Preparation of arsenic‐containing white rice grains as calibration standards for X‐ray fluorescence analysis of total arsenic in cereals

A preparation method of arsenic‐containing white rice grains as calibration standards was developed for the X‐ray fluorescence (XRF) analysis of arsenic in rice grains. Calibration standards were prepared by adding 10 g of white rice grains (from Japan) to 100 ml methanol‐containing dimethylarsinic acid corresponding to 2–100 µg arsenic. The mixture was heated, dried at 150 °C, cooled to room temperature, and then stored in a silica gel desiccator. A total of 5.0 g of each calibration standard was packed into a polyethylene cup (32 mm internal diameter and 23 mm height) covered with a 6‐µm‐thick polypropylene film and then analyzed by wavelength‐dispersive XRF spectrometry. The calibration curve for arsenic obtained from the white rice grains containing arsenic showed good linearity over a concentration range of 0.21–5.00 mg kg^?1 arsenic. The limit of detection of arsenic was 0.080 mg kg^?1. To check the reliability of the XRF method, the concentrations of arsenic in six samples of grain cereals and two samples of flour were compared with those obtained by atomic absorption spectrometry after acid decomposition. The values obtained by both analytical methods showed good agreement. Copyright © 2016 John Wiley & Sons, Ltd.     

X‐ray fluorescence analysis of Cr,As, Se,Cd, Hg,and Pb in soil using pressed powder pellet and loose powder methods

Quantitative analyses of Cr, As, Se, Cd, Hg, and Pb in soil were performed using wavelength dispersive X‐ray fluorescence (WDXRF) spectrometry with pressed powder pellet and loose powder methods. Standard soil samples containing hazardous metals were prepared by adding appropriate amounts of aqueous standards to base soils and then drying and homogenizing them. Base soil powders ground to less than 12.5 µm of modal particle size were Tachikawa loam, brown forest soil, and weathered granite containing 17.9, 9.43, and 3.49 mass% of Fe₂O₃, respectively. Analytical lines were CrKα, AsKα, SeKα, CdKα, HgLα, and PbLβ, with accompanying corrections for overlapping of SeKβ to PbLβ and PbLα to AsKα. Specimens for XRF analysis were prepared using powder pellets pressed to 23 mm internal diameter of an Al ring with 300 kgf cm^?2, and loose powder in a 31 mm internal diameter polyethylene cup covered with 6‐µm thickness of polypropylene film. Calibration curves drawn using the proposed standards showed good linearity under 3000 mg kg^?1 for the five metals, and 300 mg kg^?1 for Hg. Corrections with Compton scattering for AsKα, SeKα, CdKα, HgLα, and PbLβ, and with background scattering for CrKα were effective and produced identical inclinations of calibration curves. CdKα having larger critical depth in the loose powder specimen showed merely smaller inclination of calibration curve than that of the pressed powder specimen because of optical shading. The spike test for five analytes showed good recovery for gravel soil and pumice soil. Copyright © 2009 John Wiley & Sons, Ltd.     

X‐ray fluorescence analysis of Co,Ni, Pd,Ag, and Au in the scrapped printed‐circuit‐board ash

A method for the quantitative analysis of Co, Ni, Pd, Ag, and Au in the scrapped printed‐circuit‐board ash by X‐ray fluorescence (XRF) spectrometry using loose powder was developed. The printed‐circuit‐board samples were converted to ash pyrolytically in porcelain crucibles by sequential heating using a gas burner and electric furnace, and then were ground with a ball mill. The calibrating standards were prepared by adding the appropriate amounts of NiO powder and aqueous standard solutions containing Co, Pd, Ag, and Au to the base mixtures of Al₂O₃ (5.0 mass%), SiO₂ (49 mass%), CaCO₃ (11 mass%), Fe₂O₃ (3.3 mass%), and CuO (30 mass%) as a matrix. Then, 10 g of the resulting mixtures were dried and homogenized for 90 min with a V‐type mixing machine. Specimens for XRF analysis were prepared from the so‐called loose‐powder method in which powder samples were compacted into a hole (12.0‐mm diameter and 5.0‐mm height) in an acrylic plate and covered with a 6‐µm thickness of polypropylene film. Matrix effects were corrected using the intensity value of Compton scattering for PdKα, AgKα, and AuLβ₂, and that of background scattering at 35.8° (2θ) for CoKα and NiKα. The detection limits corresponding to three times the standard deviation of the blank intensity were 2.5–45 µg g^?1. The proposed method was validated against the pressed‐powder‐pellet method by comparing the calibration curves. Moreover, the concentrations of Co, Ni, Pd, and Ag determined using the proposed XRF method were approximately the same as those resulting from an atomic‐absorption‐spectrometric analysis. Copyright © 2013 John Wiley & Sons, Ltd.     

