A simultaneous analytical method for sequential separation and determination of actinides and 90Sr in large-size environmental samples has been developed. In this method, successive co-precipitation steps were firstly conducted to remove matrix elements, then sequential column separation method was applied for simultaneous separation and purification of actinides and 90Sr/90Y. By using vacuum box technology, the total analytical time was minimized and batch processing allowed analyzing 12 samples in four days. The activity of 90Sr was obtained immediately by measuring its daughter radionuclide (90Y) with triple-to-double coincidence ratio (TDCR) Cherenkov counting, while the concentrations of Pu isotopes and 241Am could be measured by alpha spectrometry and mass spectrometric techniques. The overall recoveries of Pu, Am, Sr and Y were higher than 70% for the entire procedure, while the recovery ratios of Sr/Y were between 0.95 and 1.04 before chromatographic separation. The developed method was verified using 20 g and 50 g of environmental soil samples spiked with certified reference materials IAEA-384 or IAEA-385 and standard solution of 90Sr/90Y, and good agreement between the expected values and measured results has been achieved.
Keywords: (90)Sr; Actinides; ICP-MS; Large-size soil; Sequential separation; TDCR Cherenkov measurement.
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