Methodology: Strontium Isotope Analysis

Extraction chromatography followed by analysis on a multi-collector–inductively coupled plasma–mass spectrometer (MC-ICP-MS) is a very efficient method for routine high-precision isotope and elemental analyses of strontium. Pairing the MC-ICP-MS with a laser ablation system (LA-MC-ICP-MS) can provide high-resolution in situ elemental/isotopic compositions of solid samples (>5 mm for profile analysis) with more efficiency and lower sample consumption. Application of LA-MC-ICP-MS not only increases the analytical efficiency but also reduces the sample size and avoids complications associated with sample digestion. 

Analytical Method

Strontium purification: Strontium is separated from the matrix elements by means of extraction chromatography using Eichrom Sr-specific cation exchange resin following the methods of Pourmand and Dauphas (2010) and Pourmand et al. (2014). 

Strontium isotope analysis: Strontium isotope measurements are performed with a Neptune Plus multi-collection inductively coupled plasma mass spectrometer (MC-ICP-MS) following the method in Pourmand et al., 2014. 

Sample Requirements

The 87Sr/86Sr ratio can be measured in various sample types such as bone/teeth, water, corals and foraminifera, carbonate rocks, igneous and metamorphic rocks, mineral dust, plants and tissues, and hair. The sample size for Sr isotopic measurements varies from 10 to 1000 mg and 1 to 100 ml for solid and water samples, respectively, depending on the concentration of Sr in the sample.

For more information on Samples Type and Selection 

References

Anne E. Barkley, Joseph M. Prospero, Natalie Mahowald, Douglas S. Hamilton, Kimberly J. Popendorf, Amanda M. Oehlert, Ali Pourmand, Alexandre Gatineau, Kathy Panechou-Pulcherie, Patricia Blackwelder, and Cassandra J. Gaston, 2019: African biomass burning is a substantial source of phosphorus deposition to the Amazon, Tropical Atlantic Ocean, and Southern Ocean. Proceedings of the National Academy of Sciences (PANS), DOI 10.1073/pnas.1906091116.

Michèlle van der Does, Ali Pourmand, Arash Sharifi, Jan-Berend Stuut, 2018: North African mineral dust across the tropical Atlantic Ocean: Insights from dust particle size, radiogenic Sr-Nd-Hf isotopes and rare earth elements (REE). Aeolian Research, vol. 33, pp.106-116, DOI 10.1016/j.aeolia.2018.06.001.

Sharifi, A.; Murphy, L. N.; Pourmand, A.; Clement, A. C.; Canuel, E. A.; Naderi Beni, A.; Lahijani, H. A. K. and Ahmady-Birgani, H., 2018:Early Holocene Greening of the Afro-Asian Dust Belt Changed Sources of Mineral Dust in West Asia. Earth and Planetary Science Letters, Volume 481, pp.30-40, DOI 10.1016/j.epsl.2017.10.001.

Pourmand, A.; Prospero, J. M. and Sharifi, A., 2014: Geochemical fingerprinting of trans-Atlantic African dust based on radiogenic Sr-Nd-Hf isotopes and rare earth element anomalies. GEOLOGY, vol.42, pp.675-678. 

Pourmand, A. and Dauphas, N., 2010. Distribution coefficients of 60 elements on TODGA resin: 28 Application to Ca, Lu, Hf, U and Th isotope geochemistry. Talanta 81, 741-753.