Loose‐powder technique for X‐ray fluorescence analysis of ancient pottery using a small (100 mg) powdered sample

A molded‐loose‐powder technique using a small powdered sample (100 mg) was developed for the X‐ray fluorescence analysis of 22 components (Na₂O, MgO, Al₂O₃, SiO₂, P₂O₅, K₂O, CaO, TiO₂, MnO, Fe₂O₃, V, Cr, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, and Pb) in ancient pottery. This loose powder specimen was prepared by pressing the small powdered sample into a sample holder, formed from a stainless steel disk (48‐mm diameter × 0.8‐mm height) with a hole (11‐mm diameter), by hand. Calibration standards were prepared by homogenizing chemical reagents containing these 22 analytes using the concentration ranges of 166 ancient potteries and three clay materials from Japan. The calibration curves of these benchmark mixtures exhibited a good linearity (correlation coefficient, r = 0.990–1.000), accuracy, and reproducibility compared with those of other synthesized specimens and three reference standards. The lower limits of detection were less than tens of mg kg^?1 (e.g., 94 mg kg^?1 for Na₂O, 11 mg kg^?1 for P₂O₅, 1.1 mg kg^?1 for Rb, and 0.9 mg kg^?1 for Y). Using the present method, we determined 22 components in two prehistoric potteries from Japan. The advantage of this method is that only a small amount of sample is required, which can be prepared easily and rapidly and reused for other analyses. Copyright © 2012 John Wiley & Sons, Ltd.     

Assessment of natural radioactivity in rice and their associated population dose estimation

ABSTRACT

The concentration of natural radioactivity in rice is an important parameter for the determination of population exposure by the ingestion of natural radionuclides during habitual consumption of food. All types of food including rice contain a detectable amount of natural radioactivity which successively relocate into the human body via the ingestion pathway. Rice is the main cultivated crop in Bangladesh and most of the Bangladeshi people consume rice as their staple food. Hence, studies on the evaluation of natural radioactivity in rice have been performed by gamma-ray spectrometry using High Purity Germanium (HPGe) detector in order to estimate various radiation hazards due to rice consumption. The average activity levels of natural radionuclides ²²⁶Ra, ²²⁸Ra and ⁴⁰K in the rice samples were 1.09?±?0.31, 0.17?±?0.21 and 4.70?±?1.59?Bq?kg^?1, respectively. The estimated effective doses for the respective radionuclides caused by the rice consumption were 43.69, 16.39 and 4.15?µSv?y^?1, respectively which was below the UNSCEAR compiled value. The calculated excess lifetime cancer risk (ELCR) values via rice consumption were found below the acceptable limit of 0.29?×?10^?3 for radiological risk.     

