Excited Energy Dispersive X-ray Fluorescence Research Articles

X-ray fluorescence analysis of cultural artefacts — Applications to the Czech heritage

X-ray florescence analysis is an excellent non-destructive tool for analysing the elemental composition of materials in a wide range of works of art. The Department of Dosimetry and Application of Ionising Radiation at CTU-FNSPE has used radionuclide or X-ray tube excited energy dispersive X-ray fluorescence for many kinds of artefacts, including frescos, paintings, manuscripts, metal sculptures and other objects, ceramics, jewellery, various archaeological finds, etc. The method used is more or less “traditional”, i.e., semiconductor spectrometry of excited X-rays, with some optional choices—capillary optics for collimation of exciting beams and two-dimensional scanning. The “hardware” complex is supplemented by techniques for estimating the depth distribution of measured elements, for suppressing surface effects, for in situ non-contact measurements, etc. Extending the measurable range to lighter elements and decreasing the detection limits is one of the achievements that has been attained by improving the instrumentation and techniques that are used. This paper gives a brief review of works carried out at the Department of Dosimetry and Application of Ionising Radiation at CTU-FNSPE.

Trace elemental analysis of mitral valves by EDXRF

The elemental analysis of mitral valves from 12 patients with rheumatic mitral valve disease was performed using radioisotope excited energy dispersive X-ray fluorescence (EDXRF) technique. An annular 50 mCi55Fe radioactive source was used for excitation of characteristic K X-rays of the trace elements in the samples. A high resolution Si(Li) detector, which has a 160 eV full width at half maximum for 5.9 keV photons, was used for intensity measurements. Concentrations of the elements P, S, K and Cl in the mitral valve samples were determined by using standard addition method. Deficiencies or excesses of these trace elements cause the valves to run irregularly. Abnormal value of these elements may also result in rheumatic valve disease.

Trace elemental analysis of mitral valves by EDXRF

The elemental analysis of mitral valves from 12 patients with rheumatic mitral valve disease was performed using radioisotope excited energy dispersive X-ray fluorescence (EDXRF) technique. An annular 50 mCi 55 Fe radioactive source was used for excitation of characteristic K X-rays of the trace elements in the samples. A high resolution Si(Li) detector, which has a 160 eV full width at half maximum for 5.9 keV photons, was used for intensity measurements. Concentrations of the elements P, S, K and Cl in the mitral valve samples were determined by using standard addition method. Deficiencies or excesses of these trace elements cause the valves to run irregularly. Abnormal value of these elements may also result in rheumatic valve disease.

Distribution of trace elements in the coastal sea sediments of Maslinica Bay, Croatia

Spatial distributions of trace elements in the coastal sea sediments and water of Maslinica Bay (Southern Adriatic), Croatia and possible changes in marine flora and foraminifera communities due to pollution were investigated. Macro, micro and trace elements’ distributions in five granulometric fractions were determined for each sediment sample. Bulk sediment samples were also subjected to leaching tests. Elemental concentrations in sediments, sediment extracts and seawater were measured by source excited energy dispersive X-ray fluorescence (EDXRF). Concentrations of the elements Cr, Cu, Zn, and Pb in bulk sediment samples taken in the Maslinica Bay were from 2.1 to over six times enriched when compared with the background level determined for coarse grained carbonate sediments. A low degree of trace elements leaching determined for bulk sediments pointed to strong bonding of trace elements to sediment mineral phases. The analyses of marine flora pointed to higher eutrophication, which disturbs the balance between communities and natural habitats.

Seasonal variations in the concentrations of selected heavy metals and radionuclides in Sava River sediments upstream and downstream of NPP Krsko

In order to estimate the influence of a nuclear power plant and other industrial and agricultural anthropogenic sources on the quality of Sava River sediments, samples taken from seven locations (one upstream and six downstream of the Krsko NPP) were characterized. Seasonal variations in the sediment composition were determined on the basis of four samplings taken during the year 2004 (in February, May, October and December). Total concentrations of the elements Cr, Mn, Fe, Cu, Zn, Co and Pb in the sediment fractions less than 0.5mm have been measured by source excited energy dispersive X-ray fluorescence (EDXRF), while 40K, 137Cs, 131I, 7Be, 228Th, Th(228Ra), U(234Th), 226Ra and 210Pb were determined by gamma spectrometry. Mineralogical examinations of the samples were performed using the X-ray diffraction (XRD) method.

