Selenium extraction: development on extraction chromatographic resins compatible with Diffusive Gradient in Thin film (DGT)
Abstract
Measurement of Selenium is of importance regarding public health as the ratio between beneficial daily intake and toxicity is rather low [1], [2]. Also from the radiological perspective, Se-79 as a long-lived fission nuclide (T1/2=2.8x105y) with high mobility in environment, is of concern regarding waste management and decommissioning [3], [4].
Due to the existence of different oxidation states Selenium has a complex speciation chemistry which makes extraction and separation schemes not straightforward. The aim of this research is to develop extraction methods for Selenium based on extraction chromatographic resins allowing for the extraction of Se(VI), as well as Se(IV), from water samples for later use on DGT (Diffusive Gradients in Thin films) devices.
Extraction chromatographic resins have been tested and characterized for Se and other elements. For Se(VI) a commercially available Aliquat 336 based extraction chromatographic resin (TEVA resin[5]) was found to be most suitable, for Se(IV) a newly developed extraction chromatographic resin based on Piazselenol chemistry was found to be most effective, data on the selectivity of this resin will be presented. The extraction of Se (IV) and Se (VI) by these resins was tested on water sampled in Lille City, where a high Se spatial variability has been observed. Concentrations in groundwater can reach 30 µg/L As a consequence; most Se-contaminated wells are no longer exploited by the water operators.
One of the applications of this development is to be able to measure Se concentrations insitu in contaminated areas including very complex object such as hyporheic zone.
[1] Cary L. et al. Applied Geochemistry 48 (2014) 70–82
[2] Chen C. et al. Biological Trace Element Research Vols. 71-72 (1999) 131-138
[3] http://www.irsn.fr/FR/Larecherche/publications-documentation/fiches-radionucleides/Documents/environnement/Selenium_Se79_v2.pdf last access 03/03/2016
[4] Uchida et al. WM2009 Conference, March 1-5, 2009, Phoenix, AZ
[5] Horwitz P. et al. Analytica Chimica Acta 310 (1995) 63-78