A miniature X‐ray tube approach to measuring lead in bone using L‐XRF

Using a miniature X‐ray tube and silicon PiN diode detector, an approach to measuring lead (Pb) in bone phantoms was tested. The X‐ray tube was used to excite L‐line X‐ray fluorescence (L‐XRF) of lead in bone phantoms. The bone phantoms were made from plaster of Paris and dosed with varying quantities of lead. Phantoms were made in two sets with different shapes to model different bone surfaces. One set of bone phantoms was circular in cross‐section (2.5‐cm diameter), the other square in cross‐section (2.2 cm × 2.2 cm). Using an irradiation time of 180 s (real time), five trials were run for each bone phantom. Analysis was performed for both Lα and Lβ lead X‐rays. Based on these calibration trials, (3σ₀/slope) minimum detection limits of 7.4 ± 0.3 µg Pb g^?1 (circular cross‐section) and 8.6 ± 0.6 µg Pb g^?1 (square cross‐section) were determined for the bare bone phantoms. To simulate a more realistic in vivo scenario with soft tissue overlying bone, further trials were performed with a resin material placed between the experimental system and the bone phantom. For the square cross‐section bone phantoms, a layer of resin with a thickness of 1.2 mm was used, and a minimum detection limit of 17 ± 3 µg Pb g^?1 determined. For the circular cross‐section phantoms, a layer of resin with an average thickness of 2.7 mm was used. From these, a more realistic minimum detection limit for in vivo applications (43 ± 7 µg Pb g^?1) was determined. Copyright © 2011 John Wiley & Sons, Ltd.     

Quantitative analysis of chromite ores using glass discs in moderate dilutions of lithium tetraborate by x‐ray fluorescence spectrometry

A method for the quantitative analysis of chromite ores by x‐ray fluorescence spectrometry using beads is proposed. The work concerned the serious problems caused by the refractory nature of these materials which prevents the use of glass discs in x‐ray fluorescence. An in‐depth study was done to optimise the variables which influence the glass disc formation process. Sufficiently homogeneous glass discs were obtained under the following experimental conditions: lithium tetraborate as flux with moderate sample dilution (1:40), with the addition of one or two drops of LiBr solution(250 g l^?1), at a temperature of 1200 °C for 30 min. The qualitative and semiquantitative results for the chromite ores provided synthetic standards based on combinations of similar reference materials and different pure ignited oxides. These standards were used to obtain the calibration curves for Cr, Si, Al, Fe, Ti, Ca, Mn, Mg, Na and K oxides, with root mean square error always below 0.357. The calibration curves were used in the quantitative analysis of chromite ores with satisfactory accuracy, justifying compensation of the interelemental effects. The suggested method is an efficient solution to the problems with the quantitative analysis of this type of material by XRF. Copyright © 2006 John Wiley & Sons, Ltd.     

Transportable EDXRF analysis of environmental water samples using Amberlite IRC748 ion‐exchange preconcentration

Transportable energy‐dispersive X‐ray fluorescence spectrometers allow on‐site assessment of metal‐contaminated soils, sediments and other solids. Multi‐element analysis of liquid samples, such as surface water, groundwater, acid leach and aqueous soil extracts, would enhance on‐site environmental assessments. However, transportable spectrometers typically have detection limits for metals in waters of approximately 1–10 mg l^?1, whereas many toxic elements are regulated at concentrations of 1–100 µg l^?1. If detection limits for this technique can be lowered, then only one analytical tool, a transportable XRF spectrometer, may be sufficient for remote areas, increasing program flexibility and reducing the amount of equipment that needs to be purchased, transported and operated. This research develops an in‐field preconcentration technique using Amberlite IRC748 cation‐exchange resin, followed by XRF analysis of Fe, Ni, Cu, Zn and Pb at µg l^?1 concentrations in aqueous samples. The operational parameters tested to maximise analyte recovery included flow rate, and the mass and chemical form of the resin. The method was tested with extracts from landfill soils and surface waters from a derelict base metal mine. The method recovered Cu, Zn and Pb accurately, and Ni and Fe at concentrations satisfactory for screening purposes. Copyright © 2010 John Wiley & Sons, Ltd.     

