Lithium, magnesium and sulfur purification from seawater using an ion chromatograph with a fraction collector system for stable isotope measurements

Toshihiro Yoshimura; Daisuke Araoka; Yusuke Tamenori; Junichiro Kuroda; Hodaka Kawahata; Naohiko Ohkouchi

doi:10.1016/j.chroma.2017.11.052

Lithium, magnesium and sulfur purification from seawater using an ion chromatograph with a fraction collector system for stable isotope measurements

J Chromatogr A. 2018 Jan 5:1531:157-162. doi: 10.1016/j.chroma.2017.11.052. Epub 2017 Nov 24.

Authors

Toshihiro Yoshimura¹, Daisuke Araoka², Yusuke Tamenori³, Junichiro Kuroda⁴, Hodaka Kawahata⁵, Naohiko Ohkouchi⁶

Affiliations

¹ Department of Biogeochemistry, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15, Natsushima, Yokosuka 237-0061, Japan; Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8564, Japan. Electronic address: yoshimurat@jamstec.go.jp.
² Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology, Tsukuba Central 7, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8567, Japan.
³ Japan Synchrotron Radiation Research Institute/SPring-8, 1-1-1 Kouto, Sayo, Hyogo 679-5198, Japan.
⁴ Department of Biogeochemistry, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15, Natsushima, Yokosuka 237-0061, Japan; Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8564, Japan.
⁵ Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8564, Japan.
⁶ Department of Biogeochemistry, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15, Natsushima, Yokosuka 237-0061, Japan.

PMID: 29198448
DOI: 10.1016/j.chroma.2017.11.052

Abstract

We describe the mass descrimination and validation of an offline method for purification of Li, Mg and S with an ion chromatograph coupled to an automated fraction collector for use prior to stable isotope measurements. Significant sub-fraction mass fractionation was observed for both the Li and the Mg stable isotope ratios. The lighter Li and heavier Mg isotopes were preferentially retained by the column, resulting in ⁷Li/⁶Li and ²⁶Mg/²⁴Mg biases up to 85.8‰ and 0.95‰, respectively. The isotopic compositions of Li, Mg, and S separated from seawater were δ⁷Li_L-SVEC = +30.9‰, δ²⁶Mg_DSM3 = -0.83 ± 0.10‰, and δ³⁴S_VCDT = +19.4 ± 0.6‰; each chromatographic peak was completely recovered, and the results were in good agreement with the published values regardless of whether or not chemical suppressor was used. The purification method enables multi-isotope analysis of a sample using various mass spectrometry techniques, such as multiple-collector inductively coupled plasma and thermal ionization mass spectrometry.

Keywords: Fraction collector; Ion chromatograph; Mass fractionation; Stable isotope ratio.

MeSH terms

Chromatography, Ion Exchange*
Isotope Labeling
Lithium / isolation & purification*
Magnesium / isolation & purification*
Seawater / chemistry*
Sulfur / isolation & purification*

Substances

Sulfur
Lithium
Magnesium