Characterization of trace elements in Casearia medicinal plant by neutron activation analysis

Leaves of Casearia sylvestris, Casearia decandra and Casearia obliqua plant species, collected at the Atlantic Forest in Brazil, were analyzed by using instrumental neutron activation analysis (INAA). Short and long irradiations using thermal neutron flux of the IEA-R1 nuclear reactor were carried out for these analyses. Concentrations of Ca, K and Mg were found in these samples at the percentage levels, Br, Cl, Fe, Mn, Na, Rb and Zn at the μg g⁻¹ levels and Co, Cr, Cs, La, and Sc at the μg kg⁻¹ levels. Comparisons were made among the element concentrations obtained in these three Casearia species and significant differences were found for the elements Cl, Co, Cs, Cr, La, Mn, Na and Sc. The precision and the accuracy of the results were evaluated by analyzing the certified reference materials NIST-1515 Apple Leaves and NIST-1573a Tomato Leaves.     

An evaluation of Compton suppression neutron activation analysis for determination of trace elements in some geological samples

Compton suppressed neutron activation analysis has been used for a variety of applications, but never has a detailed discussion of its use in far more complex matrices, such as geological samples, been fully addressed. This investigation seeks to serve as a qualitative evaluation of Compton suppression neutron activation analysis (CSNAA) and to illustrate the benefits of using Compton suppression with thermal and epithermal neutrons for the analysis of several geological specimens.     

Application of spectral decomposition analysis to in vivo quantification of aluminum by neutron activation analysis

The toxic effects of aluminum are cumulative and result in painful forms of renal osteodystrophy, most notably adynamic bone disease and osteomalacia, but also other forms of disease. The Trace Element Group at McMaster University has developed an accelerator-based in vivo procedure for detecting aluminum body burden by neutron activation analysis (NAA). Further refining of the method was necessary for increasing its sensitivity. In this context, the present study proposes an improved algorithm for data analysis, based on spectral decomposition. A new minimum detectable limit (MDL) of (0.7±0.1) mg Al was reached for a local dose of (20±1) mSv. The study also addresses the feasibility of a new data acquisition technique, the electronic rejection of the coincident events detected by a NaI(Tl) system. It is expected that the application of this technique, together with spectral decomposition analysis, would provide an acceptable MDL for the method to be valuable in a clinical setting.     

Calcium supplements as source of trace elements: Adequacy and safety of supplements with vitamin C,vitamin D and phosphate formulations

Instrumental neutron activation analysis and atomic absorption spectrometry were used to quantify trace elements in different national and multinational Ca supplements categorized on the basis of Ca with vitamin D, vitamin C and phosphate formulations. The supplements were found to contain low levels of Co, Cr and Cu with elevated amounts of Fe, K and Na. Toxic elements (As, Cd and Sb) were detected in very few samples at very low concentrations. The essential elements contribute to >3% of their respective Dietary Reference Intakes.     

Simultaneous determination of some trace elements in biological materials by neutron activation analysis

Neutron activation analysis (NAA) for the determination of some trace elements in biological samples is described. This method permits the simple and rapid determination of Se, Hg, Fe, Co, Zn, Ag, Sn, Cr, Yb, Sb, Au and As after a radiochemical separation from Na, Cs, Rb and, partially, Br. For this purpose, precipitation by adding sulphide and hydroxyl ions was used. An attempt was made to simplify the radiochemical procedure. The present (destructive analysis) was tested in radiotracer experiments. Further tests were made using standard biological materials. The method should find applications in neutron activation analysis, particularly of biological materials.     

Multielement analysis of human hair and kidney stones by instrumental neutron activation analysis with the k0-standardization method.

This paper focuses on the evaluation of the k₀ method of instrumental neutron activation analysis in biological materials. The method has been applied in multielement analysis of human hair standard reference materials from IAEA, No. 085, No. 086 and from NIES (National Institute for Environmental Sciences) No. 5. Hair samples from people resident in different parts of Malaysia, in addition to a sample from Japan, were analyzed. In addition, human kidney stones from members of the Malaysian population have been analyzed for minor and trace elements. More than 25 elements have been determined. The samples were irradiated in the rotary rack (Lazy Susan) at the TRIGA Mark II reactor of the Malaysian Institute for Nuclear Technology and Research (MINT). The accuracy of the method was ascertained by analysis of other reference materials, including 1573 tomato leaves and 1572 citrus leaves. In this method the deviation of the 1/E¹⁺ epithermal neutron flux distribution from the 1/E law (P/T ratio) for true coincidence effects of the γ-ray cascade and the HPGe detector efficiency were determined and corrected for.     

Rare-earth elements in Egyptian granite by instrumental neutron activation analysis.

