Authors:M. Pham, M. Betti, P. Povinec, V. Alfimov, D. Biddulph, J. Gastaud, W. Kieser, J. López Gutiérrez, G. Possnert, J. Sanchez-Cabeza, and T. Suzuki
A certified reference material designed for the determination of 129I in seawater, IAEA-418 (Mediterranean Sea water) is described and the results of certification are presented. The median
of 129I concentration with 95% confidence interval was chosen as the most reliable estimates of the true value. The median, given
as the certified value, is 2.28 × 108 atom L−1 (95% confidence interval is (2.16–2.73) 108 atom L−1), or 3.19 × 10−7 Bq L−1 (95% confidence interval is (3.02–3.82) × 10−7 Bq L−1). The material is intended to be used for standardization procedures applied in accelerator mass spectrometric laboratories.
It is available in 1 L units and may be ordered via IAEA web side (www.iaea.org).
Authors:F. S. Tagliaferro, E. A. De Nadai Fernandes, and M. A. Bacchi
A random sampling was carried out in the coffee beans collected for the preparation of the organic green coffee reference
material in view of assessing the homogeneity and the presence of soil as impurity. Fifteen samples were taken for the between-sample
homogeneity evaluation. One of the samples was selected and 10 test portions withdrawn for the within-sample homogeneity evaluation.
Br, Ca, Co, Cs, Fe, K, Na, Rb, Sc and Zn were determined by instrumental neutron activation analysis (INAA). The F-test demonstrated that the material is homogeneous for Ca, Co, Cs, K and Sc, but not homogeneous for Br, Fe, Na, Rb and Zn.
Results of terrigenous elements suggested negligible soil contamination in the raw material.
Elemental concentrations of twelve geochemical reference materials of ores and mineralized rocks were determined including
some for which there were few previously published data. Reference materials CHR-Bkg, CHR-Pt, CCU-1c, NBM-1a, NBM-2a, NBM-4a,
NBM-6a, NBM-6b, PM-S, UMT-1, WMG-1, and WMS-1 were analyzed for 34 elements by instrumental neutron activation. To our knowledge,
the analytical results in this paper are among the first published for five reference materials from the Nevada Bureau of
Mines and Geology. Reliable results for Au and Ir down to concentrations of a few ng.g-1were obtained without preconcentration.
In order to determine the elemental concentrations of three new soil standard reference materials SRMs 2709, 2710 and 2711 from the National Institute of Standards and Technology (NIST), a comparative study of different medium-lived neutron activation analysis methods was carefully performed. Three irradiation conditions (1-hour thermal, 1-hour epithermal and 5-minute epithermal) and two counting modes (normal and Compton suppression) have been evaluated for following ten elements: As, Au, Cd, Ga, K, La, Mo, Sb, Sm, and W. The results show that the method of 5-minute epithermal and a 1-day decay is the optimum way to analyze Ga, while the addition of the Compton suppression is very beneficial for the determination of K. Using the Compton suppression system in conjunction with the 1-hour epithermal and a 1-week decay, is ideal to determine Au, Cd, Mo and W, while routine 1-hour thermal and a 1-week decay, is adequate to determine As, Sb, Sm and La in concentrations found in soil.
The instrumental neutron activation analysis technique (INAA) was used for homogeneity tests and certification analyses of coal fly ash reference materials ENO, ECH, and EOP prepared at the Institute of Radioecology and Nuclear Techniques (IRANT), Koice, Czechoslovakia. Quantitative estimation of a degree of inhomogeneity was suggested. The relative standard deviations due to inhomogeneity were found to be <1% for macroconstituents and <3% for minor and trace elements for sample weights about 25 mg. The results of determination of the elements Al, As, Ba, Ca, Ce, Co, Cr, Cs, Dy, Eu, Fe, Ga, Hf, In, K, La, Mn, Na, Nd, Ni, Rb, Sb, Sc, Sm, Sr, Ta, Th, Ti, U, V, W, and Zn were compared with the IRANT certified or information values. NBS SRM 1633a Trace Elements in Coal Fly Ash was also analyzed as a control sample and the results for the above elements were compared with the NBS certified, information or literature available values. From these comparisons, inference was made on the quality of the IRANT specified values for the element contents.
In order to calibrate a gamma-ray spectrometer for radioactivity measurements in environmental samples, it is essential to
use standard radioactive sources in the appropriate geometrical configuration. However, the lack of standard sample due to
any reason would necessitate the use of reference materials as reliable alternative. They often appear in many matrices and
densities. Accordingly, special attention should be drawn towards optimizing the calibration. This work studies the errors
encountered because of the attenuation process due to the density difference of the samples (including reference samples)
aliquots with identical matrix contents. The highest effect was noticed in the lower energy regions. This study suggests that
even for the reference samples with the same matrix, it is necessary to set a recommended density for the measurement process
to avoid the errors due to the attenuation. If this is not practically possible it is recommended that attenuation correction
due to matrix contents followed by another correction due to density correction would be a reliable approach to reach an optimum
Authors:R. Jaćimović, B. Smodiš, T. Bučar, and P. Stegnar
A suite of natural matrix reference materials (RMs) were used to assess the quality of analytical results obtained by k0-instrumental neutron activation analysis (k0-INAA) at the Joef Stefan Institute (IJS). Five certified reference materials (CRMs) from the Institute for Reference Materials and Measurements (IRMM), two standard reference materials (SRMs) from the National Institute of Standards and Technology (NIST), three RMs from the International Atomic Energy Agency (IAEA) and one RM from IJS were analyzed. Altogether, results for twenty-four elements in inorganic matrices and twenty-nine elements in organic matrices, obtained by k0-INAA, were compared to certified values. Results obtained show good agreement with certified or assigned values except for Fe, La, Nd, Sm and U in inorganic matrices, and Ag, Al and Cr in organic matrices.
Authors:C. Machado, S. Maria, M. Saiki, and A. Figueiredo
Instrumental neutron activation analysis was applied to determine La, Ce, Nd, Sm, Eu, Tb, Yb, Lu and Sc in two biological
reference materials: NIST 1575 Pine Needles and BCR-CRM 101 Spruce Needles. The purpose was to contribute to the reference
data for these two reference materials. The results were obtained with a good precision (relative standard deviations less
than 15%). For the Pine Needles reference material there are already some proposed values and our results showed, in general,
a good agreement with the data published. The contribution of uranium fission products to La, Ce, Nd and Sm was evaluated
and considered in the determination of these elements. Interferences in the determination of rare earth elements in biological
materials are also discussed.
Referencematerials of known properties are commonly used to calibrate, verify, or validate the performance of test instruments or methods. In dynamic mechanical analysis, spring steel is commonly used to calibrate
The paper describes a method of radioactivation analysis for the determination of indium, copper and nickel. In the determination
of indium, ordinary and displacement substoichiometries were applied for glassmaking materials while ordinary substoichiometry
was applied for NBS standard reference materials. Copper and nickel in glassmaking materials and NBS standard reference materials
were also determined by the displacement and ordinary substoichiometries. Indium contents in glassmaking materials by the
two methods agreed with each other. The analytical results of indium, copper and nickel in NBS' SRM were also in good agreement
with published values and certified values by NBS.