X‐ray fluorescence analysis of sludge ash from sewage disposal plant

Glass bead/x‐ray fluorescence spectrometry of the sludge incineration ashes generated in sewage processing was developed for the determination of ten major components (Na₂O, MgO, Al₂O₃, SiO₂, P₂O₅, K₂O, CaO, TiO₂, MnO, Fe₂O₃) and five minor elements (Zn, Cu, Cr, As, Pb). Sewage sludge ashes consisted of rock‐forming minerals and phosphate crystals that had been used for phosphorus removal. Ash samples were melted and molded with lithium tetraborate to 35 mm diameter glass disks in a Pt–Au crucible. Analytical results of ten major components and five minor elements agreed well with the recommended values of a phosphate rock standard reference material (NIST SRM 694). Elemental compositions of sewage sludge ash from seven sewage‐processing plants in Japan were determined using this method. Concentrations of Fe₂O₃, SiO₂, and CaO, along with loss of ignition in sewage sludge ash mutually differed among the sewage‐processing plant products. Seasonal variations in concentrations of ten major components and five minor components of ash samples produced from October 2001 to September 2002 were determined using the proposed method. Concentrations of SiO₂increased with the inflow of gravel by rainfall, thereby decreasing concentrations of P₂O₅ originating from excreta and microorganisms. Copyright © 2008 John Wiley & Sons, Ltd.     

X‐ray tube spectral measurement method for quantitative analysis of X‐ray fluorescence analysis

Lα and Lβ X‐ray fluorescence spectra of a lead metallic sheet were measured using an energy dispersive X‐ray spectrometer by changing the X‐ray tube voltage and the material of the primary filter. The Lα to Lβ intensity ratio changed from Lα: Lβ = 3: 1 at 15 kV to Lα: Lβ = 1: 1 at 50 kV depending on the X‐ray tube voltage and the filter. The scattered X‐ray spectra of an acrylic slab instead of the sample in the sample holder were measured by changing the applied voltage and the material of the primary filter. The calculated values of the Pb Lα/Lβ intensity ratio of the metallic sheet using the Shiraiwa–Fujino formula by inserting the scattered X‐ray spectra of an acrylic plate as incident X‐ray spectra and the fundamental parameters taken from the Elam database were in good agreement with the experimental ones. We conclude that we can obtain an incident X‐ray spectrum approximately by measuring the scattered X‐ray spectrum without measuring the direct incident beam. Copyright © 2010 John Wiley & Sons, Ltd.     

X‐ray fluorescence analysis with a pyroelectric x‐ray generator

Several types of handy x‐ray fluorescence spectrometers are presented. The results obtained with a Niton spectrometer are presented as a goal to develop a laboratory‐made spectrometer using an Amptek Cool‐X pyroelectric x‐ray generator. A small and cheap charge‐up x‐ray emitting device and its spectrum are also presented. Handy x‐ray spectrometers are now progressing rapidly and the detection limits are in the range of a few ppm for certain elements. Copyright © 2005 John Wiley & Sons, Ltd.     

Characterization of ashes from greenhouse crops plant biomass residues using X‐ray fluorescence analysis and X‐ray diffraction

A characterization of ashes obtained by thermal treatments on greenhouse crops plant biomass residues is presented. The chemical analysis, by X‐ray fluorescence (wavelength‐dispersive X‐ray fluorescence), and phase analysis, by X‐ray diffraction, of the resultant ashes are reported. Thermal treatments of selected samples of these residues increase the relative amounts of inorganic Mg, Si, P, and S in the ashes, being these amounts as high as increasing temperature. As an opposite effect, Na, Cl, and K contents decrease as increasing temperature by a volatilization process of the chlorides, as confirmed by X‐ray diffraction. The crystalline phase analysis of the ashes demonstrates the formation of inorganic constituents of the biomass, including alkaline chlorides and calcium salts (calcite, anhydrite, and apatite). Progressive thermal treatments induce the formation of new silicate phases (akermanite and grossularite) and silica (α‐quartz and cristobalite). Furthermore, the particle size of the starting biomass samples does not influence the evolution of the crystalline phases by thermal treatments. In contrast, a previous leaching using water and subsequent heating at 1,000 °C produces the formation of periclase (MgO), lime (CaO), and the silicate gehlenite, without the presence of anhydrite. This study is interesting for future investigations on the residues as a profitable biomass source for energy production and sustainable large‐scale management. Some potential applications of the resultant ashes can be proposed.     

