Rapid sequential determination of americium and plutonium in sediment and soil samples by ICP-SFMS and alpha-spectrometry

Abstract

An improved sample preparation method for the determination of americium and plutonium in sediment and soil samples by inductively coupled plasma sector field mass spectrometry (ICP-SFMS) and alpha-spectrometry is described. The developed procedure involves a selective CaF2 co-precipitation for pre-concentration and matrix removal followed by a sequential extraction chromatographic separation. The average chemical recovery of sample preparation was between 81–94% for both americium and plutonium. The method development also focused on the elimination of possible interferences in mass spectrometric analysis caused by molecular ions (e.g. 238U 1H+, 204Pb 36Ar+ or 208Pb 16O2 +) employing the suitable matrix separation prior to ICP-SFMS analysis coupled with a desolvation sample introduction system. For 239Pu, 240Pu, 241Pu and 241Am limits of detection of 15, 9.2, 14 and 23 fg g-1 was achieved by ICP-SFMS, respectively. The applied sample preparation and measurement can be carried out within 6 h for one batch of samples. Results of certified reference materials (IAEA-384 and IAEA-385) analysed by the two different measurement techniques agreed well with the recommended or information values.