CrossRef Google Scholar
[7]	Thirlwall M F, Anczkiewicz R. Multidynamic isotope ratio analysis using MC-ICP-MS and the causes of secular drift in Hf, Nd and Pb isotope ratios[J]. International Journal of Mass Spectrometry, 2004, 235(1): 59−81. doi: 10.1016/j.ijms.2004.04.002 CrossRef Google Scholar
[8]	Makishima A, Nakamura E. Calibration of Faraday cup efficiency in a multicollector mass spectrometer[J]. Chemical Geology, 1991, 94(2): 105−110. doi: 10.1016/0168-9622(91)90003-F CrossRef Google Scholar
[9]	Miyazaki T, Vaglarov B S, Kimura J I. Determination of relative Faraday cup efficiency factor using exponential law mass fractionation model for multiple collector thermal ionization mass spectrometry[J]. Geochemical Journal, 2016, 50(5): 445−447. doi: 10.2343/geochemj.2.0439 CrossRef Google Scholar
[10]	Krabbenhöft A, Fietzke J, Eisenhauer A, et al. Determination of radiogenic and stable strontium isotope ratios (⁸⁷Sr/⁸⁶Sr; δ⁸⁸/⁸⁶Sr) by thermal ionization mass spectrometry applying an ⁸⁷Sr/⁸⁴Sr double spike[J]. Journal of Analytical Atomic Spectrometry, 2009, 24(9): 1267. doi: 10.1039/b906292k CrossRef Google Scholar
[11]	Di Y, Li Z, Amelin Y. Monitoring and quantitative evaluation of Faraday cup deterioration in a thermal ionization mass spectrometer using multidynamic analyses of laboratory standards[J]. Journal of Analytical Atomic Spectrometry, 2021, 36(7): 1489−1502. doi: 10.1039/D1JA00028D CrossRef Google Scholar
[12]	Yobregat E, Fitoussi C, Bourdon B. A new method for TIMS high precision analysis of Ba and Sr isotopes for cosmochemical studies[J]. Journal of Analytical Atomic Spectrometry, 2017, 32(7): 1388−1399. doi: 10.1039/C7JA00012J CrossRef Google Scholar
[13]	Feng L, Zhou L, Yang L, et al. Optimization of double spike technique using peak jump collection by Monte Carlo method: An example for the determination of Ca isotope ratios[J]. Journal of Analytical Atomic Spectrometry, 2015, 30(12): 2403−2411. doi: 10.1039/C5JA00203F CrossRef Google Scholar
[14]	Yang L, Tong S, Zhou L, et al. A critical review on isotopic fractionation correction methods for accurate isotope amount ratio measurements by MC-ICP-MS[J]. Journal of Analytical Atomic Spectrometry, 2018, 33(11): 1849−1861. doi: 10.1039/C8JA00210J CrossRef Google Scholar
[15]	Guo K, Yu J, Fan D, et al. Precise determination of Sr and Nd isotopic compositions of Chinese standard reference samples GSR-1, GSR-2, GSR-3 and GBW07315 by TIMS[J]. Geosystems and Geoenvironment, 2023, 2(4): 100206. doi: 10.1016/j.geogeo.2023.100206 CrossRef Google Scholar
[16]	唐索寒, 李津, 潘辰旭, 等. 岩石铷-锶和钐-钕同位素标准物质的研制[J]. 岩矿测试, 2021, 40(2): 285−295. doi: 10.15898/j.cnki.11-2131/td.202011110140 CrossRef Google Scholar Tang S H, Li J, Pan C X, et al. Preparation of the reference materials for Rb-Sr and Sm-Nd isotope analysis[J]. Rock and Mineral Analysis, 2021, 40(2): 285−295. doi: 10.15898/j.cnki.11-2131/td.202011110140 CrossRef Google Scholar
[17]	Birck J L. Precision K-Rb-Sr isotopic analysis: Application to Rb-Sr chronology[J]. Chemical Geology, 1986, 56(1-2): 73−83. doi: 10.1016/0009-2541(86)90111-7 CrossRef Google Scholar
[18]	Charlier B L A, Ginibre C, Morgan D, et al. Methods for the microsampling and high-precision analysis of strontium and rubidium isotopes at single crystal scale for petrological and geochronological applications[J]. Chemical Geology, 2006, 232(3-4): 114−133. doi: 10.1016/j.chemgeo.2006.02.015 CrossRef Google Scholar