Analysis of engine motor oils by X‐ray absorption and X‐ray fluorescence spectroscopies

The molecular structure of lubricating motor oils is investigated by X‐ray absorption fine structure spectroscopy measurements. Both fresh and used oils are studied. Although the Zn K‐edge spectra gave information about the degradation of the antiwear/antioxidant zinc dialkyl dithiophosphate (ZDDP) additives within the oil, Fe K‐edge spectra are representatives for iron species dispersed in the oil during operation at elevated temperatures and pressures in the engine. The detailed analysis of the measured data shows that substantial differences are detectable in the spectra of the fresh and used oil. Our results show that the Zn–S bonds of the ZDDP are decomposed during the operation, resulting in Zn–O bonds instead. Furthermore, sixfold Fe–O bonds similar to those in Fe₂O₃ are found within the used oil, suggesting the presence of debris from the antiwear film of lubricated motor parts in the used oil. Copyright © 2014 John Wiley & Sons, Ltd.     

Simultaneous X‐ray fluorescence and scanning X‐ray diffraction microscopy at the Australian Synchrotron XFM beamline

Owing to its extreme sensitivity, quantitative mapping of elemental distributions via X‐ray fluorescence microscopy (XFM) has become a key microanalytical technique. The recent realisation of scanning X‐ray diffraction microscopy (SXDM) meanwhile provides an avenue for quantitative super‐resolved ultra‐structural visualization. The similarity of their experimental geometries indicates excellent prospects for simultaneous acquisition. Here, in both step‐ and fly‐scanning modes, robust, simultaneous XFM‐SXDM is demonstrated.     

X‐ray fluorescence analysis applied to geochemistry of quartz in Argentina

The growing demand for high‐purity quartz in the international market led to the systematic investigation of the geochemical quality of this mineral in deposits Argentina. This study is a contribution to the scarce information on the geochemistry of quartz in Argentina. A total of 525 multielemental chemical analyses were performed with XRF spectrometry in less than 3 months. SiO₂ concentration was calculated by difference from XRF impurity determinations. As a result of this study, 36 sites over 141 sampled deposits were identified as being of desirable quality. Low‐Z oxides, considered critical impurities for quartz, were determined by atomic absorption spectrometry, only in samples of these selected sites, because of high XRF detection limits. The analytical results allowed the classification of the quality of quartz according to its environment and geological genesis. It could be determined that better purity quartz corresponds to veins far away from the Achala and Alpa Corral batholith and occurs in metamorphic rocks, followed by pegmatitic quartz from inside the batholith and lastly by quartz of well‐known hydrothermal origin. Copyright © 2004 John Wiley & Sons, Ltd.     

X‐ray fluorescence spectrometry in Dar es Salaam

Energy‐dispersive x‐ray fluorescence (EDXRF) analysis has been established at the University of Dar es Salaam, Faculty of Science, Department of Physics. Calibration was conducted using thin films from Micromatter (USA) for secondary target XRF. We report on the performance of the spectrometer including the detection limits attained, which range from 0.01 to 10 ng cm^?2 using collimators of 6 and 8 mm diameter under excitation conditions of 50 kV, 35 mA. The accuracy of the measurements was checked using IAEA SOIL‐7 and NIST 3087a Certified Reference Materials. The experimental values differed by <5% from the certified values. The total reflection x‐ray fluorescence (TXRF) facility added as a module to the existing XRF system provides detection limits between 0.1 and 100 pg for most of the elements measured. Copyright © 2005 John Wiley & Sons, Ltd.     

Application of X‐ray fluorescence to turbulent mixing

Combined measurements of X‐ray absorption and fluorescence have been performed in jets of pure and diluted argon gas to demonstrate the feasibility of using X‐ray fluorescence to study turbulent mixing. Measurements show a strong correspondence between the absorption and fluorescence measurements for high argon concentration. For lower argon concentration, fluorescence provides a much more robust measurement than absorption. The measurements agree well with the accepted behavior of turbulent jets.     

Combined X‐ray diffraction and alpha particle X‐ray spectrometer analysis of geologic materials

The shallow interrogation depth of the lightest elements (Na, Mg, Al, and Si) detected by the particle‐induced X‐ray emission branch of the Curiosity Rover's alpha particle X‐ray spectrometer suggests that the X‐rays of these elements very likely emerge from a single mineral grain. This reality violates the assumption of atomic homogeneity at the micron scale made in both existing spectrum‐reduction approaches for the alpha particle X‐ray spectrometer. Consequently, analytical results for these elements in igneous geochemical reference materials exhibit deviations from certified concentrations in a manner that can be related to the total alkali‐silica diagram. A computer code is introduced here to provide quantitative prediction of these deviations using the mineral abundances determined from X‐ray diffraction. The latter are converted to area coverage fractions to represent the sample surface, and a fundamental parameters computation predicts the elemental X‐ray yields from each mineral and sums these. In this process, the chemistry of each individual mineral has to be varied by an iterative simplex approach; X‐ray yields are computed and compared with the peak areas from the fit of the bulk sample. When the difference between mineral yields and peak areas for each element are minimized, the mineral formulae are set and elemental X‐ray yields provided. The ratio between the summed mineral X‐ray yields and the corresponding yields based on the homogeneity assumption may then be compared directly with the concentration deviations measured in our earlier work. For several rock types, good agreement is found, thereby consolidating our understanding of the effects of sample mineralogy on alpha particle X‐ray spectrometer results. Copyright © 2017 John Wiley & Sons, Ltd.     

