Significance and Use
This practice may be used as part of a bioassay program for workers potentially exposed to nuclear material by measuring 237Np, 232Th and 235U and 238U in their urine samples. ICP-MS has been used to analyze for many actinides in high-level radioactive wastes (1) , in soils (2) as well as uranium in urine (Test Method C1379). 237Np and 239Pu analysis by ICP-MS in bioassay samples has also been reported (3).
Several days counting times are required for alpha-particle analysis of 237Np, 232Th and 235U and 238U whereas ICP-MS requires only four minutes per sample. Alpha-particle counting methods for neptunium may also require the use of 239Pu as a radiotracer for determination of chemical yield.
ICP-MS sensitivity limits and isobaric interferences preclude accurate determination of 239Pu, 241Am and 234U at levels present in the urine samples. 234U may be estimated from the 235U: 238U ratio by inference.
1.1 This practice covers the separation and preconcentration of neptunium-237 (237Np), thorium-232 (232Th), uranium-235 (235U) and uranium-238 (238U) from urine followed by quantitation using ICP-MS.
1.2 This practice can be used to support routine bioassay programs. The minimum detectable concentrations (MDC) for this method, taking the preconcentration factor into account, are approximately 1E-2Bq for 237Np (0.38ng), 2E-6Bq for 232Th (0.50ng), 4E-5Bq for 235U (0.50ng) and 6E-6Bq for 238U (0.48ng).
1.3 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.
C859 Terminology Relating to Nuclear Materials
C1379 Test Method for Analysis of Urine for Uranium-235 and Uranium-238 Isotopes by Inductively Coupled Plasma-Mass Spectrometry
C1475 Guide for Determination of Neptunium-237 in Soil
D1193 Specification for Reagent Water
D4962 Practice for NaI(Tl) Gamma-Ray Spectrometry of Water
Bioassay; urine; neptunium; thorium; uranium; mass; inductively coupled plasma-mass spectrometry; gamma-ray spectrometry; isotope ratio; isotope dilution; extraction chromatography; Bioassay; Extraction chromatography; Gamma-ray spectrometry; ICP-MS (inductively-coupled plasma-mass spectrometry); Neptunium-237; Thorium-232 content; Uranium-235; Urine ;
ICS Number Code 71.040.50 (Physicochemical methods of analysis)
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