The k0-method has been developed for 10 MW Pakistan Research Reactor (PARR-1). It involved the full energy peak efficiency calibration of HPGe detector for different counting geometries and characterization of neutron flux at three irradiation channels. Neutron flux was characterized for thermal to epithermal flux ratio, epithermal flux shape factor, modified spectral index, Westcott´s g-factor and fast flux. The method was validated by analyzing IAEA-SL1 (lake sediment) and NIST-SRM-1572 (citrus leaves). All calculations were performed in Excel. The results revealed most of the elements with good accuracy.
Samples of certified aluminum base alloys were analyzed by semi-absolute, standardless k0-instrumental neutron activation analysis (k0-INAA) for compositional decoding. Irradiations were performed at two research reactors located at Pakistan Institute of Nuclear Science and Technology having nominal thermal neutron fluxes of 1013 and 1012 cm−2 s−1. The experimentally optimized parameters for NAA suggest a maximum of three sets of irradiations for the quantification of 8 major and minor elements. Moreover, the same conditions provided quantitative results for 10 other elements as impurities, which were not reported by the supplier of the reference material. The same alloys were analyzed by inductively coupled plasma optical emission spectrometry (ICP-OES) where all impurity elements, quantified by k0-INAA, were below the detection limits. A comparison of % relative deviation of the results obtained by k0-INAA and ICP-OES revealed that the former has better accuracy than ICP-OES, but k0-INAA has poor limits of detection for Mg, Si and Ti in aluminum base alloy.
This study shows the application of semi-absolute k0 instrumental neutron activation analysis (k0-INAA), epithermal neutron activation analysis (ENAA) and atomic absorption spectrophotometry (AAS) for the determination of 21 elements (Br, Ca, Cl, Co, Cr, Cs, Cu, Fe, Hf, I, K, Mg, Mn, Na, Ni, P, Pb, Rb, Sc Sr, and Zn) in different types of milk samples. The ENAA was required for the determination of iodine, AAS for Cu, Ni and Pb and the rest of the elements were measured by k0-INAA. Thirteen elements (Br, Ca, Cl, Cs, Cu, Fe, K, Mg, Na, P, Rb, Sr and Zn) were identified in all milk samples. Ni was detected in eleven and Pb in two samples. Concentrations of most of the elements were within the ranges of the world reported data. The data was further explored by principal component analysis to find relationships between samples and elements.
Various trace elements in different types of iron based geological reference materials [JSS 804-1 (hematite), JSS 820-2 (limonite), SU-1 and SU-1a (iron-nickel-copper-cobalt ores)] were investigated using k0-instrumental neutron activation analysis (k0-INAA). To avoid the interference of iron as the matrix element, a liquid–liquid extraction procedure with diisopropyl ether (DIPE) in hydrochloric acid solution and determination of trace elements in the inorganic phase was undertaken prior to irradiation. The k0-INAA method, applied to determine the content of the investigated elements, enabled the distribution of 39 elements to be followed through their corresponding intermediate/medium and long half-lived radionuclides. The possibility of determining the content of numerous trace elements after Fe separation is an important advantage of the proposed method. k0-INAA used to determine element s in the powdered materials and in liquid form after iron extraction enabled us to follow the losses and potential contamination of some elements in the liquid–liquid extraction process. Additionally, elimination of the matrix element lowered the detection limit for some trace elements compared to their corresponding values obtained by k0-INAA.
The major and trace element contents in three iron-based ore reference materials were investigated using two methods of k0-based neutron activation analysis (k0-NAA): instrumental (k0-INAA) and radiochemical (k0-RNAA). To avoid interferences from iron in the determination of elements present at trace levels, a method using radiochemical separation was applied (k0-RNAA). Determination of the investigated elements by k0-RNAA in the aqueous phase from hydrochloric acid solution was performed after extraction of iron by diisopropyl ether (DIPE). It was found that Fe elimination lowered the limit of detection for some elements, thus enabling the determination of their content. The distribution of 39 elements (with intermediate/medium and long half-life radionuclides) present in the studied materials after Fe removal was investigated.
Nickel based alloys play important role in nuclear, mechanical and chemical industry. Two semi-absolute standardless methods,
k0-instrumental neutron activation analysis (k0-INAA) and fundamental parameter X-ray fluorescence spectrometry (FP-XRF) were
used for the characterization of certified nickel based alloys. The optimized experimental conditions for NAA provided results for 18
and XRF for 15 elements. Both techniques were unable to quantify some important alloy making elements. However, both reported results
of other elements as information values. The techniques were analyzed for their sensitivity and accuracy. Sensitivity was evaluated by
the number of elements determined by each technique. Accuracy was ascertained by using the linear regression analysis and the average
root mean squared error.
activation analysis (CPAA), neutron activation analysis (NAA) etc. The significance of quality control and assurance to internal and external verification and validation is an advanced step in the analytical life cycle. In this context, all steps in a procedure should be achieved and must be checked. The NAA technique [instrumental neutron activation analysis (INAA) and k 0 -standardization neutron activation analysis (k0 -INAA)] has been extensively used in many areas of life, such as: nutrition, biology, and environment fields, due to its high sensitivity, precision
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