Characterization of Japanese color sticks by energy dispersive X-ray fluorescence,X-ray diffraction and Fourier transform infrared analysis

This work comprises the use of energy dispersive X-ray fluorescence (EDXRF), X-ray diffraction (XRD) and Fourier transformed infrared (FTIR) techniques for the study of the composition of twentieth century traditional Japanese color sticks. By using the combination of analytical techniques it was possible to obtain information on inorganic and organic pigments, binders and fillers present in the sticks. The colorant materials identified in the sticks were zinc and titanium white, chrome yellow, yellow and red ochre, vermillion, alizarin, indigo, Prussian and synthetic ultramarine blue. The results also showed that calcite and barite were used as inorganic mineral fillers while Arabic gum was the medium used. EDXRF offered great potential for such investigations since it allowed the identification of the elements present in the sample preserving its integrity. However, this information alone was not enough to clearly identify some of the materials in study and therefore it was necessary to use XRD and FTIR techniques.     

Determination of uranium in process stream solutions from uranium extraction plant employing energy dispersive X-ray fluorescence spectrometry

Energy dispersive X-Ray fluorescence (EDXRFS) method is developed and standardized for the determination of uranium on routine basis in various process stream solutions, covering a vide range of concentrations from 0.1 to 400?g?L^?1, from an Uranium Extraction Plant at Nuclear Fuel Complex. The method has been applied to aqueous stream samples. Except for dilution, no much sample preparation was involved in the analysis and accordingly the experimental parameters were optimized. The calibration curve in the range of 0.1?C10?g?L^?1 of U was drawn manually using synthetic standard solutions prepared from U₃O₈ powder and L?? (13.61?keV) line of uranium was used for the measurements. The results from EDXRFS method are compared with other methods and are found to be in good agreement. The EDXRFS measurements carried over a range of 0.1?C350?g?L^?1 of uranium have shown a RSD of ±1?C5%. Also, the limitations of reported methods in literature and the advantages of present method are highlighted in the paper.     

Application of energy dispersive X-ray fluorescence spectrometry as multielemental analysis to determine the elemental composition of crumb rubber samples

The elemental content of different rubber samples was analyzed using different analytical methods (inductively coupled atomic emission spectroscopy and non-polarized energy dispersive X-ray fluorescent spectroscopy). A new application of energy dispersive X-ray spectrometry as an analytical method for the determination of elemental content of rubber samples was investigated. Control analyses were also carried out to compare the results by ICP-AES. In one hand four samples contained same quality of elements (Mg, Si, P, S, Ca, Fe, Zn), while another four samples were without phosphorous. On the other hand there were significant differences in the ratio of C/H in the case of each sample. Based on the results, it was concluded that the X-ray spectrometry as an analytical method is well-applicable to determine the elemental composition of rubber samples, but the calibration is a key part of the analysis. A good correlation was observed between the different methods, but the correlation was the function of characteristic of matrices. Significant matrix effect from the presence of phosphor was observed in the case of some samples, while the change of C/H ratio could not result notable matrix effect.     

Non-invasive identification of chemical compounds by energy dispersive X-ray fluorescence spectrometry, combined with chemometric methods of data evaluation

Chemicals from customers’ returns have to be analyzed before they can be reused as raw materials in production. A procedure for non-invasive qualitative analysis of compounds in a closed container based on energy dispersive X-ray fluorescence (EDXRF) spectrometry is described. EDXRF was chosen as method for non-invasive analysis of chemicals through PE bottle walls without opening the bottle. This analysis aims for a quick proof of correspondence between the declaration of a reagent on the label of the bottle and its content. This analytical result cannot be achieved by a mere evaluation of characteristic element lines in EDXRF-spectra in combination with the method of matrix correction or the method of mean atomic number. These methods take into account only a small part of the total information available in an X-ray spectrum. It is shown here that valuable additional information is extractable from the spectral ranges of the Compton-scattering and Rayleigh-scattering areas by the use of methods of multivariate data analysis, especially by principle component analysis (PCA). Regularized discriminant analysis (RDA) was employed to establish a classification scheme for unknown samples.     

Application of energy dispersive X-ray fluorescence spectrometry for the determination of some inorganic pollutants in gravitation dust sediments

Energy dispersive X-ray fluorescence spectrometry with radionuclide excitation has been applied to determine As, Cu, Fe, Pb, Rb, Sr, Ti, Zn and Zr in inorganic pollutants of gravitation dust sediments. Application of this technique required a complete optimization including sampling and their preparation for analysis and evaluation. This method has been finally used to analyze series of samples of dust sediments.     

