Authors:N. Siddique, Sabiha-Javied, S. Waheed, and M. Tufail
Analysis of geological materials requires the use of matrix specific reference materials (RMs). Phosphate rocks (PR), the
basic ingredient of phosphate fertilizers, are very important in agriculture. A project was undertaken to study the PRs of
the Hazara Deposits of Pakistan. Due to the unavailability of phosphate rock reference materials (PR-RMs) with a large number
of certified elements, validation of the results was problematic when carrying out elemental analysis of PR samples and their
derived products. Therefore a parallel study was performed to determine the composition of three phosphate based RMs; BCR-RM-032
(Natural Moroccan Phosphorite), IAEA-434 (Phosphogypsum) and PRH (a local PR-RM from the Hazara Deposits of Pakistan). Instrumental
Neutron Activation Analysis was used for this purpose and more than 30 elements including rare earth elements were determined
in the three PR samples.
Silver in selected, predominantly biological, reference materials (NIST SRM 1515, 1547, 1549, 1566a, 1571, 1577b, 2704, CTA-OTL-1,
and Bowen’s Kale) was determined using neutron activation analysis (NAA) in two different analytical modes: instrumental NAA
with epithermal neutrons (ENAA), and NAA with radiochemical separation (RNAA). The ENAA mode was based on long-time 5-hour
irradiation of samples in a special Cd lined box with counting after 8-month decay. The RNAA procedure consisted in 20-hour
irradiation of samples, their decomposition/dissolution by alkaline-oxidative fusion, and precipitation of AgCl including
several purification steps. Both methods provided Ag contents in the analyzed reference materials consistent with certified
and/or literature values down to the ng·g−1 level.
Authors:P. Povinec, M. Pham, J. Sanchez-Cabeza, G. Barci-Funel, R. Bojanowski, T. Boshkova, W. Burnett, F. Carvalho, B. Chapeyron, I. Cunha, H. Dahlgaard, N. Galabov, L. Fifield, J. Gastaud, J. Geering, I. Gomez, N. Green, T. Hamilton, F. Ibanez, M. Ibn Majah, M. John, G. Kanisch, T. Kenna, M. Kloster, M. Korun, L. Liong Wee Kwong, J. La Rosa, S. Lee, I. Levy-Palomo, M. Malatova, Y. Maruo, P. Mitchell, I. Murciano, R. Nelson, A. Nouredine, J. Oh, B. Oregioni, G. Le Petit, H. Pettersson, A. Reineking, P. Smedley, A. Suckow, T. van der Struijs, P. Voors, K. Yoshimizu, and E. Wyse
A reference material designed for the determination of anthropogenic and natural radionuclides in sediment, IAEA-384 (Fangataufa
Lagoon sediment), is described and the results of certification are presented. The material has been certified for 8 radionuclides
(40K, 60Co, 155Eu, 230Th, 238U, 238Pu, 239+240Pu and 241Am). Information values are given for 12 radionuclides (90Sr, 137Cs, 210Pb (210Po), 226Ra, 228Ra, 232Th, 234U, 235U, 239Pu, 240Pu and 241Pu). Less reported radionuclides include 228Th, 236U, 239Np and 242Pu. The reference material may be used for quality management of radioanalytical laboratories engaged in the analysis of radionuclides
in the environment, as well as for the development and validation of analytical methods and for training purposes. The material
is available from IAEA in 100 g units.
A simple method was developed for the low level determination of manganese in biological materials by neutron activation analysis with radiochemical separation based on manganese dioxide precipitation. Precision and accuracy of the method were tested by analyses of IAEA reference materials Animal Muscle H-4, Milk Powder A-11, Freeze Dried Animal Blood A-13, Horse Kidney H-8, and Mixed Human Diet H-9. Interferences from iron and cobalt were also evaluated.
Neutron activation analysis (NAA) is used extensively at the National Bureau of Standards as one of the analytical techniques in the certification of Standard Reference Materials (SRMs). Characteristics of NAA which make it valuable in this role are: accuracy; multielemental capability; ability to assess homogeneity; high sensitivity for many elements, and essentially blank-free nature. Examples of recent SRM analyses illustrating these characteristics are described.
Authors:Zhang Yuanxun, Qian Yine, Li Deyi, Wang Yinsong, and Wang Xuepeng
The IAEA-386 bovine liver candidate reference material is prepared specially for micro-analytical techniques. The development
process including material collection, drying, pulverizing, sieving, homogenization and preliminary test is described in detail.
More effective grinding methods were established to achieve the median partiele size of 22 μm. For reasons of quality control
and better assessment of resulting data, its certification campaigns on world-wide will be organized by the IAEA.
Authors:G. Guzzi, A. Colombo, F. Girardi, R. Pietra, G. Rossi, and N. Toussaint
Three different analytical techniques: INAA, X-ray fluorescence and atomic absorption spectrometry were used at the JRC Ispra
to test the total homogeneity of four candidate botanic reference materials supplied by NBS. Without adopting complex statistical
formalities a “degree of inhomogeneity” was estimated in each sample for the elements considered in the test. The operating
procedures and the results obtained are presented and discussed.
Several organic compounds like phenanthrene, benzanilide, anisic acid, triphenylene, 2-chloroanthraquinone, hexachlorobenzene, carbazole, 4-iodobenzoic acid, perylene, anthraquinone, as new reference materials for temperature and energy calibration of DTA and DSC apparatuses were studied in the range 300—600 K.
Authors:J. Zaidi, I. Qureshi, M. Arif, and I. Fatima
IAEA and NBS biological certified reference materials have been analyzed by instrumental neutron activation analysis and concentration of 17 elements was determined. The elements determined were either completely missing or their certified values were not given in the original compilations. For quality assurance of our work, a comparison of data on missing trace elements in some of the CRMs has been presented. It seems that second round of analysis for the certification of these elements would be useful.
Instrumental neutron activation analysis in conjunction with Compton suppression methods has been used to determine chromium concentrations in 13 biological reference materials. Special attention was focussed on the interferences and the ways of lowering their contribution. Separate data was obtained for normal and Compton suppressed modes of counting so that a comparison could be performed. The results for chromium as compared to the certified or compilation values were in excellent agreement.