A risk assessment study of heavy metals in ambient air by WD‐XRF spectrometry using aerosol‐generated filter standards

A risk assessment study of the air quality in the surrounding of roads covered with slags coming from the non‐ferrous metal industry was performed. A monitoring campaign was carried out at three locations in Flanders by collecting the PM10 fraction and the total suspended particulates (TSP) of the airborne dust particles, entrapping heavy metals, on membrane filters. The heavy metal concentration on the dust filters was determined by wavelength‐dispersive x‐ray fluorescence (WD‐XRF) spectrometry. The XRF calibration curves were set up with filter standards prepared in the laboratory using an aerosol‐generated loading system. The acquired WD‐XRF results were confirmed by inductively coupled plasma atomic emission spectrometric (ICP‐AES) measurements after acid digestion on a selected number of filters. Electron probe microanalysis (EPMA) confirmed that aerosol‐loaded filter standards and dust filters with a concentration level of the analyzed element below 3300 ng cm^?2 were homogeneously distributed. Dust filters with higher concentrations, and especially filters loaded with the TSP fraction, reflected an inhomogeneous distribution of the analyzed element on the filter. The WD‐XRF analytical results acquired in the monitoring campaign revealed that the concentration of Pb on the dust filters never exceeded the immission standard (yearly average) of 2000 ng m^?3. It can be stated that the impact on human health is limited and can still be reduced by covering the polluted roads with a layer of asphalt. Further evaluation of soil and water samples from the nearby surroundings reveals that the heavy metal content in the slags makes an important contribution to environmental pollution, especially the contamination of groundwater. Copyright © 2003 John Wiley & Sons, Ltd.     

Determination of Cr(III) and Cr(VI) in water by wavelength‐dispersive X‐ray fluorescence spectrometry after preconcentration with an ion‐exchange resin disk

A rapid and simple method using an ion‐exchange resin disk combined with wavelength‐dispersive X‐ray fluorescence (WDXRF) spectrometry was developed for the determination of Cr(III) and Cr(VI) in water. A 100‐ml water sample was first adjusted to pH 3 with nitric acid and then passed through an anion‐exchange resin disk placed on top of a cation‐exchange resin disk at a flow rate of 1 ml min^?1 to separate Cr(III) and Cr(VI). Anionic Cr(VI) was preconcentrated on the upper anion‐exchange resin disk, whereas cationic Cr(III) was preconcentrated on the lower cation‐exchange resin disk. Each ion‐exchange resin disk was dried at 100 °C for 30 min in an electric oven and coated with a commercially available laminate film. The specimens were measured using a WDXRF spectrometer. The calibration curves of Cr(III) and Cr(VI) showed good linearity in the range 1–10 µg. The detection limits corresponding to three times the standard deviation (n = 5) of blank values were 0.17 µg for Cr(III) and 0.16 µg for Cr(VI). If a 1‐l water sample is used, these limits would be 0.17 and 0.16 µg l^?1, respectively. A spike test for 50 µg l^?1 Cr(III) and Cr(VI) in tap water and river water showed quantitative recoveries (94–114%), although this was not observed for mineral drinking water owing to the overlap of V Kβ with Cr Kα. The recovery after overlap correction was satisfactory (115%). Copyright © 2011 John Wiley & Sons, Ltd.     

X‐ray fluorescence analysis of trace metals in environmental water using preconcentration with an iminodiacetate extraction disk

A simple and convenient x‐ray fluorescence analysis procedure for trace amounts of Mn, Fe, Co, Ni, Cu, Zn, Cd, Hg and Pb in water was developed using preconcentration with an iminodiacetate extraction disk (IED). The IED was coated on both faces with commercially available laminate film to prevent x‐ray damage to the IED by strong x‐irradiation (4 kW; 50 kV, 80 mA) of the wavelength‐dispersive x‐ray fluorescence spectrometer. Lamination of the IED prolongs its life from 7 to about 200 min at 4 kW irradiation while negligibly decreasing the x‐ray fluorescence. Lowering the power of primary x‐rays to less than 1.5 kW compensated for the Hg evaporation. Linear calibration curves were obtained over the range 500 µg–5 mg for Mn, Fe, Co, Ni, Cu, Zn, Cd, Hg and Pb. Detection limits corresponding to three times the standard deviation of the blank intensity were 0.1–0.4 µg for Mn, Co and Ni, 0.5–0.8 µg for Fe, Cu, Zn and Pb and 7 µg for Cd. A spike test for 10 µg of eight analytes, excluding Mn, showed good recoveries (90–100%) for city water and rainwater. Analytical results for municipal tap water and rainwater agreed well with values obtained using atomic absorption spectrometry. Copyright © 2006 John Wiley & Sons, Ltd.     

