Determination of plutonium and its isotopic ratio in marine sediment samples using quadrupole ICP-MS with the shield torch system under normal plasma conditions

• Published in: Analytical and bioanalytical chemistry 2004-06, Vol.379 (3), p.532-539
• Main Authors: Zheng, Jian, Yamada, Masatoshi, Wang, Zhongliang, Aono, Tatsuo, Kusakabe, Masashi
• Format: Article
• Language: English
• Subjects: Environmental Monitoring - methods; Geologic Sediments - chemistry; Japan; Plutonium - analysis; Radioisotopes; Spectrophotometry, Atomic - methods; Water Pollutants, Radioactive - analysis
• ISSN: 1618-2642; 1618-2650
• DOI: 10.1007/s00216-004-2626-x

An analytical method for determining (239)Pu and (240)Pu in marine sediment samples, which uses quadrupole ICP-MS, was developed in this work. A simple anion-exchange chromatography system was employed for the separation and purification of Pu from the sample matrix. A sufficient decontamination factor of 1.4 x 10(4) for U, which interferes with the determination of (239)Pu, was achieved. High sensitivity Pu determination was obtained, which led to an extremely low concentration detection limit of approximately 8 fg/ml (0.019 mBq/ml for (239)Pu; 0.071 mBq/ml for (240)Pu) in a sample solution, or an absolute detection limit of 42 fg in a 5 ml sample solution, by using the shield torch technique. Analytical results for the determination of the (239+240)Pu and the (240)Pu/(239)Pu ratio in IAEA 368 (ocean sediment) reference material indicated that the accuracy of the method was satisfactory. The method developed was successfully applied to a study of Pu behavior in the sediments from Sagami Bay, Japan. The observed high (240)Pu/(239)Pu ratio in the sediment core indicated that there was additional Pu input derived from close-in fallout in addition to the global fallout.