Determination of long-lived actinides in soil leachates by inductively coupled plasma: Mass spectrometry

摘要

Inductively coupled plasma -- mass spectrometry (ICP-MS) was used to concurrently determine multiple long-lived (t(sub 1/2) > 10(sup 4) y) actinide isotopes in soil samples. Ultrasonic nebulization was found to maximize instrument sensitivity. Instrument detection limits for actinides in solution ranged from 50 mBq L(sup (minus)1) ((sup 239)Pu) to 2 (mu)Bq L(sup (minus)1) ((sup 235)U) Hydride adducts of (sup 232)Th and (sup 238)U interfered with the determinations of (sup 233)U and (sup 239) Pu; thus, extraction chromatography was, used to eliminate the sample matrix, concentrate the analytes, and separate uranium from the other actinides. Alpha spectrometric determinations of (sup 230)Th, (sup 239)Pu, and the (sup 234)U/(sup 238)U activity ratio in soil leachates compared well with ICP-MS determinations; however, there were some small systematic differences (ca. 10%) between ICP-MS and a-spectrometric determinations of (sup 234)U and (sup 238)U activities.