Methodology for the determination of minor and trace elements in petroleum cokes by wavelength‐dispersive X‐ray fluorescence (WD‐XRF)

This article describes a methodology for the analysis of minor and trace elements in petroleum cokes by wavelength‐dispersive X‐ray fluorescence (WD‐XRF) spectrometry. The methodology was developed in order to have a rapid and reliable control method of these elements, because they determine coke end uses. There are a number of standard methods of chemical analysis by WD‐XRF or inductively coupled plasma atomic emission spectrometry (ICP‐OES) techniques. However, the standards that use WD‐XRF measurement give detection limits (L_D) above 10 mg·kg^?1 and only analyse a few elements of interest, whereas the ICP‐OES method requires extensive sample handling and long sample preparation times, with the ensuing errors. In order to improve the method described in the standard ASTM D6376 and reach the L_D and quantification limits (L_Q) required, the different stages of the process, ranging from sample preparation to measurement conditions: analytical line, detector, crystal, tube power, use of primary beam filters, and measurement time, were optimised. The samples were prepared in the form of pressed pellets, under conditions of high cleanliness of the mills, crushers, presses, and dies, and of the laboratory itself. The following reference materials were used in measurement calibration and validation: SRM 1632c, SRM 2718, SRM 2719, SRM 2685b, AR 2771, AR 2772, SARM 18, SARM 19, and CLB‐1. In addition, a series of materials were analysed by WD‐XRF and ICP‐OES, and the results were compared. The developed methodology, which uses WD‐XRF, is rapid and accurate, and very low L_D and measurement uncertainties were obtained for the following elements: Al, Ba, Ca, Cr, Cu, Fe, Ge, K, Mg, Mn, Mo, Na, Ni, P, Pb, S, Sb, Se, Si, Sn, Sr, Ti, V, and Zn. Copyright © 2010 John Wiley & Sons, Ltd.     

Chemical analysis of argon–oxygen decarburization slags in stainless steelmaking process by X‐ray fluorescence spectrometry

A quantitative analysis method of fluorine in the slags produced in the stainless argon–oxygen decarburization (AOD) process by X‐ray spectrometry was proposed employing direct analysis technique by pressed pellet. This research investigated the separate quantification of calcium fluoride and calcium oxide contained in AOD slags. X‐ray diffraction measurement was performed to identify the stable phase of fluorine compound, which is primarily present in the slags. The synthetic standards prepared in laboratory were used to construct the X‐ray fluorescence (XRF) calibration curves for F, Ca_tO, SiO₂, MgO, Al₂O₃ and Cr₂O₃, considering the matrix effects and line overlap corrections (t: total). The calibration curves were tested by the quantitative analysis of synthetic standards with satisfactory precision and accuracy. The proposed method might be an alternative solution to the problem with the simple and routine chemical analyses of calcium fluoride in AOD slags of stainless steelmaking process by XRF spectrometry. Copyright © 2010 John Wiley & Sons, Ltd.     

Proton µ‐PIXE mapping,AFM imaging and size statistics of mineral granules in a dental composite

