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Accurate Measurement of Lithium Isotopes in Eleven Carbonate Reference Materials by MC ‐ ICP ‐ MS with Soft Extraction Mode and 10 12 Ω Resistor High‐Gain Faraday Amplifiers
Author(s) -
Lin Jie,
Liu Yongsheng,
Hu Zhaochu,
Chen Wei,
Zhang La,
Chen Haihong
Publication year - 2019
Publication title -
geostandards and geoanalytical research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.037
H-Index - 73
eISSN - 1751-908X
pISSN - 1639-4488
DOI - 10.1111/ggr.12260
Subject(s) - carbonate , lithium carbonate , silicate , isotope , mineralogy , chemistry , analytical chemistry (journal) , geology , environmental chemistry , ion , physics , organic chemistry , quantum mechanics , ionic bonding
Lithium isotopes in carbonate rocks and minerals can serve as important tools for assessing palaeoclimates and palaeoenvironments. However, carbonate bulk rock samples are commonly mixtures of carbonate and silicate minerals, which require the complete digestion of the carbonate without digesting the silicate. Additionally, the low Li content (ng g −1 level) in carbonates provides an additional challenge. Hence, despite their wide applications, few carbonates have had their δ 7 Li values characterised, particularly carbonate reference materials, which hinders comparisons of Li isotope measurement results obtained in different laboratories and the further application of Li isotopes in geological studies. This study aimed to provide precise and accurate δ 7 Li values for carbonate reference materials based on an evaluation of sample leaching and the Li purification method for carbonates, as well as the adoption of soft extraction and 10 12 Ω amplifiers to increase the intensity/blank ratio and matrix effect on Li isotope measurement. The precision and accuracy of the proposed procedure were verified by analysing synthetic carbonate samples and mono‐elemental Li solutions. With the developed method we provide δ 7 Li values for eleven carbonate reference materials with a precision of ~ 0.4‰. The accuracy of the δ 7 Li values was validated using the standard addition method.