Separation of actinides from a bone ash matrix with extraction chromatography

A method based on extraction chromatography for the separation of actinides from bone ash has been developed and tested. Group separation of Th, U, Pu and Am from the sample matrix, and, e.g. Sr, was done with a TRU Resin 'trade mark' column. The sequential separation of the actinides was performed with UTEVA Resin 'trade mark' and TRU Resin 'trade mark' columns. The mean recoveries for the bone ash analyses were 78±2, 86±5, 81±5 and 76±4% (1 s) for Th, U, Pu and Am, respectively. The activity levels were 1 mBq g-1 of sample for Th,U and Pu and 10 mBq g-1 of sample for Am. The different actinide fractions were pure and the peak resolution in the α spectra was sufficient. Sample sizes ranged from 3 to 5 g. The problems caused by the loss of the organic extractant from the columns during the elution of Th and Am with 4-9 M HCl was eliminated completely by decomposition of the organic residues using strong mineral acids, HNO3, HCl, HF and/or HClO4, before the sample preparation. The separation method is simple and faster than traditional methods based on anion exchange and liquid-liquid extraction. Less strong acid and organic wastes are produced. Strontium-90 concentrations can be analysed from the same sample as the actinides, which saves time and lowers the detection limits when the quantity of sample material is limited. (orig.)