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Simultaneous determination of {sup 237}Np, {sup 232}Th and U isotopes in urine samples using extraction chromatography, ICP-MS and gamma-ray spectroscopy

Journal Article · · Radioactivity and Radiochemistry
OSTI ID:390909
; ; ;  [1]
  1. Lawrence Livermore National Lab., CA (United States)

Simultaneous determination of {sup 237}Np, {sup 232}Th and U isotopes has been demonstrated using extraction chromatographic sample preparation in conjunction with inductively coupled plasma mass spectrometry (ICP-MS). After being spiked with {sup 239}Np, {sup 233}U, and {sup 230}Th tracers, urine samples were wet ashed with HNO{sub 3} and loaded onto an extraction chromatographic column. Following elution, samples were spiked with a known quantity of {sup 242}Pu and brought to a constant volume. The quantities of {sup 232}Th and U in the original sample were then determined using isotopic dilution techniques. Similarly, the isotopic composition of the U was determined by measurements of the {sup 235}U/{sup 238}U isotopic ratio. The quantity of {sup 237}Np in the sample was determined using a set of external standards as well as measurements of the chemical yield (recovery) of the Np, which were determined by gamma-ray counting of the short-lived {sup 239}Np tracer. Direct comparison of the chemical recovery for Np in a set of spiked urine samples, as determined by gamma-ray counting and ICP-MS, were in good agreement with one another ({plus_minus}3%) and indicated that Np is recovered with good yield (85-90%). Uranium and Th isotopes were typically recovered from the cleanup procedure with efficiencies of 75-85%. The detection limits of {sup 237}Np, {sup 232}Th, {sup 235}U and {sup 238}U in a 50-mL using sample were approximately 8E-4dpm, 1E-7 dpm, 2E-6 dpm, 4E-7 dpm, respectively, for a one-minute data-acquisition cycle employing a conventional pneumatic nebulizer.

DOE Contract Number:
W-7405-ENG-48
OSTI ID:
390909
Journal Information:
Radioactivity and Radiochemistry, Journal Name: Radioactivity and Radiochemistry Journal Issue: 3 Vol. 7; ISSN RARAE6; ISSN 1045-845X
Country of Publication:
United States
Language:
English