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.     

Elemental analysis of two Egyptian iron ores and produced industrial iron samples by neutron activation analysis.

Elemental analysis of two iron ores and initial industrial iron production prepared by the Egyptian Iron and Steel Company of Helwan near Cairo were performed by the instrumental neutron activation analysis technique. Five samples of each type were irradiated for 48 h in a thermal neutron flux of 4 x 10(12) n/cm2 s in the first Egyptian research reactor ET-RR-1. Also, the Pneumatic Irradiation Rabbit System (PIRS), attached to the reactor ET-RR-1 in Inshass, was used to measure short-life elements. The gamma-ray spectra were obtained with a hyper pure germanium detection system. The concentration percentage values of major, minor and trace elements are presented. Implications of the elemental concentration values obtained are presented.     

Elemental content of feldspar from Eastern Desert,Egypt, determined by INAA and XRF

Instrumental neutron activation analysis (INAA) and HPGe detector γ-spectroscopy were used to determine a total of 16 elements qualitatively and quantitatively for the first time from feldspar rock samples collected from Gabel El Dubb, Eastern desert, Egypt. The elements determined are (Na, Mg, K, Sc, Ga, Cr, Fe, Co, Zn, Nb, Ba, Ce, Eu, Hf, Th and U). The samples were properly prepared together with their standard reference material and simultaneously irradiated by thermal neutrons at the TRIGA Mainz research reactor at a neutron flux of 7×10¹¹ n/cm² s. XRF was also used. Comparison of the results obtained by both techniques showed good agreement for such elements as K, Na, Fe, Mg, Ba and Cr.     

Elemental investigation of some Egyptian vehicle motor alloys using neutron activation analysis.

Six samples of different Egyptian motor vehicle alloys have been investigated by neutron activation analysis to estimate the concentrations of their elemental constituents, which affect their quality. A single high resolution hyper-pure germanium HPGe gamma-ray detector and a multichannel analyzer are used to collect the gamma-ray spectra. A HPGe-HPGe coincidence spectrometer was also used to confirm the identity of certain peaks. Thirteen trace elements (Sc, Cr, Fe, Co, Zn, Sn, Sb, La, Sm, Eu, Hf, Pt and Au) were observed in the spectra and their concentrations were determined. A comparative study on the element concentrations for the six samples is given.     

Validation of a neutron activation analysis method using k0-standardization.

A neutron activation analysis method using k0-standardization has been adopted for multielement analysis using our research reactors. Gold has been used as the comparator. The input parameters, used for calculation of elemental concentration, such as subcadmium to epithermal neutron flux ratio (f), the epithermal neutron flux shape factor (alpha), and the absolute efficiency of the detector (epsilon) have been determined. The values of k0-factors and Q0 (the ratio of resonance integral to thermal neutron cross section) have been taken from the literature. The validity of applying this method in our laboratory is evaluated by analyzing the elemental concentrations with respect to the certified values in eight reference materials of different origin obtained from USGS, IAEA and NIST. The percent deviation of the measured elemental concentrations are found to be within +/- 15% to that of the certified values whereas the percent relative standard deviation ranged from 2% to 10% for most of the elements analyzed.     

Heavy metals and rare earth elements in phosphate fertilizer components using instrumental neutron activation analysis.

The technique of instrumental neutron activation analysis was applied as a sensitive nondestructive analytical tool for the determination of heavy metals and rare earth elements in phosphate fertilizer ingredients. The contents of heavy metals Fe, Zn, Co, Cr and Sc as well as rare earth elements La, Ce, Hf, Eu, Yb and Sm were determined in four samples representing the phosphate fertilizer components (e.g. rock phosphate, limestone and sulfur). These samples were collected from the Abu-Zabal phosphate factory in El-Qalubia governarate, Egypt. The aim of this study was to determine the elemental pattern in phosphate ingredients as well as in the produced phosphate fertilizer. Fair agreement was found between the results obtained for the standard reference material Soil-7 and the certified values reported by the International Atomic Energy Agency. The results for the input raw materials (rock phosphate, limestone and sulfur) and the output product as final fertilizer are presented and discussed.     

Characterization of ophiolites from northern Havana-Matanzas petroleum fields using instrumental neutron activation analysis.

