Analysis of plutonium in soil samples

Procedures for analysis of plutonium in soil samples were developed using a nion exchange as a purification technique. Special attention was paid to re moving impurities of Th-228 which interferes in Pu-238 determination by alp ha spectrometry. Two anion-exchange methods were compared. The determinatio n of plutonium in soil involves the conversion of soil samples to acid-solu ble form. Two methods for the extraction of plutonium from a natural refere nce soil were compared. The first method (a direct digestion in nitric acid ) is suitable for the determination of plutonium in large amounts of sample . The second method involves microwave digestion of soil (5 g) with a mixtu re of HNO3, HCl and HF, and is suitable for saving time in routine determin ations. Activities calculated with a reference soil matrix were in good agr eement with the reference value. The microwave digestion method was applied in a study of different soil samples, and recoveries ranged between 20% an d 50%. (C) 2000 Elsevier Science Ltd. All rights reserved.