Elemental depth profiling with a wire in microbeam X‐ray fluorescence analysis

This study proposes simple techniques involving the use of a thin wire set close to the sample surface to measure the elemental depth distribution in microbeam X‐ray fluorescence analysis. One is the X‐ray fluorescence detection in energy‐dispersive mode using a solid‐state detector in combination with the sample movement, and the other is in projection mode using an X‐ray charge‐coupled device camera. The minimum depth resolution (spatial resolution) obtained with a thin Mo wire is about 15 µm. Compared with a confocal depth‐profiling method, wire depth‐profile analysis is easy to implement, flexible, and has reasonable sensitivity. Copyright © 2011 John Wiley & Sons, Ltd.     

Trace element determinations in uranium by total reflection X‐ray fluorescence spectrometry using polychromatic X‐ray excitation

Suitability of polychromatic X‐rays has been assessed for the total reflection X‐ray fluorescence (TXRF) trace elemental determinations in aqueous solutions as well as uranium oxide certified reference materials. The method involves total reflection of X‐rays below a certain energy level on the TXRF sample support and exciting the analytes present in ng amount on these supports, measuring the TXRF spectra, processing the spectra, and finally determining the elemental concentrations. For uranium‐based samples, the samples were dissolved, main matrix uranium was separated from these solutions using solvent extraction, and trace elements were determined using aqueous phase following above approach. The method is simple and easier to implement compared with the monochromatic excitation but has similar or in some cases better detection limits compared with those obtained using monochromatic excitation. The details of the methodology, quality of analytical results, and detection limits are described and compared with those obtained using monochromatic excitation. Copyright © 2017 John Wiley & Sons, Ltd.     

Background estimation based on Fourier Transform in the energy‐dispersive X‐ray fluorescence analysis

This paper discusses a new method of background estimation in the energy‐dispersive X‐ray fluorescence (EDXRF) analysis, which is based on Fourier Transform (in this paper, we call it Fourier Transform background estimation method). Compared with the Sensitive Nonlinear Iterative Peak method, the new method has the feature of FWHM independence. It has been proved that a background can be estimated automatically and accurately by the new method in the synthesized spectrum and the spectra from measurement. Fourier Transform background estimation method can estimate the background accurately in the EDXRF spectrum using an X‐ray tube source. Copyright © 2011 John Wiley & Sons, Ltd.     

Integrating 3D images using laboratory‐based micro X‐ray computed tomography and confocal X‐ray fluorescence techniques

The application of non‐destructive imaging to characterizing samples has become more important as the costs of samples increase. Imaging a sample via X‐ray techniques is preferable when altering or even touching the sample affects its properties, or when the sample is fielded after characterization. Two laboratory‐based X‐ray techniques used at Los Alamos include micro X‐ray computed tomography (MXCT) and confocal micro X‐ray fluorescence (confocal MXRF). Both methods create a 3D rendering of the sample non‐destructively. MXCT produces a high‐resolution (sub‐µm voxel) rendering of the sample based upon X‐ray absorption; the resulting model is a function of density and does not contain any elemental information. Confocal MXRF produces an elementally specific 3D rendering of the sample, but at a lower (30 × 30 × 65 µm) resolution. By combining data from these two techniques, scientists provided a more comprehensive method of analysis. We will describe a MATLAB routine written to render each of these data sets individually and/or within the same coordinate system. This approach is shown in the analysis of two samples: an integrated circuit surface mounted resistor and a machined piece of polystyrene foam. The samples chosen provide an opportunity to compare and contrast the two X‐ray techniques, identify their weaknesses and show how they are used in a complementary fashion. Copyright © 2010 John Wiley & Sons, Ltd.     

Activities in the IAEA X‐ray fluorescence laboratory at Seibersdorf

This paper describes the specific philosophy behind the functioning of the IAEA XRF Laboratory at Seibersdorf and its role in the XRF community. Some examples of the research and development activities and the results obtained are given. They include methodological development and construction of XRF instruments in order to extend the applicability range of the XRF technique, particularly in support of applications of the analytical technique in developing IAEA member states. The contribution of the laboratory to the training in methodology and applications of XRF techniques and to development of QA/QC procedures is also emphasised. Copyright © 2006 John Wiley & Sons, Ltd.     