[19]	Meynadier L, Gorge C, Birck J L, et al. Automated separation of Sr from natural water samples or carbonate rocks by high performance ion chromatography[J]. Chemical Geology, 2006, 227(1-2): 26−36. doi: 10.1016/j.chemgeo.2005.05.012 CrossRef Google Scholar
[20]	贺茂勇, 逯海, 金章东, 等. 人牙齿中锶的特效树脂分离及其同位素测定[J]. 分析化学, 2012, 40(7): 1109−1113. Google Scholar He M Y, Lu H, Jin Z D, et al. Separation and isotopic measurement of Sr in tooth samples using selective specific resins[J]. Chinese Journal of Analytical Chemistry, 2012, 40(7): 1109−1113. Google Scholar
[21]	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]. Analytica Chimica Acta, 2012, 727: 54−60. doi: 10.1016/j.aca.2012.03.040 CrossRef Google Scholar
[22]	刘文刚, 刘卉, 李国占, 等. 离子交换树脂在地质样品Sr-Nd同位素测定中的应用[J]. 地质学报, 2017, 91(11): 2584−2592. doi: 10.3969/j.issn.0001-5717.2017.11.013 CrossRef Google Scholar Liu W G, Liu H, Li G Z, et al. The apllication of ion exchange resins in Sr-Nd isotopic assay of geological samples[J]. Acta Geologica Sinica, 2017, 91(11): 2584−2592. doi: 10.3969/j.issn.0001-5717.2017.11.013 CrossRef Google Scholar
[23]	Yang Y H, Wu F Y, Liu Z C, et al. Evaluation of Sr chemical purification technique for natural geological samples using common cation-exchange and Sr-specific extraction chromatographic resin prior to MC-ICP-MS or TIMS measurement[J]. Journal of Analytical Atomic Spectrometry, 2012, 27(3): 516−522. doi: 10.1039/c2ja10333h CrossRef Google Scholar
[24]	Horwitz E P, Dietz M L, Fisher D E. Separation and preconcentration of strontium from biological, environmental, and nuclear waste samples by extraction chromatography using a crown ether[J]. Analytical Chemistry, 1991, 63(5): 522−525. doi: 10.1021/ac00005a027 CrossRef Google Scholar
[25]	Pin C, Gannoun A, Dupont A. Rapid, simultaneous separation of Sr, Pb, and Nd by extraction chromatography prior to isotope ratios determination by TIMS and MC-ICP-MS[J]. Journal of Analytical Atomic Spectrometry, 2014, 29(10): 1858−1870. doi: 10.1039/C4JA00169A CrossRef Google Scholar
[26]	徐卓, 李力力, 朱留超, 等. Eichrom Sr树脂用于铀矿浓缩物中铅锶的分离富集研究[J]. 岩矿测试, 2019, 38(1): 55−61. Google Scholar Xu Z, Li L L, Zhu L C, et al. Application of Eichrom Sr resin to the separation and enrichment of lead and strontium in uranium ore concentrates[J]. Rock and Mineral Analysis, 2019, 38(1): 55−61. Google Scholar
[27]	Misawa K, Yamazaki F, Ihira N, et al. Separation of rare earth elements and strontium from chondritic meteorites by miniaturized extraction chromatography for elemental and isotopic analyses[J]. Geochemical Journal, 2000, 34(1): 11−21. doi: 10.2343/geochemj.34.11 CrossRef Google Scholar
[28]	Smet I, Muynck D D, Vanhaecke F, et al. From volcanic rock powder to Sr and Pb isotope ratios: A fit-for-purpose procedure for multi-collector ICP-mass spectrometric analysis[J]. Journal of Analytical Atomic Spectrometry, 2010, 25(7): 1025−1032. doi: 10.1039/b926335g CrossRef Google Scholar
[29]	Li C F, Chu Z Y, Guo J H, et al. A rapid single column separation scheme for high-precision Sr-Nd-Pb isotopic analysis in geological samples using thermal ionization mass spectrometry[J]. Analytical Methods, 2015, 7(11): 4793−4802. doi: 10.1039/C4AY02896A CrossRef Google Scholar
