Energy Dispersive X-ray Fluorescence Measurements Research Articles

One-step hot-press synthesis of amino functionalized Zr-based metal organic framework for determination and speciation of trace inorganic arsenic species in water samples with EDXRF spectrometry

Herein, amino functionalized Zr-based metal organic framework (UiO-66-NH2) on carbon cloth substrate was synthesized by using one-step hot-pressing method and the product (UiO-NH2@CC) was evaluated as a new solid phase extraction (SPE) material for determination and speciation of inorganic arsenic species (As(V) and As(III)) in water samples through energy dispersive X-ray fluorescence (EDXRF) spectrometry. SPE efficiency of UiO-NH2@CC was examined in batch and continuous adsorption (pre-concentration) processes and combination of either batch or continuous pre-concentration process with EDXRF spectrometry proposed analytical method, offering remarkable benefits (i.e., user-friendly, no elution procedure, environmentally friendly and cost-effective, etc.). Batch adsorption studies indicated that As(V) could be selectively adsorbed by UiO-NH2@CC at pH 2 and better represented by Freundlich isotherm model in 60 min of equilibrium time. Continuous adsorption studies at pH 2 demonstrated a drop in As(V) adsorption efficiency of UiO-NH2@CC for sample loading volume above 30 mL with increasing flow rate from 0.3 to 1.0 mL/min and initial As(V) concentration from 20 to 100 µg/L. By considering fortification experiments on real water samples at two levels (5 and 50 µg/L) of As(V) species, both batch and continuous pre-concentration steps coupled with EDXRF spectrometry, with LOD values of 0.790 and 0.220 µg/L, respectively, indicated good recoveries in the range of 87(±11)–104(±7) with no statistically significant differences. Finally, the continuous pre-concentration step followed by EDXRF measurement, as a representative analytical method, was of successful applicability to the speciation of As(III) and As(V) in real water samples with notable advantages (i.e., effortless, economical, practical and reproducible, etc.).

Elemental geochemistry insights into source inputs, paleo-productivity, and paleo-depositional conditions of the Montney Formation

The analysis of the elemental composition of sediments provides valuable information about input sources, paleoredox conditions, or paleoproductivity. In this study, 1498 rock samples from six wells within the Triassic Montney Formation in Central Alberta, Western Canada, were analyzed using energy-dispersive X-ray fluorescence (ED-XRF). Wavelength dispersive X-ray fluorescence measurements were used to build and validate a Montney-specific calibration to interpret elemental concentrations from the ED-XRF dataset. The calibration accounted for heterogeneities, matrix variations and unique elemental associations that may be present within the Montney Formation. Sediment input sources are interpreted based on cross-plots of proxy elements to be terrigenous, carbonates and biogenic in origins. Analysis of multiple paleoredox proxies indicated the environment of deposition to be mainly oxic. The ratios of potassium (K) to rubidium (Rb) were used as a paleoclimate proxy. Results suggest the predominance of low chemical weathering attributed to a hot and arid paleoclimate during deposition of Montney Formation sediments. Phosphorous concentrations were determined to be strongly associated with Ca, as such it was interpreted to be inorganically sourced, thereby precluding it from being used to assess paleoproductivity. Excess Si interpreted to be biogenically sourced was used in interpreting moderate and high paleoproductivity for the Montney formation. This work demonstrates the versality of matrix-specific calibrated ED-XRF measurements as a valuable, cost efficient, standalone technique in geochemical analysis for characterizing geological formations.

Investigation of the X‐ray fluorescence technique in the characterization of Ni coatings applied to historical heritage studies

