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Pre-concentration of thorium and neodymium isotopes using Nobias chelating resin: method development and application to chromatographic separation

Citation

Perez-Tribouillier, H and Noble, TL and Townsend, AT and Bowie, AR and Chase, Z, Pre-concentration of thorium and neodymium isotopes using Nobias chelating resin: method development and application to chromatographic separation, Talanta, 202 pp. 600-609. ISSN 0039-9140 (2019) [Refereed Article]

Copyright Statement

2019 Elsevier B.V. All rights reserved.

DOI: doi:10.1016/j.talanta.2019.03.086

Abstract

The isotopes of thorium (Th) and neodymium (Nd) are used as tracers in oceanography, and are key parameters in the international GEOTRACES program. The very low concentrations of Th and Nd as well as the reactive nature of Th isotopes makes the analysis of seawater samples a complex process. Analysis requires time-consuming pre-concentration from over 5 L of seawater. We describe a method to simultaneously pre-concentrate dissolved Th and Nd from acidified seawater samples using the Nobias PA1L chelating resin. Prior to pre-concentration, hydrofluoric acid is added to the sample to stabilise Th, ammonium acetate buffer added (0.05 M), pH adjusted to 4.75, and then finally the prepared sample is pumped through the Nobias resin at a rate of 15 ml min−1. Up to 6 samples can be processed simultaneously. Following elution in 3 M HNO3, both elements are chromatographically separated and determined using Inductively Coupled Plasma Mass Spectrometry. Oxidation of the sample between all column separation steps, including after the initial Nobias resin, is important for obtaining maximum elemental recoveries. The method has >90% recovery with blank levels typically <10 pg for 232Th and <70 pg for Nd. Accuracy is excellent, as our reported values generally agree within 1% of the GEOTRACES intercalibration standards. The long-term analysis of these materials also indicates excellent reproducibility. The pre-concentration of Th and Nd using the Nobias resin is a time saving option compared to the widely used iron co-precipitation technique. Sample handling is also reduced, decreasing the risk of sample contamination. The simplicity of our suggested pre-concentration procedure makes it possible to be applied at sea.

Item Details

Item Type:Refereed Article
Keywords:thorium, neodymium isotopes, Nobias chelating resin, pre-concentration, seawater, chromatographic separation, GEOTRACES
Research Division:Earth Sciences
Research Group:Geochemistry
Research Field:Isotope Geochemistry
Objective Division:Environment
Objective Group:Physical and Chemical Conditions of Water
Objective Field:Physical and Chemical Conditions of Water in Marine Environments
UTAS Author:Perez-Tribouillier, H (Mr Habacuc Perez-Tribouillier)
UTAS Author:Noble, TL (Dr Taryn Noble)
UTAS Author:Townsend, AT (Associate Professor Ashley Townsend)
UTAS Author:Bowie, AR (Professor Andrew Bowie)
UTAS Author:Chase, Z (Associate Professor Zanna Chase)
ID Code:133885
Year Published:2019
Funding Support:Australian Research Council (DP150100345)
Deposited By:Oceans and Cryosphere
Deposited On:2019-07-12
Last Modified:2019-09-26
Downloads:0

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