Single-step chromatographic isolation of lithium from whole rock carbonate and clay for isotopic analysis with multi-collector ICP-mass spectrometry

Lithium isotope ratios play a key role in tracing weathering processes within the context of paleoclimatologic research. Therefore, accurate and precise determination of the isotopic composition of Li is required for a large variety of complex geological samples with widely different Li contents. This technical note describes the extension and fine-tuning of the existing cation exchange chromatographic procedures for isolation of Li to whole-rock carbonate and clay matrices. The method developed permits the isolation of [greater-than-or-equal]20 ng amounts of Li from carbonates and clays, by using a 25 cm long cylindrical column loaded with 8 and 2 mL of AG-50W-X8 cation exchange resin, respectively. A 0,5 M HCl solution is used as eluent. Li recoveries [greater-than-or-equal] 99 % were achieved and isotopic analysis of the Li isolates using multi-collector ICP-mass spectrometry resulted in accurate and precise ?7Li values (external precision (2SE) of 0.2 [per thousand] (N=15)). The analytical procedures developed allow Li isotope ratios to be investigated in parallel in both the clay and carbonate fractions of a geological sample within the context of paleoclimatological research.

Jaar van publicatie:2015

Trefwoorden:Lithium, Cretaceous-Tertiary boundary, MC-ICP-MS

CSS-citation score:2