We applied proton microbeam particle‐induced X‐ray emission (µ‐PIXE) for mapping Ca, Zr, Ba and Yb, and atomic force microscopy (AFM) for imaging the surface landscape of a dental composite which releases Ca²⁺ and F^? for the protection of hard dental tissues. Three areas ～250 × 250 µm² located ～0.5–2 mm apart on a smooth surface specimen were mapped with 3.1 MeV protons focused to a ～3.0 µm spot and at ～3.9 µm pixel size sampling. The maps evidenced particles with diameters of 3.2–32 µm (Ca), 20–60 µm (Zr), ≤ 4 µm (Ba) and 10–50 µm (Yb). Cross‐section area histograms of Ca‐rich particles fitted with 2–6 Poisson functions revealed a polydisperse size distribution and substantial differences from an area to another, possibly implying large local variations of Ca²⁺ released in the hard tissue near a dental filling of a few millimeters in diameter. Such imbalances may lead to low local Ca²⁺ protection of the dental tissue, favoring the onset of secondary caries. Similarly, AFM images showed high zone‐dependent differences in the distributions of grains with apparent diameters of 1–4 µm, plausibly recognized as Ca‐ and Ba‐containing particles. In a simple model based on demineralization data, lateral diffusion of Ca²⁺ between adjacent domains containing high‐ and low‐area Ca‐rich grains is described by exponential concentration gradients. These gradients may generate appreciable electromotive forces, which may enhance electrochemically the local tissue demineralization. Similar effects are to be expected in the protective action of F^? ions released from microgranules of YbF₃ and of Ba fluoroaluminosilicate glass. Copyright © 2010 John Wiley & Sons, Ltd.     

The determination of elements in welding fume by X‐ray spectrometry and UniQuant

Welding is a hazardous process with an associated risk of health effects related to the fume arising from the core metal, flux components and welding surface. X‐ray fluorescence (XRF) is commonly used to determine elemental concentrations as part of occupational hygiene investigations using conventional calibrations. A method is proposed to determine elements in welding fume using XRF and a fundamental parameter software package known as UniQuant^®. This was found to remove the need for special dust standards being prepared as the calibration used was based on a series of standards supplied with UniQuant that would cover all sample types. A conventional calibration and UniQuant calibration were set up and elements found in welding fume were determined from tin to titanium. Samples obtained from the Health and Safety Laboratory Workplace Analysis Scheme for Proficiency (WASP) programme were also analysed by both methods for nickel, iron, manganese and chromium. For the normal calibration, average recovery results for the WASP samples were between 92 and 103% of the target value with relative standard deviations of 3‐7%. For the UniQuant calibration, average recovery results for the WASP samples were between 97 and 112% of the target value with relative standard deviations of 3‐10%. These results are well within analytical performance expectations for the type of welding fume matrix analysed. The method was applied to real welding fume samples collected from workplaces. Copyright © 2011 John Wiley & Sons, Ltd.     

Feasibility for chemometric energy dispersive X‐ray fluorescence and scattering (EDXRFS) spectroscopy method for rapid soil quality assessment

Soil quality assessment (SQA) is important for modulating agricultural productivity and thus requires simple and rapid analysis of soil (macro & micro) nutrients (here called soil quality indicators – SQIs). We report proof of concept of a chemometrics‐assisted energy dispersive X‐ray fluorescence and scattering (EDXRFS) spectroscopy technique for direct rapid analysis of SQIs. The EDXRFS method exploits, in addition to fluorescence, the X‐ray scatter peaks obtained non‐invasively from soils to develop a calibration strategy for quantitative analysis of SQIs in model clay soils doped with micronutrients (Fe, Cu, and Zn) and macronutrients (NO₃^?, SO₄^2?, and H₂PO₄^?). The soil samples and certified reference materials IAEA Soil‐7 and IAEA Soil‐1 (used to build spectral library for soil classification) were irradiated at various live times (to simulate different signal‐to‐noise ratios of analyte signals and analysis speed) in a teflon holder and were analyzed using a ¹⁰⁹Cd‐excited XRF spectrometer. Principal components analysis was used for spectral data compression and pattern recognition (including for those SQI spectral signatures without any visibly discernible characteristic X‐ray lines), whereas partial least squares regression and artificial neural networks were used to build a calibration and quantitative analysis strategy. The method furnishes soil micronutrient and macronutrient information simultaneously and rapidly (t = 200 s). To the best of the authors' knowledge, this is the first time that an XRF method has demonstrated spectroanalytical potential for quantitative macronutrients analysis in soils applicable to routine SQA. Coupling EDXRFS with multivariate chemometrics enables rapid and reliable assessment of chemical SQIs. Copyright © 2011 John Wiley & Sons, Ltd.     