Determination of lanthanides by source excited energy dispersive X-ray fluorescence (EDXRF) method after preconcentration with ammonium pyrrolidine dithiocarbamate (APDC)

A new analytical procedure for determination of lanthanides in environmental samples after chemical separation from major matrix elements on DOWEX 50W-X8 resin followed by preconcentration with chelating agent ammonium pyrrolidine dithiocarbamate (APDC) and analyses of thin targets by energy dispersive X-ray fluorescence (EDXRF) method using 109Cd as the source of excitation was presented. Characteristic Lα X-ray lines of the lanthanides were used for calculations of the net peak area and mass concentrations. The influence of pH value of the solution and addition of organic matter on the complexation was investigated. Percentage of recovery of each lanthanide after separation on DOWEX 50W-X8 resin was also determined. Accuracy of the method was tested on standard reference materials and real environmental samples (red mud material). For that purpose samples of standard reference materials and red mud were prepared as thick targets and directly analyzed (without the separation step) by EDXRF method using 241Am as the excitation source. In that case lanthanides concentrations were determined over their characteristic Kα X-ray lines and results were compared with those obtained after separation/preconcentration step described above. Results showed that selected lanthanides made stable complexes with APDC in the alkaline medium with the maximum recovery at pH = 8. The presence of organic matter slightly modified the complexation by means of somewhat higher recovery percentage at pH lower than 7 and approx. 20% lower recovery at pH higher than 7. Recovery of the elements after separation on DOWEX 50W-X8 resin and preconcentration with APDC at pH = 8 varied from 91.4% (Pr) to only 24.9% in the case of Dy. Concentrations of lanthanides measured in standard reference material and environmental samples of red mud after microwave digestion, separation on DOWEX 50W-X8 resin, preconcentration with APDC at pH = 8 and recalculation on the percentage of recovery were in good agreement with certified values in the case of SRM as well as with the concentrations obtained by direct determination over Kα lines using 241Am excitation source in the case of red mud leading to the conclusion that presented method was applicable for the determination of lanthanides in real environmental samples.

Biomonitoring of heavy metals and arsenic on the east coast of the Middle Adriatic Sea using Mytilus galloprovincialis

Results of two years monitoring of heavy metals and arsenic concentrations in soft tissue of Mediterranean blue mussel Mytilus galloprovincialis are presented. Samples were taken at six localities (five exposed to various pollution sources and one control site) on the east coast of the Middle Adriatic in October 2003 and 2004 and in April 2004 and 2005. All measurements were carried out with source excited Energy Dispersive X-ray Fluorescence Method (EDXRF). Measured concentrations were in the following ranges: Pb (2–7 mg/kg); As (4–30 mg/kg); Cr (1–2.9 mg/kg); Mn (2–13 mg/kg); Fe (53.4–719 mg/kg); Ni (0.8–5 mg/kg); Cu (3.7–11.1 mg/kg) and Zn (59.1–273 mg/kg). Maximum values of the most elements were measured in samples from the most polluted Vranjic region. Statistically significant difference among six localities ( p = 0.05) was found for As, Fe and Zn while Mn, Fe and Cu showed significantly higher concentrations in spring period. None of the selected elements showed significant difference between the control and exposed regions.

Heavy Metals in Soil, Grape, and Wine

The elemental concentrations of nine elements (V, Cr, Mn, Fe, Ni, Cu, Zn, As and Pb) were determined in soil, grape and wine samples taken from the wine producing area of Vrbnik on the island Krk in the northern Adriatic) using the tube excited energy dispersive X-ray fluorescence, EDXRF method. Extensive grape cultivation in Vrbnicko polje through the years approximately doubled the Cu content in the soil from this area compared to the background level determined on Krk. Most of this total Cu is exchangeable and thus available to plants. The concentrations of all other elements are similar to those found in the Krk soil. Canonical analysis showed that the main source of heavy metals in grape was absorption from the soil. Statistically significant differences in elemental composition between red and white wine were found. All elements showed greater concentrations in red grape. In spite of the elevated Cu level in the soil, the content of this metal in wine was much lower than the allowed value.

Energy dispersive X-ray fluorescence and neutron activation analysis of surficial sediments of the Sea of Marmara and the Black Sea around Istanbul

Surficial sediment samples, collected from 27 sampling sites of the Sea of Marmara and the Black Sea nearby Istanbul area in 1996 and 1999 years, were analyzed quantitatively for some heavy metals and some other elements by using radioisotope excited energy dispersive X-ray fluorescence (EDXRF). The U and Th concentrations of the samples were determined by instrumental neutron activation (INAA). The results were compared with those from other contaminated and uncontaminated sedimentary materials. It is found that some elemental concentrations of the Sea of Marmara and the Black Sea sediments are comparable with those in most other sea sediments in the vicinity of densely populated regions.