Correcting for surface topography in X‐ray fluorescence imaging

Samples with non‐planar surfaces present challenges for X‐ray fluorescence imaging analysis. Here, approximations are derived to describe the modulation of fluorescence signals by surface angles and topography, and suggestions are made for reducing this effect. A correction procedure is developed that is effective for trace element analysis of samples having a uniform matrix, and requires only a fluorescence map from a single detector. This procedure is applied to fluorescence maps from an incised gypsum tablet.     

Chemical analysis of very small‐sized samples by wavelength‐dispersive X‐ray fluorescence

The chemical characterisation of very small‐sized samples is often of major interest in forensic analysis, studies of artworks, particulate matter on filters, raw materials impurities, and so on, although it generally poses considerable problems owing to the difficulty of obtaining precise and accurate results. This study was undertaken to develop a set of methods for the chemical characterisation of very small‐sized samples by wavelength‐dispersive X‐ray fluorescence. To conduct the study, sample preparation (as beads and pellets) and measurement conditions were optimised to reach the necessary detection and quantification limits and to obtain the appropriate measurement uncertainty for characterising the types of materials involved. The measurements were validated by using reference materials. Three test methods were developed. In two methods, the samples were prepared in the form of beads (one method being for geological materials and the other for the analysis of nongeological materials such as particulate matter on filters, glasses, frits, and ceramic glazes and pigments). In the third method, the samples were prepared in the form of pellets for the analysis of volatile elements in geological materials. In the three methods, detection limits, quantification limits and measurement uncertainties were obtained similar to those found when a bead or pellet is prepared by the usual methods from 0.5 g sample. However, in this study, sample size was between 30 and 40 times smaller in the case of beads and 100 times smaller in the case of pellets, thus broadening the range of possible wavelength‐dispersive X‐ray fluorescence applications in the chemical characterisation of materials. Copyright © 2012 John Wiley & Sons, Ltd.     

Use of synchrotron radiation X‐ray fluorescence and X‐ray absorption spectroscopy to investigate bioaccumulation,molecular target,and biotransformation of volcanic elements

Because environment pollutants have a strong impact on ecosystems, including human health, methods of their determination and mitigation have received special attention in recent years. Taking advantage of the wide range of data that can be obtained by synchrotron radiation X‐ray fluorescence spectroscopy (SRXRF) in the field of environmental sciences, different instrumental setups were used to study the biological fates of toxic elements in volcanic environments. The elemental composition of plants, algae, and bacteria in Copahue and Domuyo volcanoes from Argentinean Patagonia was determined by SRXRF and the volcanic elements Ti, Fe, and Zn were abundant in these organisms. Interestingly, a high As concentration was found in cyanobacteria (26.2 μg/g) living in As contaminated stream (250 μg/ml). Because arsenic is toxic and human carcinogen, element‐retention capacity, element‐protein associations, and arsenic metabolism in this As resistant organism were analyzed by SRXRF. A high capacity (100–95%) of Ti > Fe > Cr > Sr > Ni > Cu > Mn > Zn > As retention was found after aqueous/alcoholic extraction assisted by ultrasonication. The cyanobacterial proteins were separated by SDS‐PAGE, electro‐transferred to nitrocellulose, and mapped by SRXRF. Defined protein bands containing Ca, Ti, Mn, Fe, and/or Zn were observed. Their ability to metabolize arsenic was revealed by combining SRXRF and X‐ray absorption near edge spectroscopy and Dimethylarsenic was found. Based on results, we speculate that these cyanobacteria could be interesting candidates for water treatment. Finally, we conclude that SRXRF is a valuable tool to study the biological cycle of environmental pollutants, including their accumulation, molecular targets, and metabolism. The SRXRF may also assist in remediation researches.     

X‐ray absorption and x‐ray fluorescence for the characterization of titanium oxide‐modified HPLC silicas

Titanium oxide grafted on to the surfaces of chromatographic silica was investigated by x‐ray fluorescence (XRF) and x‐ray absorption (XAS) spectroscopy and the latter used before and after the extensive use of this material as a support for reversed‐phase high‐performance liquid chromatography (RP‐HPLC). XRF indicated the formation of a complete 2:1 monolayer whereas XAS suggested the presence of more than one titanium oxide structure. These structures show some slight modification after immobilization of PMOS and use in HPLC. Copyright © 2005 John Wiley & Sons, Ltd.