Online Copper Removal for Selenium Determination by Hydride Generation–Inductively Coupled Plasma Optical Emission Spectrometry

Abstract

Selenium determination in samples with a high copper content by hydride generation–inductively coupled plasma optical emission spectrometry (HG‐ICP‐OES) after online copper removal and selenium (VI) reduction is described. An activated carbon minicolumn was used for the retention of copper and its subsequent separation of Se. Se(VI) was then online reduced by heating into a PTFE coiled reactor with 12 M HCl. The analyte was introduced into a water stream containing sodium tetrahydroborate (NaBH₄) in order to generate selenium hydride (H₂Se). The detection limit (DL) obtained was 0.8 µg L^?1, and the precision, expressed by the relative standard deviation (RSD), was 2.5% (n=10; 10 µg L^?1 selenium level). The current method was applied to the Se determination in two copper reference materials, MBH‐39DK 3601 (with a Se content of 90 mg kg^?1) and MBH‐39 DK 3604 (with a Se content of 15 mg kg^?1).     

Improvement of spatial resolution of µ‐XRF by using a thin metal filter

An improvement of spatial resolution of µ‐XRF by using a thin metal filter was investigated. The size of the x‐ray beam focused by the polycapillary x‐ray lens depended on the energy of the characteristic x‐rays. Original spot sizes at the focal point were 48 µm for CrKα, 41 µm for NiKα, and 28 µm for MoKα, respectively. To make the x‐ray beam size small, Ti? Cu thin foil was placed between the output of the lens and the focal point as a metal filter to reduce the continuous x‐rays. Finally, the x‐ray microbeam size was improved to 30 µm by applying a filter. Clear 2D mapping images of Cr, Fe, and Ni in 300‐mesh stainless steel could be obtained by applying this filter. Copyright © 2008 John Wiley & Sons, Ltd.     

Impaired pulmonary blood flow distribution in congestive heart failure assessed using synchrotron radiation microangiography

Synchrotron radiation microangiography is a powerful tool for assessing adverse changes in pulmonary vessel density associated with primary pulmonary hypertension (PH). Congestive heart failure (CHF) leads to a `secondary' onset of PH, yet it is unknown whether secondary PH is also associated with reduced vessel density. This study utilized synchrotron radiation to assess both pulmonary vessel density and endothelial function in a Dahl rat model of CHF with secondary PH. High salt‐fed Dahl salt‐sensitive (Dahl‐S) and salt‐resistant (Dahl‐R) rats were anesthetized and microangiography was performed to assess the pulmonary vessel density and vascular responses to (i) sodium nitroprusside (5.0 µg kg^?1 min^?1), (ii) acetylcholine (3.0 µg kg^?1 min^?1) and (iii) ET‐1_A receptor blockade, BQ‐123 (1 mg kg^?1). Dahl‐S rats developed CHF and secondary PH as evident by endothelial dysfunction, impaired vasodilatory responses to acetylcholine, enhanced vasodilatory responses to BQ‐123 and extensive pulmonary vascular remodeling. Consequently, the pulmonary vessel density was adversely reduced. Interestingly, the etiology of secondary PH manifests with structural and functional changes that are comparable with that previously reported for primary PH. One important discrepancy, however, is that ET‐1 modulation of pulmonary vessels is most striking in vessels with a diameter range of 100–200 µm in secondary PH, in contrast to a range of 200–300 µm in primary PH. Such discrepancies should be considered in future studies investigating primary and secondary forms of PH.     

Semiempirical approach for standardless calibration in µ‐XRF spectrometry using capillary lenses

Quantitative µ‐XRF analysis based on standardless calibration is limited by the lack of information on the shape of the excitation spectrum resulting from using capillary lenses. The measurement of radiation scattered from a sample was used in combination with Monte Carlo simulation of radiation transport to estimate the energy spectral distribution of the excitation radiation. Further, a standardless calibration based on the fundamental parameter method implemented in the IAEA‐QXAS software package was carried out and verified for glass and fused ore certified reference materials. The accuracy and repeatability achieved are reported. Copyright © 2004 John Wiley & Sons, Ltd.