The mobilization of rare-earth elements (REEs) in the environment requires monitoring of these elements in environmental matrices, in which they are mainly present at trace levels. The similarity in REEs chemical behavior makes the separate determination of each element by chemical methods difficult; instrumental neutron activation analysis (INAA), based on nuclear properties of the elements to be determined, is a method of choice in trace analysis of REEs and related elements. Therefore, INAA was applied as a sensitive nondestructive analytical tool for the determination of REEs to find out what information could be obtained about the REEs of some Egyptian granite collected from four locations in Aswan area in south Egypt as follows wadi El-Allaqi, El-Shelal, Gabel Ibrahim Pasha and from Sehyel Island and to estimate the accuracy, reproducibility and detection limit of NAA method in case of the given samples. The samples were properly prepared together with standards and simultaneously irradiated in a neutron flux of 7 x 10(11)n/cm(2)s in the TRIGA Mainz research reactor facilities. The following elements have been determined: La, Ce, Nd, Sm, Eu, Yb and Lu. The gamma spectra was collected by HPGe detector and the analysis was done by means of computerized multichannel analyzer. The X-ray fluorescence (XRF) was also used.     

Multielement analysis of human hair and kidney stones by instrumental neutron activation analysis with the k0-standardization method

This paper focuses on the evaluation of the k₀ method of instrumental neutron activation analysis in biological materials. The method has been applied in multielement analysis of human hair standard reference materials from IAEA, No. 085, No. 086 and from NIES (National Institute for Environmental Sciences) No. 5. Hair samples from people resident in different parts of Malaysia, in addition to a sample from Japan, were analyzed. In addition, human kidney stones from members of the Malaysian population have been analyzed for minor and trace elements. More than 25 elements have been determined. The samples were irradiated in the rotary rack (Lazy Susan) at the TRIGA Mark II reactor of the Malaysian Institute for Nuclear Technology and Research (MINT). The accuracy of the method was ascertained by analysis of other reference materials, including 1573 tomato leaves and 1572 citrus leaves. In this method the deviation of the 1/E^1+α epithermal neutron flux distribution from the 1/E law (P/T ratio) for true coincidence effects of the γ-ray cascade and the HPGe detector efficiency were determined and corrected for.     

Determination of chromium and trace elements in El-Rubshi chromite from Eastern Desert,Egypt by neutron activation analysis

Neutron activation analysis (NAA) is one of the most powerful analytical techniques for multielement determination of rocks. In the present work NAA and HPGe detector γ-spectroscopy was used to determine chromium and 15 minor and trace elements qualitatively and quantitatively from chromite rock samples collected from El-Robshi area in the Eastern Desert, Egypt. The samples were properly prepared together with their standards and simultaneously irradiated by thermal neutrons at the TRIGA Mainz research reactor. Short time irradiation (1–5 min) was used to determine Mg, Ti and Mn. Long time irradiation (6 h) was used to determine Na, Ga, As, La, Sc, Cr, Fe, Co, Zn, Zr, Ce, Ce, Yb, Lu, Hf and Ta. In El-Robshi chromite comprises 18 sites, more than 100 lenses of massive chromite, more than 2700 tons averaging 44% Cr₂O₃ and the average of ⁵¹Cr 40.2%.     

Determination of trace Al in silicon carbide by epithermal neutron activation.

An approach based on utilization of epithermal neutron activation analysis (ENAA) is proposed for determination of trace Al in silicon carbide (SiC) materials. The feasibility and restrictions of the ENAA were evaluated in terms of the associated uncertainties that resulted from counting and from propagation in calculations. Experimental measurements were carried out under the specified irradiation and measurement conditions, where the results of a set of SiC standards for accuracy testing were compared with the calculated uncertainties. It is shown that the epithermal neutron activation is a simple and reliable method practically useful for analysis of SiC containing Al in concentrations (f(Al)) higher than 10(-3) weight fraction by the use of a typical nuclear reactor; the associated uncertainties can be suppressed to less than 12%. The influences of neutron quality or the cadmium ratio in 27Al(n,gamma)28Al reaction on the applicable concentrations of Al in SiC are also predicted and discussed.     

The determination of uranium in food samples by Compton suppression epithermal neutron activation analysis

Eight foods common to the Nigerian diet were analyzed for trace amounts of uranium using epithermal neutron activation analysis. Food sample sizes of roughly one-half gram, irradiated for 10 min, with a 15 min decay time and counting time for 10 min yielded detection limits between 0.02 and 0.04 Bq/kg. Dried milk, chicken pasta, spaghetti and biscuits had less than detectable amounts of uranium, while sorghum, wheat and brown beans contained 0.73, 0.23 and 0.16 Bq/kg, respectively.     

