title: Ultra-low level plutonium isotopes in the NIST SRM 4355A (Peruvian Soil-1).
abstract: For more than 20 years, countries and their agencies which monitor radionuclide discharge sites and storage facilities have relied on the National Institute of Standards and Technology (NIST) Standard Reference Material (SRM) 4355 Peruvian Soil. Its low fallout contamination makes it an ideal soil blank for measurements associated with terrestrial-pathway-to-man studies. Presently, SRM 4355 is out of stock, and a new batch of the Peruvian soil is currently under development as future NIST SRM 4355A. Both environmental radioanalytical laboratories and mass spectrometry communities will benefit from the use of this SRM. The former must assess their laboratory procedural contamination and measurement detection limits by measurement of blank sample material. The Peruvian Soil is so low in anthropogenic radionuclide content that it is a suitable virtual blank. On the other hand, mass spectrometric laboratories have high sensitivity instruments that are capable of quantitative isotopic measurements at low plutonium levels in the SRM 4355 (first Peruvian Soil SRM) that provided the mass spectrometric community with the calibration, quality control, and testing material needed for methods development and legal defensibility. The quantification of the ultra-low plutonium content in the SRM 4355A was a considerable challenge for the mass spectrometric laboratories. Careful blank control and correction, isobaric interferences, instrument stability, peak assessment, and detection assessment were necessary. Furthermore, a systematic statistical evaluation of the measurement results and considerable discussions with the mass spectroscopy metrologists were needed to derive the certified values and uncertainties. The one sided upper limit of the 95% tolerance with 95% confidence for the massic (239)Pu content in SRM 4355A is estimated to be 54,000 atoms/g.
authors.affiliation: National Institute of Standards and Technology, Gaithersburg, MD, USA. kenneth.inn@nist.gov
authors.forename: Kenneth G W
authors.initials: KG
authors.lastname: Inn
authors.forename: Jerome
authors.initials: J
authors.lastname: LaRosa
authors.forename: Svetlana
authors.initials: S
authors.lastname: Nour
authors.forename: George
authors.initials: G
authors.lastname: Brooks
authors.forename: Steve
authors.initials: S
authors.lastname: LaMont
authors.forename: Rob
authors.initials: R
authors.lastname: Steiner
authors.forename: Ross
authors.initials: R
authors.lastname: Williams
authors.forename: Brad
authors.initials: B
authors.lastname: Patton
authors.forename: Debbie
authors.initials: D
authors.lastname: Bostick
authors.forename: Gregory
authors.initials: G
authors.lastname: Eiden
authors.forename: Steve
authors.initials: S
authors.lastname: Petersen
authors.forename: Matthew
authors.initials: M
authors.lastname: Douglas
authors.forename: Donna
authors.initials: D
authors.lastname: Beals
authors.forename: James
authors.initials: J
authors.lastname: Cadieux
authors.forename: Greg
authors.initials: G
authors.lastname: Hall
authors.forename: Steve
authors.initials: S
authors.lastname: Goldberg
authors.forename: Stephan
authors.initials: S
authors.lastname: Vogt
mesh_terms: D013058:Mass Spectrometry; D010568:Peru; D011005:Plutonium / Q000592:standards*; D012015:Reference Standards; D012990:Soil Pollutants, Radioactive / Q000592:standards*
chemical_list: D012990:Soil Pollutants, Radioactive; D011005:Plutonium