Assessment of the Lake Gendabi salt for trace elements and toxic heavy metals by energy dispersive X-ray fluorescence spectrometry

This study has analyzed samples of salts from Lake Gendabi, located in the northern part of Tanzania for metal contamination using the EDXRF spectrometry. The aim of the study was to assess the suitability of the salt from Lake Gendabi for human consumption. Seventy-five samples of salt were collected from the Lake Gendabi floor and grouped into five grades (G1, G2, G3, G4 and G5) depending on the position of the salt from the lake shore. In addition to Na and Cl, concentrations of 17 more elements were determined in all five grades of salt. These included seven toxic metals which are Al, Ni, Cr, Cd, Pb as well as Th and U which are both toxic and radioactive. The concentrations of all toxic elements found in the samples were higher than their Maximum tolerable limits set by international organizations. As this salt is used in many parts of Tanzania, it is proposed that the salt should be thoroughly purified before entering the market. Further research to include salt samples from other salt production areas in Tanzania is recommended.     

Total reflection X-ray fluorescence analysis of river waters in its stream across the city of Cordoba,in Argentina

The aim of this work was to analyze the composition of river waters and to study their quality by detecting possible contaminants. The samples were taken at 32 points of the Suquía River in its stream across the city of Córdoba (in the Province of Córdoba, Argentina). The samples were analyzed with total reflection X-ray fluorescence (TXRF) using beam guides. Beam guides made of two Si plate reflectors were used as sample carriers and to guide the X-ray photons to the sample; the measurements were taken using the characteristic configuration that ensures the best excitation and detection conditions (in TXRF). The analyses were carried out by preconcentration of the water samples and by adding an internal standard (Gallium); small amounts of samples (30 μl) were deposited on the Si reflector plate and they were then analyzed in the total reflection regime. Spectra were analyzed with standard methods using conventional programs. The results show interesting behaviors of the concentration of trace elements along the river: elements of low atomic number (such as Ca, Cl, S, K) present higher concentrations as compared to high Z elements (such as Fe, Zn, Br, Sr); the concentrations of light elements follow a similar behavior along the stream, the same situation is observed in the set of elements with high atomic number. Some samples present high concentrations in certain elements indicating possible sources of contamination.     

Performance of a gaseous detector based energy dispersive X-ray fluorescence imaging system: Analysis of human teeth treated with dental amalgam

Energy dispersive X-ray fluorescence (EDXRF) imaging systems are of great interest in many applications of different areas, once they allow us to get images of the spatial elemental distribution in the samples. The detector system used in this study is based on a micro patterned gas detector, named Micro-Hole and Strip Plate. The full field of view system, with an active area of 28 × 28 mm² presents some important features for EDXRF imaging applications, such as a position resolution below 125 μm, an intrinsic energy resolution of about 14% full width at half maximum for 5.9 keV X-rays, and a counting rate capability of 0.5 MHz. In this work, analysis of human teeth treated by dental amalgam was performed by using the EDXRF imaging system mentioned above. The goal of the analysis is to evaluate the system capabilities in the biomedical field by measuring the drift of the major constituents of a dental amalgam, Zn and Hg, throughout the tooth structures. The elemental distribution pattern of these elements obtained during the analysis suggests diffusion of these elements from the amalgam to teeth tissues.     

A case study on uptake of thorium from soil to plant by using X-ray fluorescence spectrometry

A case study was carried out to determine the uptake of thorium from soil to plant by using X-ray fluorescence technique. The radioecological experiment was undertaken to provide plant/soil concentration ratio (CR) data for thorium using 2 types of plant (barley and common vetch)×4 levels of Th(0, 1500, 3000,4500ppm)×2 types of soil (acidic and alkaline) with different configuration parameters. The calibration of the analytical method for thorium on dry basis of samples is described by using¹⁰⁹Cd excitation source. The results indicated that theCR values decreased with the corresponding Th concentration in soils with a 1000 fold range and differed among soil and plant types.     

Study of the distribution of actinides in human tissues using synchrotron radiation micro X-ray fluorescence spectrometry

This study aims at evaluating the capabilities of synchrotron radiation micro X-ray fluorescence spectrometry (SR micro-XRF) for qualitative and semi-quantitative elemental mapping of the distribution of actinides in human tissues originating from individuals with documented occupational exposure. The investigated lymph node tissues were provided by the United States Transuranium and Uranium Registries (USTUR) and were analyzed following appropriate sample pre-treatment. Semi-quantitative results were obtained via calibration by external standards and demonstrated that the uranium concentration level in the detected actinide hot spots reaches more than 100 μg/g. For the plutonium hot spots, concentration levels up to 31 μg/g were found. As illustrated by this case study on these unique samples, SR micro-XRF has a high potential for this type of elemental bio-imaging owing to its high sensitivity, high spatial resolution, and non-destructive character.

