Multi-dimensional extractionchromatography of actinides for alpha and mass spectrometry

Abstract

A multi-dimensional (MD) separation method using extraction chromatography for the analysis of actinides in environmental samples was developed and tested for alpha spectrometry and ICP-MS. Actinides (Th, U, Np, Pu and Am) were separated into individual fractions using two resins (TEVA/DGA), after valence adjustment initially in 9 M HCl, and in the second dimension, in 3 M HNO₃, in order to remove interferences and enable their proper identification and quantification. High separation purity for Th, U, Np, Pu and Am (respectively 98, 100, 94, 98 and 99 ± 2%) were obtained. Reusability of the resins was also demonstrated (≤9). The MD separation scheme was tested on spiked soil and sediment samples as well as on certified reference material (CRM-IAEA-384) dissolved using automated lithium metaborate fusion. Results obtained for actinides by alpha spectrometry and ICP-MS were in excellent agreement with those expected (absolute relative bias: 1.9–23%) and demonstrate the complementarily of the two types of detection.