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Role of activation analysis in the preparation of reference materials
Kučera, Jan
The fundamentals of neutron activation analysis (NAA) and prompt gamma activation analysis (PGAA) and practices of both methods are briefly review, together with enlightening their specific role in the preparation of reference materials. The importance of homogeneity testing for the certification and use of reference materials (RMs) using NAA is appraised. Examples of the use of NAA and PGAA for the certification of element contents in environmental, biological, and material science RMs produced by world-leading institutions, such as U.S. NIST, IRMM, IAEA and by national institutions, as well, at the Nuclear Physics Institute within last almost 30 years are presented.
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A comparative study of the total mercury determination in highly contaminated soils by AAS and RNAA methods
Sysalová, J. ; Kučera, Jan ; Zvěřina, O.
High total mercury (T-Hg) contents in soils, up to 25 mg kg−1, were determined by two independent methods: a one-purpose atomic absorption spectrometer AMA-254 (Advanced Mercury Analyser) with direct solid sampling, and radiochemical neutron activation analysis (RNAA), using sample masses of 10 mg to 25 mg and about 150 mg, respectively. An excellent agreement between results of both methods was obtained. For quality control (QC) purposes, NIST SRM 2711 Montana Soil and NIST SRM 2711a were analysed by both methods using the above sample masses. The results obtained were compared with the NIST certified values within the uncertainty margins, thus proving the accuracy of the procedures employed. It has been found that the cryogenic grinding used provided sufficiently representative and homogeneous samples. A test in which HgS was analysed by RNAA showed that even mercury present in sulfide form would be fully recovered using the procedures employed. For contents of T-Hg above the upper limit of the AMA-254 working range (500 ng), samples were firstly diluted with sea sand in the ratio 1:10 and homogenised well to get RSD below 5%. The dilution procedure was verified using the certified reference material ERM-CC580 Estuarine Sediment.
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Determination of Sr, Ba, Rb, and Cs in biological reference materials using a radiochemical group separation procedure
Mizera, Jiří ; Řanda, Zdeněk
Strontium, barium, rubidium, and cesium in selected, predominantly biological, reference materials was determined using neutron activation analysis (NAA) in two different analytical modes - instrumental NAA with epithermal neutrons, and NAA with radiochemical group separation of Sr-Ba and Rb-Cs (RNAA). The RNAA procedure was based on decomposition of irradiated samples by alkaline-oxidative fusion followed by precipitation of Sr and Ba sulfates, and sorption of Rb and Cs onto ammonium phosphomolybdate.
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