High-precision determination of lithium and magnesium isotopes utilising single column separation and multi-collector inductively coupled plasma mass spectrometry

Bohlin, Madeleine S and Misra, Sambuddha and Lloyd, Nicholas and Elderfield, Henry and Bickle, Mike J (2018) High-precision determination of lithium and magnesium isotopes utilising single column separation and multi-collector inductively coupled plasma mass spectrometry. In: RAPID COMMUNICATIONS IN MASS SPECTROMETRY, 32 (2). pp. 93-104.

PDF Rap_Com_Mas_32-2_93_2018.pdf - Published Version Restricted to Registered users only Download (692kB) | Request a copy

Abstract

RationaleLi and Mg isotopes are increasingly used as a combined tool within the geosciences. However, established methods require separate sample purification protocols utilising several column separation procedures. This study presents a single-step cation-exchange method for quantitative separation of trace levels of Li and Mg from multiple sample matrices. MethodsThe column method utilises the macro-porous AGMP-50 resin and a high-aspect ratio column, allowing quantitative separation of Li and Mg from natural waters, sediments, rocks and carbonate matrices following the same elution protocol. High-precision isotope determination was conducted by multi-collector inductively coupled plasma mass spectrometry (MC-ICPMS) on the Thermo Scientific NEPTUNE Plus fitted with 10(13) amplifiers which allow accurate and precise measurements at ion beams 0.51V. ResultsSub-nanogram Li samples (0.3-0.5ng) were regularly separated (yielding Mg masses of 1-70g) using the presented column method. The total sample consumption during isotopic analysis is <0.5ng Li and <115ng Mg with long-term external 2 sigma precisions of 0.39 parts per thousand for Li-7 and +/- 0.07 parts per thousand for Mg-26. The results for geological reference standards and seawater analysed by our method are in excellent agreement with published values despite the order of magnitude lower sample consumption. ConclusionsThe possibility of eluting small sample masses and the low analytical sample consumption make this method ideal for samples of limited mass or low Li concentration, such as foraminifera, mineral separates or dilute river waters.

Item Type:	Journal Article
Publication:	RAPID COMMUNICATIONS IN MASS SPECTROMETRY
Publisher:	10.1002/rcm.8020
Additional Information:	Copy right for this article belongs to the WILEY, 111 RIVER ST, HOBOKEN 07030-5774, NJ USA
Department/Centre:	Division of Mechanical Sciences > Centre for Earth Sciences
Date Deposited:	20 Jan 2018 06:55
Last Modified:	20 Jan 2018 06:55
URI:	http://eprints.iisc.ac.in/id/eprint/58803

Actions (login required)

View Item