AbstractHistorical heritage pieces allow a better comprehension of the characteristics of different civilizations over time. The characterization of such pieces is of paramount importance for their preservation. Energy‐dispersive X‐ray fluorescence (EDXRF) is recommended for this application, mostly because it is non‐destructive and the equipment is portable. However, one of its limitations is the difficulty in separating the signal from the substrate and the coating of multilayered samples, as it does not provide depth resolution. This project investigates the application of EDXRF in the characterization of metallic coatings, in the context of historical heritage. The elemental concentration of electrodeposited Ni coatings onto carbon steel substrates was obtained from EDXRF analyses. The relationship between the layer thickness and the variation of the Kα/Kβ intensity ratio of nickel peaks was exploited and the thicknesses of the coatings were estimated through EDXRF measurements. For comparison, particle‐induced x‐ray emission spectroscopy and scanning electron microscopy of the cross‐section were employed, providing a depth profile of the coatings. The estimated thicknesses from EDXRF analysis were comparable to those observed in the microscopy images for thinner films (up to 8 μm). On the other hand, for thicker films, the thicknesses were underestimated, due to the technique's depth limit and matrix effects, as secondary absorption. Despite these limitations, EDXRF remains valuable for evaluating cultural heritage pieces, often providing sufficient information to address authenticity concerns or to guide restoration processes. A case study was also performed to apply the methodology discussed on historical metallic pieces.

The K-X-ray intensity ratios as a tool of examination and thickness measurements of coating layers

The ED-XRF (Energy-Dispersive X-ray Fluorescence) measurements and the FLUKA simulations have been made to discuss the possibility of recognition of coating layer as well as to its thickness measurement. In this work the IKα(Cu)/IKα(Ag) intensity ratios as well as IKβ(Ag)/IKα(Ag) and IKβ(Cu)/IKα(Cu) for copper samples coated with various thickness of sputtered silver have been analyzed. The results show strong dependence of these factors with coating silver layer thickness.The measurements show the performance of this method in archaeometry. Since the use of non-destructive methods during tests on ancient silver artifacts may not supply to obtain reliable bulk results and should be considered applicable for only surface analyses, the measured intensity ratios can be applied as a tool to estimation of surface silver enrichment thickness.

Towards in-situ fumes composition monitoring during an additive manufacturing process using energy dispersive X-ray fluorescence spectrometry

We present an in-situ energy dispersive X-ray fluorescence measurement of the content of Chromium and Nickel in the fumes produced by selective laser melting on an Inconel 625 powder. Significant variations of the intensities of the Chromium and Nickel Kα fluorescence lines were evidenced as a function of the laser power, lasing velocity and chamber atmosphere. Calibration has been carried out using Monte–Carlo particle transport simulations allowed to obtain a quantitative estimate of the Chromium and Nickel mass fraction in the fumes. The experimental data has been compared to the predictions of an analytical physico-chemical model with consistent results. This approach thus also allows to provide information on the temperature of the metallic bath.

Improving the accuracy of EDXRF results in gold alloy analysis by matrix effect correction

Energy-Dispersive X-Ray Fluorescence (EDXRF) is a faster non-destructive analysis and demands less sample preparation than the fire assay technique. This research sought to minimise the matrix effect (inter-element) by studying the role of matrix-specific materials and thus improving the accuracy of EDXRF in gold alloy analysis. The combination of empirical calibration with standardless Fundamental Parameter (FP) was expected to fine-tune the analysis of precious metals, such as gold (Au), silver (Ag), and copper (Cu). The acquired R2 of 0.9999 for all metals signalled an alignment between the certified value and EDXRF measurement. The technique was validated with CRMs to determine corrective K-factors to realign systematic measurement errors due to alloy mixture. The relative error (rel%) for all measurements was <0.1 rel%. The relative standard deviation (%rsd) was reduced to <0.11%rsd for pure Au, 0.16%rsd for Au-Ag and Au-Cu mixture, and <0.20%rsd for Au-Ag-Cu mixture with K-factor correction. A similarity to the fire assay might reduce bias. The null hypothesis of equal mean values of fire assay and XRF data was confirmed by the student's t-test. This outcome showed that the XRF provided acceptable precision and verified the null hypothesis on the equivalence between mean results.

Application of the US EPA procedure for determining method detection limits to EDXRF measurement of filter-based aerosol samples

