Jump to main content
Jump to site search


An improved extraction chromatographic purification of tungsten from silicate matrix for high precision isotopic measurements using MC-ICPMS

Abstract

An improved chemical method is developed to accurately measure the W isotopic compositions of silicate samples with a precision of better than ± 0.05ε on ε182W. Compared with the conventional method, two developments of this method mainly include the sample digestion process that is modified to better the W dissolution from the co-precipitations and the W separation procedure. The optimized extraction chromatography using TEVA resin is designed to more efficiently separate W from Ti, Zr and Hf after first-stage cation-exchange procedure with the percent recovery of W more than 85%. The blank during the whole procedure is less than 0.3 ng and is negligible for W isotopic analysis. The W isotopic ratios of Alfa Aesar W standard solution and a variety of silicate reference materials, i.e., RGM-2, GSP-2, AGV-2, JB-3, BCR-2 and BHVO-2, are measured by multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). The RGM-2, GSP-2, AGV-2, JB-3 and BCR-2 have normal ε182W values, identical to that of the terrestrial Alfa Aesar W standard, whereas the BHVO-2 has a negative ε182W value of -0.09 ± 0.05 (2SD, N = 10). The duplicate measurements of Alfa Aesar W standard solution, RGM-2 and BHVO-2 show that the external reproducibility of the ε182W is usually better than 5 ppm (2SD), which is the most precise among the published data measured by MC-ICPMS and can be comparable to the precision acquired by using negative thermal ionization mass spectrometry (N-TIMS) (about 5 ppm). All these results show that our new method provides an efficient way to precisely measure W isotopic compositions of silicate materials. It provides a widely useful tool to reveal the earliest history of the silicate Earth and offers the ability to resolve sub-million-year age differences in meteorites.

Back to tab navigation

Supplementary files

Publication details

The article was accepted on 06 Feb 2018 and first published on 06 Feb 2018


Article type: Paper
DOI: 10.1039/C8JA00024G
Citation: J. Anal. At. Spectrom., 2018, Accepted Manuscript
  •   Request permissions

    An improved extraction chromatographic purification of tungsten from silicate matrix for high precision isotopic measurements using MC-ICPMS

    Q. Mei, J. Yang and Y. Yang, J. Anal. At. Spectrom., 2018, Accepted Manuscript , DOI: 10.1039/C8JA00024G

Search articles by author

Spotlight

Advertisements