[30]	Wieser M E, Buhl D, Bouman C, et al. High precision calcium isotope ratio measurements using a magnetic sector multiple collector inductively coupled plasma mass spectrometer[J]. Journal of Analytical Atomic Spectrometry, 2004, 19(7): 844−851. doi: 10.1039/b403339f CrossRef Google Scholar
[31]	Ludwig K R. Optimization of multicollector isotope-ratio measurement of strontium and neodymium[J]. Chemical Geology, 1997, 135(3-4): 325−334. doi: 10.1016/S0009-2541(96)00120-9 CrossRef Google Scholar
[32]	Holmden C, Bélanger N. Ca isotope cycling in a forested ecosystem[J]. Geochimica et Cosmochimica Acta, 2010, 74(3): 995−1015. doi: 10.1016/j.gca.2009.10.020 CrossRef Google Scholar
[33]	Wang Y, He Y, Wang Z N, et al. High-precision calcium isotope analysis on TIMS using a double spike technique: The instrumental drift and its correction[J]. Atomic Spectroscopy, 2023, 44(1): 45−54. Google Scholar
[34]	Yang Y H, Zhang H F, Chu Z Y, et al. Combined chemical separation of Lu, Hf, Rb, Sr, Sm and Nd from a single rock digest and precise and accurate isotope determinations of Lu-Hf, Rb-Sr and Sm-Nd isotope systems using multi-collector ICP-MS and TIMS[J]. International Journal of Mass Spectrometry, 2010, 290(2): 120−126. Google Scholar
[35]	杨林, 石震, 于慧敏, 等. 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[J]. 岩矿测试, 2023, 42(1): 136−145. doi: 10.3969/j.issn.0254-5357.2023.1.ykcs202301010 CrossRef Google Scholar Yang L, Shi Z, Yu H M, et al. Determination of silicon isotopic compositions of rock and soil reference materials by MC-ICP-MS[J]. Rock and Mineral Analysis, 2023, 42(1): 136−145. doi: 10.3969/j.issn.0254-5357.2023.1.ykcs202301010 CrossRef Google Scholar
[36]	Liu F, Li X, Zhang Z, et al. Calcium isotope ratios ( δ^44/40Ca) of thirty-four geological Chinese reference materials measured by thermal ionisation mass spectrometry (TIMS)[J]. Geostandards and Geoanalytical Research, 2022, 46(2): 307−319. doi: 10.1111/ggr.12418 CrossRef Google Scholar
[37]	Wu G, Zhu J M, Wang X, et al. High-sensitivity measurement of Cr isotopes by double spike MC-ICP-MS at the 10ng level[J]. Analytical Chemistry, 2020, 92(1): 1463−1469. doi: 10.1021/acs.analchem.9b04704 CrossRef Google Scholar
[38]	Chen X Q, Zeng Z, Yu H M, et al. Precise measurements of δ^88/86Sr for twenty geological reference materials by double-spike MC-ICP-MS[J]. International Journal of Mass Spectrometry, 2022, 479: 116883. doi: 10.1016/j.ijms.2022.116883 CrossRef Google Scholar
[39]	Fourny A, Weis D, Scoates J S. Comprehensive Pb-Sr-Nd-Hf isotopic, trace element, and mineralogical characterization of mafic to ultramafic rock reference materials[J]. Geochemistry, Geophysics, Geosystems, 2016, 17(3): 739−773. doi: 10.1002/2015GC006181 CrossRef Google Scholar
[40]	Wu S, Yang Y, Jochum K P, et al. Isotopic compositions (Li-B-Si-O-Mg-Sr-Nd-Hf-Pb) and Fe²⁺/ΣFe ratios of three synthetic andesite glass reference materials (ARM-1, ARM-2, ARM-3)[J]. Geostandards and Geoanalytical Research, 2021, 45(4): 719−745. doi: 10.1111/ggr.12399 CrossRef Google Scholar
[41]	Zhang Z, Ma J, Zhang L, et al. Rubidium purification via a single chemical column and its isotope measurement on geological standard materials by MC-ICP-MS[J]. Journal of Analytical Atomic Spectrometry, 2018, 33(2): 322−328. doi: 10.1039/C7JA00406K CrossRef Google Scholar