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Graphical Abstract SR micro-XRF study of the distribution of actinitides in human tissues. Left Location of the U-contaminated tissue sample in the human body. Middle U distribution derived from the high resolution SR micro-XRF scan on the tissue sample, indication of five U hot spots. Right Detail of the point measurement spectrum of U hot spot 3, intense U-L_α fluorescence peak located at 13.6 keV.

     

Simultaneous determination of parts-per-million level Cr,As, Cd and Pb,and major elements in low level contaminated soils using borate fusion and energy dispersive X-ray fluorescence spectrometry with polarized excitation

Energy-dispersive polarized X-ray fluorescence (ED-P-XRF) spectrometry was evaluated for the analysis of low level contaminated soils for four important contaminant elements (Cr, As, Cd and Pb) and major elements (Fe, Mn, Ti, P, Ca, K, Si, Al, Mg and Na) commonly found in soils. Using a LiBO₂ and Li₂B₄O₇ fusion method, synthetic standards were prepared in Al₂O₃ matrices for trace elements and SiO₂ matrices for major elements. Matrix corrections were based on loss-eliminated alpha coefficients and the sample analysis was carried out on an ‘as-received basis’. The method was validated using certified reference materials. Analytical figures of merit and the effect of the use of catch-weights are presented. The results of this study demonstrate that this ED-P-XRF method is suitable for the as-received analysis of contaminated soils for the determination of low parts-per-million level contaminant elements and percent level major elements.     

Microstructural characterisation of five simulated archaeological copper alloys using light microscopy, scanning electron microscopy, energy dispersive X-ray microanalysis and secondary ion mass spectrometry

This paper describes the microstructural characterisation of five simulated archaeological copper alloys, produced by modern powder technology. The chemical composition of the examined bronzes covers the major families of archaeological bronzes from antiquity until the Roman period. Light microscopy (LM), energy dispersive X-ray microanalysis (EDX), scanning electron microscopy (SEM) as well as two- and three-dimensional secondary ion mass spectrometry (SIMS) have been used to describe the main properties of the alloys. The results show a heterogeneous microstructure on a micrometer scale, formed by metallic and non-metallic phases. The latter are conglomerates of oxides or sulphides of major or minor elements.     

137Cs dating of lake cores from the Nahuel Huapi National Park, Patagonia, Argentina: Historical records and profile measurements

Historical records of short lived (¹⁴⁰Ba, ¹³¹I, ¹⁰³Ru and ⁹⁵Zr+⁹⁵Nb) and long-lived (¹³⁷Cs and ⁹⁰Sr) fission products by fallout measurements performed in Argentina since 1959 were analyzed in order to define the main characteristics of ¹³⁷Cs fallout time evolution in the Nahuel Huapi National Park, Patagonia, Argentina. Sedimentary cores were sampled from Lake Nahuel Huapi and Lake Morenito, which are located within Nahuel Huapi National Park. ¹³⁷Cs specific activity profiles were measured and ²¹⁰Pb dating was performed in each core. The time evolution of ¹³⁷Cs fallout shows different characteristics than records taken in the Northern Hemisphere.¹³⁷Cs specific activity profiles of the cores studied reproduce the fallout time sequence observed in the historical records, and the chronology obtained shows excellent agreement with ²¹⁰Pb dating.     

An efficient combined procedure for the extreme trace analysis of gold, platinum, palladium and rhodium with the aid of graphite furnace atomic absorption spectrometry and total-reflection X-ray fluorescence analysis

Summary The determination of Au, Pt, Pd and Rh at ng- and pg-levels in manganese crust, natural water and geological and biological standards is based upon extraction of these elements with Se via a coprecipitation technique, elaborated as a micro-technique. All steps of the combined procedure are controlled by radiotracer (¹⁹⁵Au) and yields vary between 90 and 100%. Zeeman graphite furnace atomic absorption spectrometry and total reflection X-ray spectrometry are employed as determination steps. Sources of systematic errors are discussed.

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Leistungsfähiges Kombinationsverfahren zur Ultraspurenanalyse von Au, Pt, Pd und Rh mit Hilfe der GF-AAS und der Totalreflexions-Röntgenfluorescenzanalyse

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Dedicated to Prof. Dr. F. Huber on the occasion of his 60th birthday     

Characterization of the impurity profile at the SiO2/Si interface using a combination of total reflection X-ray fluorescence spectrometry and successive etching of silicon

During the fabrication process of integrated circuits, dopant atoms segregate to energetically favorable sites at the interface between silicon and silicon dioxide. Because of the continuously shrinking device dimensions, this effect becomes even more significant. To describe it quantitatively within the framework of Technology Computer-Aided Design, the concentration profile at and near the SiO₂/Si interface has to be characterized accurately. Total Reflection X-ray Fluorescence Spectrometry (TXRF) with successive etching was used to determine the impurity profile at the SiO₂/Si interface with a resolution on the order of a nanometer.