Analytical and Bioanalytical Chemistry

, Volume 407, Issue 7, pp 1925–1935

A practical guide for the design and implementation of the double-spike technique for precise determination of molybdenum isotope compositions of environmental samples

Research Paper

DOI: 10.1007/s00216-014-8448-6

Cite this article as:
Skierszkan, E.K., Amini, M. & Weis, D. Anal Bioanal Chem (2015) 407: 1925. doi:10.1007/s00216-014-8448-6

Abstract

The isotopic double-spike method allows for the determination of stable isotope ratios by multi-collector inductively coupled plasma-mass spectrometry (MC-ICP-MS) with accuracy and precision in the range of ∼0.02 ‰ amu−1, but its adoption has been hindered by the perceived difficulties in double-spike calibration and implementation. To facilitate the implementation of the double-spike approach, an explanation of the calibration and validation of a 97Mo-100Mo double-spike protocol is given in more detail than has been presented elsewhere. The long-term external standard reproducibility is 0.05 ‰ on δ98/95Mo measurements of standards. δ98/95Mo values for seawater and U.S. Geological Survey (USGS) reference materials SDO-1 and BCR-2 measured in this study are 2.13 ± 0.04 ‰ (2 SD, n = 3), 0.79 ± 0.05 ‰ (2 SD, n = 11), and −0.04 ± 0.10 ‰ (2 SD, n = 3) relative to the NIST-SRM-3134. The double-spike method corrects for laboratory and instrumental fractionation which are not accounted for using other mass bias correction methods. Spike/sample molar ratios between 0.4 and 0.8 provide accurate isotope measurements; outside of this range, isotope measurements are inaccurate but corrections are possible when standards and samples are spiked at a similar ratio.

Keywords

Molybdenum Double-spike MC-ICP-MS Stable isotopes Reference material 

Supplementary material

216_2014_8448_MOESM1_ESM.pdf (485 kb)
ESM 1(PDF 485 kb)

Copyright information

© Springer-Verlag Berlin Heidelberg 2015

Authors and Affiliations

  1. 1.Department of Earth, Ocean and Atmospheric SciencesUniversity of British ColumbiaVancouverCanada
  2. 2.Pacific Centre for Isotopic and Geochemical Research (PCIGR), Department of Earth, Ocean and Atmospheric SciencesUniversity of British ColumbiaVancouverCanada

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