Determination of polonium-210 in environmental samples using diglycolamide-based cloud point extraction coupled to alpha spectrometry analysis

Guillaume Blanchet-Chouinard; Dominic Larivière

doi:10.1016/j.apradiso.2020.109549

Determination of polonium-210 in environmental samples using diglycolamide-based cloud point extraction coupled to alpha spectrometry analysis

Appl Radiat Isot. 2021 Feb:168:109549. doi: 10.1016/j.apradiso.2020.109549. Epub 2020 Dec 4.

Authors

Guillaume Blanchet-Chouinard¹, Dominic Larivière²

Affiliations

¹ Laboratoire de radioécologie, Département de chimie, Université Laval, 1045 Avenue de la Médecine, Québec, QC, G1V 0A6, Canada.
² Laboratoire de radioécologie, Département de chimie, Université Laval, 1045 Avenue de la Médecine, Québec, QC, G1V 0A6, Canada. Electronic address: dominic.lariviere@chm.ulaval.ca.

PMID: 33307441
DOI: 10.1016/j.apradiso.2020.109549

Abstract

This study presents a novel cloud point extraction (CPE) methodology for the separation and enrichment of polonium-210 prior to alpha-spectrometric quantification in water, urine and digested samples. The extractive behaviour of diglycolamide-based ligands towards Po by CPE was determined and optimised in various acidic conditions. The extraction efficiency and selectivity of the CPE systems depend greatly on the choice of the extracting agent and acidic conditions. The thorough optimisation of those specific parameters has led to the development of a suitable cloud point extraction system for the determination of polonium-210 at ultra-trace levels compatible with alpha-spectrometry. To facilitate this coupling, a back-extraction procedure was optimised and performed on the surfactant-rich phase to enable the spontaneous deposition of polonium-210 onto a silver disk; this also avoids making the matrix transfer step mandatory due to the presence of a nitric medium. Method detection and quantification limits of 3.5 and 12 mBq L^-1, respectively, were determined by alpha spectrometry. The robustness of the proposed methodology was demonstrated by the determination of polonium ions concentration in various environmental and biological samples and solid certified reference materials.

Keywords: Alpha spectrometry; Ammonium citrate back-extraction; Cloud point extraction; Diglycolamide analogs; Polonium-210; Preconcentration; Spontaneous deposition.