PRECONCENTRATION OF ACTINIDE ELEMENTS FROM SOILS AND LARGE-VOLUME WATER SAMPLES USING EXTRACTION CHROMATOGRAPHY

?he analysis of environmental samples for low levels of U, Pu, Am and other actinide elements is often hampered by sample dependent problems involving the composition and/or mineralogy of specific samples. Whil e relatively small samples (1-2 g of soil or 1-21 of water) are requir ed to reach the extremely low detection limits occasionally mandated f or environmental monitoring. One approach to avoid the troublesome and often inexplicable problems collectively referred to as ''matrix effe cts'' is to pre-concentrate actinides into a common form that would th en behave uniformly and predictably during a subsequent separation sch eme. Recently, a new extraction chromatographic resin based on diphosp honate chemistry was developed at Argonne National Laboratory. This re sin commercialized as Eichrom's Actinide Resin, exhibits extremely hig h affinity for actinide elements even in the presence of high concentr ations of salts. We have measured the uptake of actinides by the Dipex (R) extractant from natural waters and natural matrix soil standards. Water samples have been analyzed for gross alpha-activities and gave r esults that compared favorably to the traditional approach. In additio n, we have obtained good recoveries and excellent separations for soil samples as judged by resolution on the alpha-spectra and the complete absence of interfering energies.