Development of k0-INAA standardization method by neutron activation with Am-Be source

The k₀-standardization method on the ²⁴¹Am-Be isotopic neutron source has been studied and developed. In this paper, the characteristics of the neutron spectrum in an isotropic neutron field of ²⁴¹Am-Be isotopic neutron sources was experimentally determined by dual monitor method using measured cadmium ratios of ¹⁹⁷Au(n, γ)¹⁹⁸Au and ⁹⁸Mo(n, γ)⁹⁹Mo(β⁻)^99mTc reactions. Application of the k₀-standardization method for the determination of elemental concentrations such as Al, Mn and Na in cement is carried out as well. The obtained results are in agreement with other analyses.     

Determination of macro,micro nutrient and trace element concentrations in Indian medicinal and vegetable leaves using instrumental neutron activation analysis

Leafy samples often used as medicine in the Indian Ayurvedic system and vegetables were analyzed for 20 elements (As, Ba, Br, Ca, Ce, Cr, Cs, Co, Eu, Fe, K, La, Na, Rb, Sb, Sc, Sm, Sr, Th, Zn) by employing Instrumental Neutron Activation Analysis (INAA). The samples were irradiated at the 100 kW TRIGA-MAINZ nuclear reactor and the induced activities were counted by gamma ray spectrometry using an efficiency calibrated high resolution High Purity Germanium (HPGe) detector. The concentration of the elements in the medicinal and vegetable leaves and their biological effects on human beings are discussed.     

Tillandsia usneoides L, a biomonitor in the determination of Ce, La and Sm by neutron activation analysis in an industrial corridor in Central Mexico

The atmosphere of the Tula Industrial Corridor in Central Mexico is contaminated due to several industries including oil refining while station monitoring in this area are limited. Lanthanides are considered fingerprint of oil refinery activities, and La, Ce and Sm have been previously detected in this area using filters. The suitability of T. usneoides as a biomonitor assessing the La, Ce and Sm concentrations in Particulate Matter is evaluated by NAA. Results of both biomonitor and filters are highly correlated.     

Heavy metals and rare earth elements source-sink in some Egyptian cigarettes as determined by neutron activation analysis.

Heavy metals and rare earth elements in two types of cigarettes were studied. The contents of trace elements were determined by using delayed neutron activation analysis. In the present study 11 elements have been detected in popular and fine brand cigarettes marketed in Egypt. Evaluation of these elements with their potential hazards for smokers is briefly discussed. The material balance (source and sink) for each element was determined. Also the ratio of element recovery to the total amount was assessed.     

Characterization of neutron flux spectra in irradiation sites of MNSR reactor using the Westcott-formalism for the k0 neutron activation analysis method.

For the general applicability of the k0-NAA method to deal with "non-l/v" (n,gamma) reaction nuclides, the modified spectral index r(alpha) square root (Tn/T0) and g(Tn) factor for monitoring neutron temperature Tn for the inner and outer irradiation sites of the Ghana MNSR reactor (GHARR-1) were measured using the Cd-ratio method. Using the measured Cd ratio for lutetium and the modified spectral index, the reduced resonance integral of lutetium s0,Lu was also calculated. The computed result of 1.64 was in good agreement with the reported value of 1.67. Based on the assumption that the definitions of reaction rates in the Westcott-formalism and in Nisle's unified formulation are equal, a theoretical verification of the accuracy of the measured modified spectral indices for our data and those reported in the literature for other research reactors was carried out. Employing 197Au, 96Zr and 94Zr as "1/v" monitors, the theoretical values which depend on the choice of the monitor, followed the trend for measured values of the sub- to epi-cadmium flux ratio f for nine irradiation sites of four different research reactors. The computed and experimental modified spectral indices for the different flux ratios associated with irradiation sites within the range 18.8-152 fitted well to a simple exponential relationship. Calculated and measured data are in good agreement when appropriate correction factors are used.     

Forensic investigation of brick stones using instrumental neutron activation analysis (INAA), laser ablation–inductively coupled plasma–mass spectrometry (LA–ICP–MS) and X-ray fluorescence analysis (XRF)

Brick stones collected from different production facilities were studied for their elemental compositions under forensic aspects using laser ablation–inductively coupled plasma–mass spectrometry (LA–ICP–MS), instrumental neutron activation analysis (INAA) and X-ray fluorescence analysis (XRF). The aim of these examinations was to assess the potential of these methods in forensic comparison analyses of brick stones. The accuracy of the analysis methods was evaluated using NIST standard reference materials (679, 98b and 97b). In order to compare the stones to each other, multivariate data analysis was used. The evaluation of the INAA results (based on the concentrations of V, Na, K, Sm, U, Sc, Fe, Co, Rb and Cs) using principal component analysis (PCA) and cluster analysis is presented as an example. The results derived from the different analytical methods are consistent. It was shown that elemental analysis using the described methods is a valuable tool for forensic examinations of brick stones.