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Abstract  

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.

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Abstract  

The present paper describes radiochemical separation procedures developed for the determination of the elements As, Cr, Hg, Sb and Se in biological reference materials. The methods chosen utilize ion exchange, retention on inorganic exchangers and solvent extraction techniques for the isolation of the elements of interest. These procedures are more rapid than previously used methods, such as distillation and precipitation. As to the sample dissolution, the following procedures were tested using radioactive tracers and reference materials: treatment of the materials in teflon bombs with a mixture of HNO3+H2SO4 or HNO3 only in a normal oven, and with HNO3 in a microwave oven using specially designed digestion bombs.

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Journal of Radioanalytical and Nuclear Chemistry
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

Abstract  

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.

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Abstract  

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.

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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.

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Abstract  

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.

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Abstract  

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.

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Abstract  

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.

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Abstract  

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.

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Abstract  

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.

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