ABSTRACT The US Environmental Protection Agency (USEPA) modified its guidance on determining “method detection limits” (MDL) in 2017. The recommended procedures have not yet been applied to the analyses routinely done on filter samples for USEPA’s Chemical Speciation Network (CSN). This paper applies the new USEPA procedure for estimating MDL to Energy Dispersive X-Ray Fluorescence (EDXRF) analysis of atmospheric aerosol samples collected on filters. The procedure involves estimating MDL by two approaches – statistical distributions of unloaded blank sample measurements and lightly loaded, spiked samples – and sets the MDL as the maximum of these two approaches. Spiked samples at low concentrations were developed using an aerosol deposition chamber to follow this approach. The MDL procedure was initially conducted on one EDXRF instrument, and the spike-based MDL was found to be higher than blank-based MDL for 28 of the 31 elements. The blank-based MDL was higher than the spike-based MDL for Si, K and Fe, which are common contaminants present in filter raw media or arising from EDXRF hardware. The annual verification performed using five EDXRF analyzers demonstrated that the MDL estimated following the USEPA procedure was stable over time and analyzers for all elements except K, which yielded a higher MDL. Implications: Lightly loaded reference materials (RM) were developed for Energy Dispersive X-ray Fluorescence (EDXRF) measurements of elemental concentrations in filter-based particulate matter samples using a novel aerosol generation chamber. These RM were then used to estimate method detection limits (MDL) following U.S. Environmental Protection Agency guidance. These new MDL estimates were compared to alternative estimates and, for most elements, are higher. Our work provides EDXRF users with MDL estimates for each element and an assessment of different MDL estimation approaches.

Investigation Techniques of Arson Fire in Low-Temperature Warehouses Using ED-XRF

Investigation techniques for fire prevention in low-temperature warehouses were studied using energy dispersive X-ray fluorescence (ED-XRF). In the first experiment, a sample (galvanized steel sheet plus urethane foam plus sandwich panel) was burned with 500 mL of a flammable liquid (gasoline, thinner, kerosene, and light oil)/ Then, the component change of the sample was measured. In the combustion experiment, there was a difference in the heat of combustion depending on the type of flammable liquid; however, as a result of measuring the component change of the sample with ED-XRF after combustion, the largest component change was measured in the combustion experiment with gasoline. The change was in the order of thinner, kerosene, and diesel. Using ED-XRF, it was possible to distinguish the flammable liquid used in the experiment by measuring the component change of the sample resulting from the difference in the combustion heat of the flammable liquid. A second experiment was conducted under the same conditions as the first experiment, assuming a fire brigade fire suppression condition, and the combustion time of the flammable liquid was limited to 600 s. A combustion characteristic of flammable liquids is that the temperature and heat flux reach the maximum value within 300 s after the start of combustion regardless of the type of liquid. Because the change of composition was confirmed in the order of light oil, it was possible to distinguish the flammable liquid used at the fire site using the ED-XRF measurement result.

Influence of soil sample grain size on energy dispersive X-ray fluorescence analysis: a comparative study case with three spectrometers

This study aims at evaluating the particle size influence on the quantitative Energy Dispersive X-ray Fluorescence data of tropical soils, as well as evaluating the results trueness and precision using different statistical approaches. These objectives were conducted in three spectrometers, a benchtop one, and two portable ones. Certified reference materials were employed in calibration and trueness evaluation. Soil samples were collected, grounded and sieved in particle sizes: macerated (>2 mm), <2, <0.7, <0.3, <0.125, and <0.06 mm. The three spectrometers had different performances and lack of trueness for Potassium and Zinc in the Lab-made spectrometer. Regarding the grain size parameters, the spectrometers responded in different ways. It was identified that the best soil grain size condition for one of the portable spectrometers was <0.06 mm, while for the benchtop and for the other portable spectrometer the best soil grain size was <0.125 mm. In summary, the soil grain size affected the quantitative results in Energy Dispersive X-ray Fluorescence measurements, but it depends on the sensitivity of each spectrometer and the element of interest.

A Direct Non-destructive Method for Determination of Sulfur in Ore Samples Using EDXRF Spectrometry.

A method has been developed for direct non-destructive energy dispersive X-ray fluorescence (EDXRF) determination of sulfur in solid uranium ores and intermediates, obtained from the alkaline recovery process for uranium from its ores. The method involves thorough grinding of a few mg of solid powder samples to fine particle size and mixing the fine powder thus obtained with a few drops of 10% collodion solution in amyl acetate to make a paste. A very small amount of this paste was transferred with the help of the pestle tip, spread uniformly in the form of thin slurry on Mylar films, and dried to make very thin sample specimens on thin Mylar film supports. These specimens were presented for EDXRF measurements. A calibration plot was made by plotting the intensity ratios of S Kα and Rayliegh scattered peak of the excitation source (Ge Kα) against sulphur percent in the certified reference materials (CRMs). It was found that the precision obtained using this methodology was within 5% (±1σ) and the deviation of the EDXRF analytical results from the expected values of CRM was within 7%. The developed method was successfully applied for the determination of sulfur in the samples obtained from the different stages of the uranium ore processing using alkaline based leaching method.

