Abstract
Some elements normally occur at trace levels while the majority of natural geological materials may be exceedingly enriched in some special cases, such as the Bayan Obo ore deposit where REE and Nb are extremely enriched. These elements may not be removed completely during purification. Therefore, matrix effects will be caused during stable isotope ratio measurement in the MC-ICP-MS. Experiments have shown that the established methods of chromatographic separation of Cu, Fe, and Zn using AG MP-1 Anion Exchange Resin cannot make effective separation of Nb, W, and Cu from Fe using 20 mL 6 M HCl. It is also observed that the elution curves of W and Cu overlap at working conditions and thus W is present in measurable amounts in some sample solutions. Matrix effects in the MC-ICP-MS induced by Nb, W, and Cu during Fe isotope ratio measurements and by W during Cu isotope ratio measurements were thus investigated by examining their changes in delta values between doped and undoped standards. The results show that the effects of the matrix elements Nb, W, or Cu on Fe isotope ratio measurements are minimal in the case of m(Nb)/m(Fe)<0.005, m(W)/m(Fe)<0.01, or m(Cu)/m(Fe)<0.6. This finding, combined with the extremely low levels of W and Cu, and the fact that nearly 90% of Nb can be removed during purification, demonstrates that the methods of chromatographic separation of Fe established before are suitable for Bayan Obo ore samples and that the methods can be simplified when Cu elution is unnecessary. The effects of the matrix element W on Cu isotope determinations are minimal in the case of m(W)/m(Cu)<0.7. Therefore, W exerts no significant effect on the measurements of Cu isotopes for the majority of natural geological materials.
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References
Albarede F. and Beard B. (2004) Analytical methods for non-traditional isotopes [J]. Reviews in Mineralogy and Geochemistry. 55, 113–152.
Anbar A.D. (2004) Iron stable isotopes: Beyond biosignatures [J]. Earth and Planetary Science Letters. 217, 223–236.
Beard B.L. and Johnson C.M. (1999) High precision iron isotope measurements of terrestrial and lunar materials [J]. Geochimica et Cosmochimica Acta. 63, 1653–1660.
Beard B.L., Johnson C.M., Von Damm K.L., and Poulson R.L. (2003) Iron isotope constraints on Fe cycling and mass balance in oxygenated Earth oceans [J]. Geology. 31, 629–632.
Dauphas N. and Rouxel O. (2006) Mass spectrometry and natural variations of iron isotopes [J]. Mass Spectrometry Reviews. 25, 515–550.
Dauphas N., Janney P.E., Mendybaev R.A., Wadhwa M., Richter F.M., Davis A.M., Van Zuilen M., Hines R., and Foleys C.N. (2004) Chromatographic separation and multicollection-ICPMS analysis of iron: Investigating mass-dependent and-independent isotope effects [J]. Anal. Chem. 76, 5855–5863.
Johnson C.M., Beard B L., and Roden E.E. (2008) The iron isotope fingerprints of redox and biogeochemical cycling in modern and ancient Earth [J]. Annual Review of Earth and Planetary Sciences. 36, 457–493.
Marechal C.N., Telouk P., and Albarede F. (1999) Precise analysis of copper and zinc isotopic compositions by plasma-source mass spectrometry [J]. Chemical Geology. 156, 251–273.
McDonough W.F. (1995) The composition of the Earth [J]. Chemical Geology. 120, 223–253.
Rudnick R.L. and Gao Shan (2003) Composition of the continental crust [J]. Treatise on Geochemistry. 3, 1–64.
Sun Jian, Zhu Xiangkun, Tang Suohan, and Chen Yuelong (2010) Further investigation on elemental separation using AG MP-1 Anion Exchange Resin [J]. Geoscience. 24, 48–51 (in Chinese with English abstract).
Sun Jian, Zhu Xiangkun, Chen Yuelong, and Fang Nan (2012) Fe isotope compositions of related geological formation in Bayan Obo area and their comstrains on the geneis of Bayan Obo ore deposit [J]. Acta Geologica Sinica. 86, 819–828 (in Chinese with English abstract).
Tang Suohan and Zhu Xiangkun (2006a) Separation of some elements using AG MP-1 Anion Exchange Resin [J]. Geological Journal of China Universities. 12, 116–121 (in Chinese with English abstract).
Tang Suohan, Zhu Xiangkun, Cai Junjun, Li Shizhen, He Xuexian, and Wang Jinhui (2006b) Chromatographic separation of Cu, Fe and Zn using AG MP-1 Anion Exchange Resin for isotope determination by MC-ICPMS [J]. Rock and Mineral Analysis. 25, 11–14 (in Chinese with English abstract).
Zhang Zongqing, Yuan Zhongxin, Tang Suohan, Bai Ge, and Wang Jinhui (2003) Age and Geochemistry of the Bayan Obo Ore Deposit [M]. Geological Publishing House, Beijing (in Chinese).
Zhu Xiangkun, Guo Yueling, O’Nions R.K., Young E.D., and Ash R.D. (2001) Isotopic homogeneity of iron in the early solar nebula [J]. Nature. 412, 311–313.
Zhu Xiangkun, Guo Yueling, Williams R.J.P., O’Nions R.K., Matthews A., Belshaw N.S., Canters G.W., de Waal E.C., Weser U., Burgess B.K., and Salvato B. (2002) Mass fractionation processes of transition metal isotopes [J]. Earth and Planetary Science Letters. 200, 1–2.
Zhu Xiangkun, Li Zhihong, Zhao Xinmiao, Tang Suohan, He Xuexian, and Belshaw N.S. (2008) High-precision measurements of Fe isotopes using MC-ICP-MS and Fe isotope compositions of geological reference materials [J]. Acta Petrol. et Miner. 27, 263–272 (in Chinese with English abstract).
Zhu Xiangkun, O’Nions R.K., Guo Yueling, and Reynolds Ben C. (2000a) Secular variation of iron isotopes in North Atlantic Deep Water [J]. Science. 287, 2000–2002.
Zhu Xiangkun, O’Nions R.K., Guo Yueling, Belshaw N.S., and Rickard D. (2000b) Determination of natural Cu-isotope variation by plasma-source mass spectrometry: Implications for use as geochemical tracers [J]. Chemical Geology. 163, 139–149.
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Sun, J., Zhu, X., Tang, S. et al. Investigation of matrix effects in the MC-ICP-MS induced by Nb, W, and Cu: Isotopic case studies of iron and copper. Chin. J. Geochem. 32, 1–6 (2013). https://doi.org/10.1007/s11631-013-0600-z
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DOI: https://doi.org/10.1007/s11631-013-0600-z