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Journal of Radioanalytical and Nuclear Chemistry
Authors: J. Sterba, M. Blaauw, G. Steinhauser, M. Bichler, F. Grass, and G. Westphal

Abstract  

Combining the powers of a fast pneumatic transport system and the Automatic Activation Analyzer (AAA) of the Atominstitut in Vienna with the newest version of the IAEA k 0-Software, the application of the k 0-method to the determination of short-lived radionuclides becomes easily possible. By calculating Asp-values with the IAEA software, the often expensive and time-consuming measurement of Asp-values using certified reference materials is reduced to quality control checks. Measurements clearly show that the two approaches are equivalent, especially since both take self-absorption and neutron self-shielding into account. In this way it is possible to expand the library of the AAA with many hitherto unobtainable Asp-values. At the same time, using highly accurate Asp-values already measured for many short-lived radionuclides, k 0-values for those can be produced with a simple procedure.

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Abstract  

A new Compton suppression system (CSS) for the gamma-ray spectrometer portion of the neutron activation analysis (NAA) was set up at the RPI/ITN. The pneumatic transfer system, SIPRA, for short-lived nuclides and cyclic irradiations was improved. A full calibration procedure of the CSS and SIPRA systems was performed. Two certified reference materials, NIST-SRM-1572 (Citrus Leaves) and NIST-SRM-1633a (Coal Fly Ash) were analyzed using the calibration factors. The CSS was instrumental in lowering the detection limits of Cr, Fe, Hg, Rb, Sr, Th and Zn by reducing background and/or spectral interference considerably. The analytical results were evaluated by comparison to the NIST certified values with deviations ranging from 2% to 8% for the above mentioned elements, except Zn ranging from 10% to 15% for biological and environmental samples, respectively.

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Abstract  

Recently developed radiochemical separation scheme for the simultaneous detemination of trace amounts of molybdenum and uranium in biological materials by NAA has been further refined and used for the detemination of these elements in several certified reference materials. The method assures very selective and quantitative separation of the indicator radionuclides:99Mo-99mTc and239Np from practically all accompanying activities followed by almost interference-free measurement by gamma ray spectrometry. The method can be applied to materials of both animal and plant origin and enables correcting the molybdenum results for uranium fission interference reaction thus assuring good accuracy for both elements down to ppb levels. The detection limits amount to 2.5 ppb (Mo) and 0.15 ppb (U) for ca. 200 mg samples.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: C. Chéry, S. Herremans, V. Van Lierde, F. Vanhaecke, M. Freitas, and R. Jasekera

Abstract  

Spices were analyzed by ICP-MS for determination of the ultra-micro trace elements in the human adult, Bi, Cd, Co, Ni, Pd, Pt, Se, Sn, Te, Tl, to complement previous results obtained by INAA and by EDXRF. The spices, originating from Sri Lanka, were curry, chilli powder and turmeric powders, coriander, cinnamon, black pepper, fennel, rampeh and curry leaves, and cumin. The analytical procedure was validated by analyzing the certified reference materials NIST SRM 1572 Citrus Leaves and NIST SRM 1573 Tomato Leaves. The results indicate that spices may contribute well to the daily optimal uptake of nutrients of a human adult. The adequacy of spices as a reference material with certified ultra micro trace elements is suggested.

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Abstract  

C, N, O, F and P can be analyzed by instrumental photon activation analysis (IPAA) including decay curve analysis. The interference of 30P (T 1/2 = 149.9 s) by 15O (T 1/2 = 122.2 s) can be ruled out by direct positron measurement making use of the largely different maximum β+-energies of both nuclides (3.24 MeV and 1.73 MeV, respectively). Interference by carbon (11C) can be avoided by sub-threshold activation with 17 MeV bremsstrahlung. The short half-life of 30P allows a high productivity of the method. Reliability was demonstrated in the range of 0.2%–2% P (detection limit = 40 μg/g). Analysis of a certified reference material (BCR-CRM 063) yielded excellent agreement with the certified data.

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Abstract  

Since 1995 the k 0 instrumental neutron activation analysis has been applied at Radiochemical Laboratory, CDTN/CNEN, Brazil, by means of TRIGA MARK I IPR-R1 research reactor. At that time , f, and T n were determined and the most recent determination of these parameters confirmed the great stability of the reactor along these years. In order to verify the efficiency and accuracy of the method, several certified reference materials have been systematically analyzed. Participating in Intercomparison Exercises organized by IAEA has been an important, essential and useful procedure to quality control. CDTN is the only Brazilian Institute to apply the k 0-INAA to determine elements by means of their isotopes through short, medium and long half life using its own nuclear reactor.

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Abstract  

The k0-standardization method of INAA (instrumental neutron activation analysis) was applied to three reference materials: NIST (National Institute for Standards and Technology, Washington, D.C., USA) SRM (Standard Reference Material) 1646 Estuarine Sediment, NIST SRM 2704 Buffalo River Sediment and IAEA (International Atomic Energy Agency) CRM (Certified Reference Material) SL-1 Lake Sediment. Among the 50 elements sought yielding long-lived radioisotopes after (n, ) activation, for 32 elements numerical values were obtained, and for the remaining 18, only detection limits were estimated. When comparing the results obtained in this work to certified, recommended or other literature values, good agreement was found, proving that the same analytical procedure can be applied with confidence for analysis of environmental sediment samples.

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Abstract  

A series of measurements were carried out to establish the reliability associated with isotope ratio (235/238) measurements on uranium samples using a quadrupole inductively coupled plasma mass spectrometer (ICPMS). Figures of merit related to the isotopic measurements were determined using non certified as well as certified materials provided by the New Brunswick Laboratory (NBL). The experimental results showed that repeatability is around 0.5% while reproducibility was calculated as 0.27%. Mass discrimination was determined as 0.03% per mass unit and the system linearity check over five orders of isotope ratios yielded a mass discrimination factor (K factor) of 1.0002±0.0081 (0.81%, 2s). The mean error of measurement obtained from six different certified reference materials was 0.77%.

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Abstract  

In the boron neutron capture therapy, an accurate determination of the boron content in a biological sample is very important. The boron content was investigated with a standard solution of boron which was administered intraperitoneally with a dose of 750 mg/kg body weight into mice induced cancer cells and tumors. The boron content for two types of a sample was compared to the boronophenylalanine for the tumor and the ethylamine derivatives for the induced cancer cell, which were also investigated for their accumulation rate in each organ such as blood, spleen, liver, kidney and brain. An analytical quality control was carried out by using certified reference materials such as Peach Leaves, Apple Leaves and Spinach Leaves. The relative error of the measured values was in good agreement within 2% to the certified values.

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Summary  

Instrumental neutron activation analysis was applied to evaluate the chemical composition of metallic materials, namely iron, steel, silicon and ferrosilicon certified reference materials. As, Co, Cr, Mn, Mo, Ni, V and W concentrations were analyzed in the iron and steel samples whereas 21 elements were determined in silicon and ferrosilicon samples. Accuracy and precision results of about 10% were achieved for most elements, indicating that the technique is suitable for the analysis of metallic materials. Interferences of Cr and Mn in V; Fe and Co in Mn; Co in Fe and Cr in Ti were quantified and only the last one was critical to the analysis of the materials employed in this work.

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