Semi-empirical determination of Kα1,2, Kβ1,3, and Kβ2,4 X-ray natural line widths for various elements between 29 ≤ Z ≤ 74 at 123.6 keV

In this study, Kα1,2, Kβ1,3, and Kβ2,4 X-ray natural line widths for various elements were determined semi-empirically at 123.6 keV by using K shell fluorescence yields obtained from energy dispersive X-ray fluorescence measurements. The obtained results contribute to a database for the development of new theoretical models of atomic structure, radiation shielding materials, and designing new technological devices related to the structural analysis of materials. The obtained results were compared with the literature, while new fitting polynomials for the studied parameters were acquired. The results showed that the natural linewidths of K X-ray lines fit fourth-order polynomials except for Kβ2,4.

Implementation of a portable EDXRF measurement chain for characterization of metallic objects of cultural interest in Colombia

The study of cultural heritage requires sophisticated equipment that does not alter or destroys the materials composing the objects under study. The main requirement about an artifact or an ancient work of art, for its restoration or conservation processes, is information about its constituting elements. Energy-dispersive X-ray fluorescence (EDXRF) is a very versatile and relatively inexpensive technique for conducting a nondestructive elemental analysis. In this paper, we present the design and implementation of a hand-hold X-ray fluorescence spectrometer. Although the EDXRF measurement chain appears to be a simple technique to assemble and use, it requires extensive knowledge about the proper handling of the X-ray beam, the analysis of the spectrum and whether the obtained spectrum is appropriate for a qualitative and quantitative analysis. Even geometry is one of the most important factors since the source-sample-detector distances must be handled with meticulousness to obtain optimal spectra. Acquisition time and the amount of accumulated counts to obtain high resolution spectral peaks are very important as well.This work shows the results obtained from metallic samples of Colombian cultural interest belonging to the collection of Museo Universitario Universidad de Antioquia.

Trace element determinations in uranium by energy dispersive X-ray fluorescence spectrometry using thin film specimens

Thin film specimens on scotch tape base with analyte amounts in ng level have been used for trace element determinations in Certified Reference Materials (CRMs) of uranium oxides. The samples were prepared by dissolving the CRMs in nitric acid and separating the major matrix uranium by solvent extraction. Small volume aliquots of the aqueous phases, obtained after uranium matrix separation from sample solutions, were mixed with gallium internal standard and deposited on scotch tape supports. These specimens were presented for Energy Dispersive X-Ray Fluorescence measurements. The trace elements present in the specimens were determined after processing the spectra and consideration of the relative sensitivity values of the elemental X-ray lines. The results obtained were found to be in good agreement with the Total reflection X-Ray Fluorescence (TXRF) determined and certified values. The methodology has all the advantageous features of TXRF for nuclear material elemental characterization e.g. small sample amount requirement, multi-elemental analytical capability etc. along with simple instrumentation. In addition, such specimens can be isolated using scotch tape sealing and spread of radioactive materials during their analysis can be avoided.

Characterization of building materials by means of spectral remote sensing: The example of Carcassonne's defensive wall (Aude, France)

Geological and archaeological analysis of stone masonries in standing structures helps reveal information about use of natural resources. At the same time, the study of historical materials is useful for conservators and cultural heritage management. Geochemical and petrographic analysis of building material types is usually done through destructive analysis on a few selected samples and can be problematic due to the costs of operations and the size of buildings themselves. This paper demonstrates that the combination of hyperspectral imaging portable Near Infrared (NIR) spectroscopy and Energy Dispersive X-ray Fluorescence (ED-XRF) spectroscopy can be useful for analysing types of raw materials used in distinct construction phases of the inner defensive wall in the citadel of Carcassonne (Aude, France). Stratigraphic analysis of the architecture, short-range spectral remote sensing and portable ED-XRF measurements were combined in an interdisciplinary approach to classify sandstone elements. The experimental protocol for in situ non-destructive analysis and classification of the masonry types allows the investigation of the monument in a diachronic perspective, collecting information to delineate raw materials varieties and their use or re-use through time.