Concentrations of 16 elements from 14 serpentinitic samples from Basilio and Cantel petroleum fields were obtained by instrumental neutron activation analysis (INAA): Cr, Co, Ni, La, Nd, Sm, Eu, Gd, Tb, Ce Yb, Lu, Rb, Cs, Hf and Th. Relative INAA was performed using certified reference materials and laboratory standards. Average elemental concentrations showed that the ophiolites have a basic character, suggesting the use of a well-logging method designed for volcano-sedimentary petroleum fields.     

The influence of an additional filter in epithermal neutron activation analysis

Additional filters of tungsten and sodium in different thicknesses have been used in the epithermal neutron activation analysis of geological samples to reduce the interferences caused by resonance neutron capture in these two elements. The results show that a selective reduction of the interfering activities in favor of the activities sought can be obtained. Improvements in terms of detection sensitivity and precision in the γ-spectrometric determinations of Sc, Fe, Co, La, Sm, Eu, Gd, Tb, Yb, Lu, Th and W have been calculated.The possible applications of the filtered epithermal neutron activation analysis (FENA) method to different kinds of samples are also briefly discussed.     

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.     

Salvinia auriculata: aquatic bioindicator studied by instrumental neutron activation analysis (INAA).

Through instrumental neutron activation analysis (INAA) the elemental chemical composition of Salvinia auriculata and Ouro Preto city public water was determined. Elements Ce, Th, Cr, Hf, Sb, Sc, Rb, Fe, Zn, Co, Au, La and Br were quantified. High chromium concentration was determined in this plant. But, chromium was determined only in low concentrations in the water. The results indicate the great capacity of this plant to absorb and accumulate inorganic elements.     

X-ray fluorescence analysis of geological samples: exploring the effect of sample thickness on the accuracy of results.

The accuracy of the simple quantitative method of elemental XRF analysis applied to thick and thin geological samples was investigated with certified reference materials. In the case of thick samples, the intensity of the calcium signal was used as a characteristic of the sample for the dark matrix correction, as it had been found to be inversely correlated with the intensity of the silicon signal. The results of the analysis of thick samples did not depend on the sample form (pressed disc or a powder in a cup), and the absorption factors were very high. In the analysis of thin samples, the detection limits, sensitivity, and accuracy have been improved, particularly for light elements. As the absorption factors are close to unity for thin samples, there is no need for a matrix-effect correction or certified reference materials.     

Standardization of NIRR-1 irradiation and counting facilities for instrumental neutron activation analysis.

The first nuclear reactor in Nigeria, the Nigeria Research Reactor-1 (NIRR-1), is a Miniature Neutron Source Reactor (MNSR). It was specifically acquired for elemental analysis by the neutron activation analysis (NAA) technique. In this work, routine experimental schemes for the determination of over 30 elements of interest in different sample matrices have been developed. In order to validate the experimental procedures the following standard reference materials, IAEA-359 (Cabbage), IAEA-336 (Lichen), GSR-5 and GSD-11 (Chinese Geochemical Rock Standards), as well as IAEA-SL-3 and IAEA-405 (Sediments) were analyzed. Validated results are presented for the following elements Al, As, Au, Ba, Br, Ca, Ce, Cl, Co, Cr, Cs, Cu, Dy, Eu, Fe, Ga, Hf, In, K, La, Lu, Mg, Mn, Na, Rb, Sb, Sc, Sm, Ta, Tb, Th, Ti, U, V, Yb and Zn. To further assess analytical capabilities of the facilities, the detection limits are presented.     

Rare earth elements content in geological samples from eastern desert,Egypt, determined by instrumental neutron activation analysis

Twenty representative geological samples (tonalite, granodiorite, adamellite, syenogranite, rapakivi syenogranite, alkali feldspar granite and monzogranite) were collected from G. Kattar area in Eastern Desert, Egypt, for analysis by instrumental neutron activation as a sensitive nondestructive analytical tool for the determination of 14 rare earth elements (REEs) and to find out the following: (1) what information could be obtained about the REEs and distribution patterns of REEs in geological samples under investigation, (2) to estimate the accuracy, reproducibility and detection limit of the INAA method in case of the given samples. The samples were properly prepared together with standard reference material and simultaneously irradiated in a neutron flux of 7×10¹¹ n/cm² s in the TRIGA Mainz research reactor facilities. The gamma spectra were collected by an HPGe detector and the analysis was done by means of a computerized multichannel analyzer. The choice of the nuclear reaction, irradiation and decay times, and of the proper gamma radiation in counting are presented and discussed. The results are found to be in good agreement with certified values.     

