Accuracy and precision of (238)Pu determination at fg level by alpha spectrometry using (239)Pu and (240)Pu amount analyzed by ICP-MS

• Published in: Applied radiation and isotopes 2010-12, Vol.68 (12), p.2147-2152
• Main Authors: Mácsik, Zsuzsanna, Shinonaga, Taeko
• Format: Article
• Language: English
• Subjects: Mass Spectrometry - methods; Plutonium - chemistry; Reproducibility of Results
• ISSN: 1872-9800
• DOI: 10.1016/j.apradiso.2010.07.006

The accuracy and precision of the determination of (238)Pu amount at the fg (mBq) level by a combination of alpha spectrometry and inductively coupled plasma mass spectrometry (ICP-MS) were studied using a standard reference material (CRM 137-Plutonium [corrected] Isotopic Standard, National Bureau of Standards, Washington, D.C., USA). The activity of (238)Pu was calculated from the amount of (239)Pu and (240)Pu obtained by isotope dilution method and ICP-MS combined with the intensity ratio of (238)Pu/(239,240)Pu obtained by alpha spectrometry without adding spike. The results show that approximately 130 fg of (238)Pu can be analyzed within an accuracy of 7% bias and with 5-12% of total uncertainty. The examined analytical procedure was applied to the quantitative analysis of (238)Pu in water samples representing Safeguards inspection samples. The combination of alpha spectrometry and ICP-MS is useful for quantitative and isotopic analysis in low-level Pu samples. Also the method leads to improving the accuracy of (238)Pu determination because efficiency calibration is not necessary for alpha spectrometry.