Profiling of inorganic elements in coal seams using laboratory-based core scanning X-ray fluorescence techniques

The major inorganic elements in cores of coal and interbedded non-coal materials, ranging from 0.9 to 1.7 m in length, have been evaluated using energy-dispersive X-ray fluorescence (ED-XRF) measurement at close-spaced (2 mm) intervals in a laboratory-based Itrax core scanner, to evaluate the potential of this type of technology for use in quality assessment of potentially mineable coal seams in exploration and mine geology programs. The ED-XRF measurements from the scanner were calibrated against a suite of independently-analysed coals to provide quantitative data on the percentages of Si, Al, K, Ca, Fe, Ti and S at each individual point. With the exception of (total) S, also used in quality assessment, these values were recalculated as percentages of the relevant oxides, and combined to provide an estimate of the expected ash yield. Profiles were prepared illustrating the variation in the different components through the seam section, plotted alongside optical and X-radiograph images of the scanned core. Samples of selected intervals were analysed by conventional techniques and the ash yield, total sulphur and individual oxide percentages compared to those indicated for the same intervals by the core scan data. Despite difficulties due to precipitated salts and anomalous element concentrations on or near some core surfaces, as well as differences in moisture content between the scanned core and the conventionally-analysed samples, the results of this cross-checking have shown a general level of agreement for the different coal and non-coal materials involved. While the precision is not as high as that from conventional methods, the scan data allow the materials in the cores, including composites representing potentially mineable intervals, to be categorised to an extent that is of significant value for many exploration and mine geology applications.

Analytical Energy Dispersive X-Ray Fluorescence Measurements with a Scanty Amounts of Plant and Soil Materials

Elemental evaluations in scanty powdered material have been made using energy dispersive X-ray fluorescence (EDXRF) measurements, for which formulations along with specific procedure for sample target preparation have been developed. Fractional amount evaluation involves an itinerary of steps; (i) collection of elemental characteristic X-ray counts in EDXRF spectra recorded with different weights of material, (ii) search for linearity between X-ray counts and material weights, (iii) calculation of elemental fractions from the linear fit, and (iv) again linear fitting of calculated fractions with sample weights and its extrapolation to zero weight. Thus, elemental fractions at zero weight are free from material self absorption effects for incident and emitted photons. The analytical procedure after its verification with known synthetic samples of macro-nutrients, potassium and calcium, was used for wheat plant/ soil samples obtained from a pot experiment.

Radiochemical separation of 231Pa from siliceous cake prior to its determination by gamma ray spectrometry

Abstract A simple and fast radiochemical method for the separation of protactinium (231Pa) from siliceous cake for its determination by gamma ray spectrometry is described. The method involves (a) a novel approach, the fusion of the siliceous cake with sodium peroxide, (b) the dissolution of the fused mass in nitric acid and (c) the co-precipitation of 231Pa with manganese dioxide formed in-situ by the addition of solid manganous sulfate and potassium permanganate to the solution. The fusion, effected in a single step, is simpler and highly effective in comparison to methods reported hitherto in literature. The radiochemical yield of 231Pa, determined using 311.9 keV gamma ray of 233Pa radiotracer is quantitative (~90%). The decontamination factors calculated using gamma ray spectrometry and energy dispersive X-ray fluorescence measurements show that the separation from the interfering radionuclides is high whereas separation from major and minor elements is good. Separation by ion-exchange method in hydrochloric acid, hydrofluoric acid and oxalic acid media have comparatively much lower yields. The concentration of 231Pa in the siliceous cake measured using interference-free 283.6 keV gamma ray was found to be (6.4±0.33) μg kg−1. The measured concentration of 231Pa was well above the limit of quantitation whereas the coefficient of variation was ~5%. The improvement in the limit of detection was due to the reduction in spectral background. Systematic evaluation of various uncertainty parameters showed that the major contributors to the combined uncertainty were efficiency of the high purity germanium detector and the counting statistics. The present sample decomposition and separation methods are robust, simple to perform and can be effectively used for the determination and hence source prospecting of protactinium.