Comparison between different types of glass and aluminum as containers for irradiation samples by neutron activation analysis.

Three different types of glass and four different kinds of aluminum sheet have been analyzed using neutron activation analysis. The irradiation facilities of the first Egyptian research reactor (ET-RR-1) and a hyper-pure germanium (HPGe) detection system were used for the analysis. Among the 34 identified elements, the isotopes 60Co, 65Zn, 110mAg, 123mTe, 134Cs, 152Eu and 182Ta are of special significance because of their long half-lives, providing a background interference for analyzed samples. A comparison between the different types of containers was made to select the preferred one for sample irradiation.     

Optimal conditions for identifying 80Br and 128I in health food Angelica keiskei using rapid epithermal neutron activation analysis.

This study presents an optimal rapid epithermal neutron activation analysis (ENAA) technique, using a 1mm Cd filter in reactor neutron flux, to analyze 80Br and 128I in the roots, stems, and leaves of health food Angelica keiskei (AK). Various sample weights of lichen (IAEA-336) for each portion of AK, under various periods of irradiation and counting, were used to optimize the elemental analysis. Selecting the analytical conditions depends on the minimum detectable concentration (MDC), required sensitivities and the quantitative accuracy of Br and I elements. These findings imply that the MDCs of Br and I, measured under 10min activation and 5min counting followed by 10min decaying, using 350mg of lichen are ideal for elemental analysis. Moreover, each portions of AK were analyzed under optimal conditions. The elemental concentrations of Br, Cl, I, Mg, Mn and Na and their implications are discussed.     

Instrumental nuclear activation analysis (INAA) characterization of environmental air filter samples

Nuclear techniques have been used in quantitations of environmental pollutants, and instrumental neutron activation analysis (INAA) has turned out to be particularly useful in the analysis of airborne suspended particles. This work describes the INAA characterization of the particulate material in the environmental samples obtained in a monitoring campaign in Mexico City's Metropolitan Area. As the types of the irradiation facilities and gamma-ray detection system impose some limitations on the possibilities of INAA analysis, the actual experimental conditions at Gamma Spectroscopy Laboratory, where the analysis was performed, had been assessed. The facilities had been found suitable for the analysis of samples from this campaign, in which 22 elements were determined.     

Multi-element analysis of pyrite ores using polarized energy-dispersive X-ray fluorescence spectrometry.

X-ray fluorescence (XRF) spectrometry is used worldwide in geological material analysis. This study, applies polarized energy-dispersive X-ray fluorescence (PEDXRF) Spectrometer and compares in the samples of Rize-Cayeli and Mardin pyrite ores. The samples of pyrite ore were collected from the Rize and Mardin in Turkey. The prepared samples were analyzed using a PEDXRF spectrometer. The result of the analysis shows the presence of many elements including rare-earth elements (from Na to Th). The accuracy and precision of the technique for chemical analysis is demonstrated by analyzing USGS standards, GEOL, GBW 7109 and GBW-7309 sediment.     

Epithermal neutron activation,radiometric, correlation and principal component analysis applied to the distribution of major and trace elements in some igneous and metamorphic rocks from Romania

Six major (Na, Al, K, Ca, Ti, Fe) and 28 trace (Sc, Cr, V, Mn, Co, Zn, Cu, As, Br, Sr, Rb, Zr, Mo, Sn, Sb, Ba, Cs, La, Ce, Nd, Eu, Sm, Tb, Hf, Ta, W, Th and U) elements were determined by epithermal neutron activation analysis (ENAA) in nine Meridional Carpathian and Macin Mountains samples of igneous and metamorphic rocks. Correlation and principal factor analysis were used to interpret data while natural radionuclides radiometry shows a good correlation with ENAA results.     

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.     

Biological tissues analysis by XRF microtomography

The main of this work is to determine the elemental distribution in breast and prostate tissue samples in order to verify the concentration of some elements correlated with characteristics and pathology of each tissue observed by the X-ray transmission microtomography (μCT). The experiments were performed at the X-ray fluorescence beamline of the Brazilian Synchrotron Light Laboratory. The μCT images were reconstructed using a filtered-back-projection algorithm and the XRF microtomographies were reconstructed using a filtered-back-projection algorithm with absorption corrections.