Accurate Analysis of Lithium Isotopic Composition of Geological Samples by MC-ICP-MS
LIN Jie, LIU Yong-sheng, HU Zhao-chu, CHEN Kang, CHEN Hai-hong, ZONG Ke-qing, GAO Shan
State Key Laboratory of Geological Processes and Mineral Resources, School of Earth Sciences, China University of Geosciences(Wuhan), Wuhan 430074, China
Abstract：A method for accurate measurement of Li isotopic ratio by SSB-MC-ICP-MS has been set up. Li purification can be implemented by single chemical separation method, in which 1 mol/L HNO3/80%(V/V) CH3OH was used as the eluent. Effects of sample type and MgLi in samples on the elution process were also investigated. The residual ions in the sample after separation can compromise the accuracy and precision of Li isotopic ratios, but the results show no discernable matrix-induced mass discrimination on Li isotopic measurement even though the residual ion/Li ratio was up to 10. After the Li memory effect being eliminated with the 5% NaCl solution, the effect arouse by the mismatch of Li and acid concentration in sample and standard can be reduced. So a non-strict-matrix-matched method can be applied to accurate and precise measurement of Li isotopic ratios.