Development of a microanalytical energy dispersive X-ray fluorescence method for compositional characterization of (U, Pu)O2 samples

Elemental compositional characterization of (U, Pu)O2 samples is an important aspect for quality control of nuclear fuels. A microanalytical Energy Dispersive X-ray Fluorescence (EDXRF) method has been developed for the determination of plutonium and uranium. The method involves sample dissolution, addition of internal standard(s) into the sample solution, taking about 50μg of the sample on absorbent sheets, drying and sealing the specimens in such a manner that no loose radioactive particle comes out, during the analysis. Such approach does not require putting the instrument inside the glove box. These specimens were presented for the EDXRF measurements using Rh Kα as the excitation source. The amount of uranium and plutonium in samples were calculated using two different internal standards Ga and Y. The Pu weight percent (wt%) was calculated with respect to (U+Pu) in the samples. The results obtained were in good agreement with the biamperometric analysis results of the samples. The average precision observed was within 1% (1σ, n=4) and the deviation of the EDXRF determined values from expected values was within 2%. The detection limits obtained for Pu and U were 4μg.

Nutrients' K X-ray peak energy shift measurements in fenugreek plants and different soils treated with fertilisers

Energy dispersive X-ray Fluorescence measurements on plants and soils from a pot experiment on fenugreek with different soils; garden/sewage/factory and a specific peak analysis have been used to study cumulative effect of soil conditions/nutrient fertilisers on potassium/calcium/iron nutrients. Experimental set up comprises low power X-ray tube as photon source and Si (PIN) detector with energy resolution 145eV at 5.959 keV Mn K X-rays as X-ray detector. K peak energies of potassium/calcium/iron in plants and soils were precisely evaluated with SOLVER program of precision up to 10−4 of channel width. Potassium/calcium fertilisations produced large variations in peak energies in garden and sewage soils as compared to that in factory soil. Iron contents beyond its permissible limits in sewage and factory soils were found to suppress the nutrients uptake of plants with potassium/calcium fertilisers as compare to that in garden soil plants.

Eustatic controls on stratigraphy, chemostratigraphy, and water mass evolution preserved in a Lower Permian mudrock succession, Delaware Basin, west Texas, USA

Bone Spring (Leonardian) mudrock successions in Delaware Basin vary between silica- and carbonate-rich facies marking depositional responses to sea-level changes. Increased Mo, [Formula: see text], and total organic carbon (TOC) record reduced oxygenation during sea-level lowstands. In a 91.4-m (300 ft) core from Sun No. 1 Houssels well and a 39.6-m (130 ft) core from Shell No. 1 Marsden well (Reeves Co., Texas), lower Bone Spring cycles comprised siliceous-calcareous mudrock couplets. The Marsden core was correlative to the upper part of the Houssels core. Cyclicity was interpreted from mineralogical calculations at numerous core horizons using energy-dispersive X-ray fluorescence (ED-XRF) measurements of elemental content. Elemental abundances enabled predicting mineralogy based on the stoichiometric relationships between elements and dominant minerals (calcite and quartz), and from average values of Si and K in published illite analyses. The average sample spacing for ED-XRF measurements was 0.24 m (0.8 ft) for the Houssels core and 0.15 m (0.5 ft) for the Marsden core. The measurements and interpretations provided: (1) information regarding comparisons in stratigraphic and geographic development of facies over the 10-km (6.2-mi) distance between wells and (2) guidance for petrographic, scanning electron micrograph, and organic matter analyses that address processes that produced different facies. Greater carbonate abundance in the Houssels core reflected the proximity to carbonate shelves on the Central Basin Platform (CBP); the greater siliciclastic abundance in the Marsden core was thought to reflect the greater distance from the CBP. Redox element (S and Mo) and TOC concentrations were greater, and [Formula: see text] values were higher in some siliciclastic-dominated intervals, suggesting that anoxia characterized sea-level lowstands when normal marine water flowing from the Panthalassa Ocean was inhibited through narrow interbasin channels or over sills. Carbon isotope ([Formula: see text]) variations suggested changes in organic matter characteristics, whereby greater [Formula: see text]-depleted organic matter was deposited during sea-level lowstands, marking: (1) reduction of shallow-marine sources or (2) increased terrigenous organic carbon contributions.