Non-destructive neutron activation analysis was employed to determine zinc in ten biological standard reference materials from the National Bureau of Standards and the National Research Council of Canada. The use of a 4 h. irradiation at a medium neutron flux allows excellent accuracies, precision and sensitivities to be attained for all the samples analyzed. It is suggested that neutron activation analysis be one of the benchmark methods for the determination of zinc in biological reference materials for concentrations as low as the one part per million level.
Authors:M. Wasim, A. Rahman, J. Zaidi, S. Waheed, and S. Ahmad
The proposed reference material from the International Atomic Energy Agency, namely IAEA-407 (Fish Homogenate) was analyzed using instrumental neutron activation analysis (INAA). 15 elements, Al, As, Cl, Co, Cr, Fe, Hg, Mg, Mn, K, Na, Sb, Se, V and Zn, were determined using two irradiations (5 minutes and 5 hours) and four countings. IAEA-MA-A-1/TM (Copepoda Homogenate), NIST-SRM-1566 (Oyster Tissue), NIST-SRM-1572 (Citrus Leaves) and NIST-SRM-1577a (Bovine Liver) were utilized as standards in the quantification step.
By the use of non-destructive neutron activation analysis (NAA) twenty-four trace (Ag, As, Br, Cd, Ce, Cr, Co, Cu, Eu, Fe, Hf, I, La, Mn, Ni, Rb, Sb, Sc, Se, Sm, Sr, U, V and Zn) and six minor (Ca, Cl, Mg, K, Na and S) elements were determined in a certified marine tissue standard reference material. Four non-destructive methods including thermal, epi-thermal, prompt-gamma ray and delayed neutron counting activation analyses were performed. Results when compared to the certified values showed the reliability of employing these methods in such standards program.
Authors:Kwangwon Park, Kyunghaeng Cho, and Namgoo Kang
The comparator instrumental neutron activation analysis (INAA) method was used for certification of arsenic in Korea Research
Institute of Standards and Science (KRISS) reference materials 108-04-001 (Oyster Tissue). The certified value was determined
by analyzing one sample of approximately 0.15 g from ten bottles selected by random sampling. Potentially significant sources
of uncertainty were taken into consideration using the guideline given by ISO. A complete evaluation of all sources of uncertainty
yielded an expanded uncertainty for the mean value of this reference material of 4.7% at approximately 95% level of confidence.
Authors:C. Günther, R. Pfestorf, M. Rother, J. Seidel, R. Zimmermann, G. Wolf, and V. Schröder
The enthalpy of solution of KCl in H2O (1∶2000 mol·mol−1) at 298.15 K was measured in an interlaboratory test in the G.D.R. The test material was prepared in the ASMW laboratories. The purity found on the high-precision coulometric titration of chloride was 0.9999±0.0001 g·g−1. The consensus value of the enthalpy of solution in the test was ΔHs298.15=17.47±0.07 kJ·mol−1. This result is in good agreement with experimental values from recognized international scientific laboratories. The test material is applicable as a CRM.
Authors:J. Leggitt, K. Inn, S. Goldberg, R. Essex, S. LaMont, and S. Chase
The admissibility of nuclear forensics measurements and opinions derived from them in US Federal and State courts are based
on criteria established by the US Supreme Court in the case of Daubert v. Merrell Dow and the 2000 Amendment of Rule 702 of
the Federal Rules of Evidence. These criteria are being addressed by new efforts that include the development of certified
reference materials (CRMs) to provide the basis for analytical method development, optimization, calibration, validation,
quality control, testing, readiness, and declaration of measurement uncertainties. Quality data is crucial for all stages
of the program, from R&D, and database development, to actual casework. Weakness at any point in the program can propagate
to reduce the confidence of final conclusions. The new certified reference materials will provide the necessary means to demonstrate
a high level of metrological rigor for nuclear forensics evidence and will form a foundation for legally defensible nuclear
chemical analysis. The CRMs will allow scientists to devise validated analytical methods, which can be corroborated by independent
analytical laboratories. CRMs are required for ISO accreditation of many different analytical techniques which may be employed
in the analysis of interdicted nuclear materials.
Authors:Vikram Kestens, Guy Auclair, Katarzyna Drozdzewska, Andrea Held, Gert Roebben, and Thomas Linsinger
In this study, the use of differential scanning calorimetry (DSC) is demonstrated as a powerful technique that can provide
accurate thermodynamic property values of environmental contaminants such as polycyclic aromatic hydrocarbons (PAHs). In total,
47 high purity PAH certified reference materials were selected and analysed by DSC. Their onset melting temperature, enthalpy
of fusion and eutectic purity were calculated from the obtained melting endotherms. In addition, the entropy of fusion, which
was calculated from the onset melting temperature and enthalpy of fusion, is presented. All measurements were evaluated in
a metrologically rigorous manner, including measurement uncertainties.
Authors:M. Jamali, T. Kazi, M. Arain, H. Afridi, J. Baig, and A. Shah
., Lopez-Sanchez, J. F., Rubio, R., Rauret, G., Thomas, R. P., Davidson, C. M., Ure, A. M. (1999): Use of a certifiedreferencematerial for extractable trace metals to assess sources of uncertainty in the BCR three-stage sequential extraction procedure
Authors:Tassiane Matsubara, Mitiko Saiki, and Guilherme Zahn
In recent years, environmental concerns regarding antimony have grown considerably due to anthropogenic processes that have
resulted in increasing concentration of Sb in the environment, and also because of its impacts and possible adverse effects
to living organisms. Several techniques have been used, to obtain reliable results for Sb, since Sb is present at low level
concentration, requiring analytical instrumentation with low detection limits. The neutron activation analysis (NAA) technique
has a high metrological level for the determination of several elements in different matrices. However, Sb determination in
environmental and biological samples presents some analytical difficulties due to its low concentrations and gamma ray spectrum
interferences. The objective of this research was to study on Sb determination in environmental reference materials by NAA.
Ten environmental reference materials were selected and analyzed using long period irradiation at IEA-R1 research nuclear
reactor. The induced gamma activities of 122Sb and 124Sb were measured. Relative errors of the results demonstrated that the accuracy depends mainly on Sb radioisotope measured,
the decay time for counting and the sample composition.