Jump to main content
Jump to site search

Issue 11, 2009
Previous Article Next Article

Measurement of lithium isotope ratios by quadrupole-ICP-MS: application to seawater and natural carbonates

Author affiliations

Abstract

We present an improved method for lithium isotope ratio (7Li/6Li) determinations with low total lithium consumption (<0.2 ng/quintuplicate analyses), high column yields (>99.98%), high isotope ratio precision (<±0.8‰, 2σ), and low blanks (1.0 ± 0.5 pg). We refine a single step ion chromatographic method to quantitatively recover and separate lithium from all matrix elements using small volume resin (2 ml/3.4 meq AG 50W-X8) and low volume elution (6 ml, 0.5 N HCl) with low procedural blanks (<500 fg/ml). We optimize the procedure for analyses of natural carbonates (foraminifera) containing 1 to 2 ppm lithium. This lithium separation method is applicable to other natural samples (e.g. seawater, pore-waters, mineral grains) by appropriate scaling. Isotope ratio measurements are made by a single collector Quadrupole ICP-MS (Agilent 7500cs) using cool plasma (600 W), soft extraction, peak jumping, and pulse detection mode with sample-standard bracketing. The precision is better than ±0.8‰ (2σ) for L-SVEC lithium standards and better than ±1.5‰ (2σ) for natural samples. We report a high matrix tolerance limit for sodium (∼0.6 mol/mol, Li/Na) and calcium (<20 µmol/mol, Li/Ca) for our Quadrupole ICP-MS method. Our seawater δ7Li value (30.75 ± 0.41‰, 2σ, n = 10) is the same as that reported by other workers (∼31.0 ± 0.5‰). Species-specific and bulk sample δ7Li analyses of two size fractions of core-top foraminifera yield values similar to modern seawater.

Graphical abstract: Measurement of lithium isotope ratios by quadrupole-ICP-MS: application to seawater and natural carbonates

Back to tab navigation

Supplementary files

Publication details

The article was received on 09 Apr 2009, accepted on 06 Aug 2009 and first published on 10 Sep 2009


Article type: Paper
DOI: 10.1039/B907122A
Citation: J. Anal. At. Spectrom., 2009,24, 1524-1533
  •   Request permissions

    Measurement of lithium isotope ratios by quadrupole-ICP-MS: application to seawater and natural carbonates

    S. Misra and P. N. Froelich, J. Anal. At. Spectrom., 2009, 24, 1524
    DOI: 10.1039/B907122A

Search articles by author

Spotlight

Advertisements