Determination of the alloying elements in ancient silver coins

Isotope excited energy dispersive X-ray fluorescence (EDXRF) was used for the determination of the major components, silver and copper, of ancient coins. A ring shaped 125I source was used for excitation. Various methods were developed and compared for quantitative evaluation in order to eliminate matrix effects and the effects caused by the differences in geometry. The method proposed by the authors ensures determination with acceptable error using certified standard samples of alloys. The results of this method were compared with those of prompt gamma activation analysis (PGAA) and with data from contemporary written sources.

Analysis of stainless steel samples by energy dispersive X-ray fluorescence (EDXRF) spectrometry

A simple method for the analysis of stainless steel samples is presented which is based on radioisotope excited energy dispersive X-ray fluorescence (EDXRF) spectrometry and does not require any type-standards. Both absorption and enhancement effects have been taken into account in the fundamental parameter method for quantitative analysis and an iterative approach is followed for calculation of concentrations in steel samples. Non-linear least square fitting (NL-LSF) procedures have been used to determine accurately the fluorescent peak intensities. The method has been tested by analysing several CRM standard reference samples and 304 and 316 steel samples assuming as unknown. The EDXRF results have also been compared with the results of analysis of same samples by vacuum emission spark spectrometry (VES). Obtained values for concentration in steel samples match quite well with their certified values.

Radioisotope excited EDXRF analysis of sediment core samples from the southern part of the Black Sea

In all 43 sediment samples were collected as gravity cores in depthfrom 70 to 150 cm, from the 20 sampling sites of the continental slope ofthe southern part of the Black Sea, during 1978. The samples were quantitativelyanalyzed by radioisotope excited energy dispersive X-ray fluorescence spectrometry(EDXRF) using fundamental parameter technique (FTP). The investigated sedimentsamples were the organic rich-mud components of the core samples, which wereknown as rich in metals. The metal concentration ranges were as follows: Ca(3.1–12.9%), Ti (1000–2000 µg/g), V (40–150 µg/g),Cr (30–200 µg/g), Mn (200–1500 µg/g), Ni (25–100µg/g), Cu (20–70 µg/g), Zn (20–50 µg/g), Br(15–670 µg/g), Rb (5–90 µg/g), Sr (80–700 µg/g),Y (10–20 µg/g), Mo (10–111 µg/g), Zr (20–190µg/g), Cd ( <1–5 µg/g), Sb ( <1–5 µg/g),I (10–430 µg/g), Ba (100–1650 µg/g), La (5–18µg/g), Ce (12–38 µg/g) and Nd (6–17 µg/g). Thesediment cores systematically collected in 1978 by Mineral Research and ExplorationInstitute of Turkey (MTA) are the oldest available sediment samples from theTurkish coastline of the Black Sea. Therefore, the results may be used asreferences for monitoring possible future metal pollution.

Optimization of X-ray fluorescence elemental analysis: an example from Kenya

A systematic study and application of a radioisotope excited energy dispersive X-ray fluorescence analysis method to multi-elemental determination in Kenyan rock samples whose supporting matrices are of light elements is presented. The method consists of instrumentation and analytical parameter optimization, and an empirical background stripping model for reduced dark matrix scatter effects. The method was applied to trace, minor and major elemental determination in rock samples collected from various parts of Kenya in order to test it for routine mineral and geochemical prospecting in light element geological matrices. A correlative analysis of the samples revealed a common presence of elements: K, Ca, Ti, Cr, Mn, Fe, Cu, Zn, Ga, Au, Pb, Br, Rb, Sr, Nb, Zr, As and Y in all five types of rocks, down to 3.0 μg g −1 for Br, with major differences revealed in the rock tectonic setting, origin, age and related palaeomagnetic parameters, and mineral enrichment prospects.

Window Area Effects in the Detector Efficiency for Source Excited EDXRF Geometries

AbstractThe efficiency dependence on detector window area for three different geometries of source excited energy dispersive X-ray fluorescence (EDXRF) analysis systems are calculated using the Monte Carlo method. Two typical samples (coal and oil) are considered for discussion. The results show that the efficiency is affected mainly by geometric factors: source-to-sample distance and absorption of the exciting X-rays; fluorescent photon self-absorption has a much smaller effect.

The application of XRF analysis in the determination of113mCd

The overall recovery of the separated113mCd with added Cd carrier from 50 l samples of natural water was determined by a secondarysource tube excited energy dispersive X-ray fluorescence spectrometer measuring the amount of cadmium in the final CdS+CuS coprecipitate on a 25 mm diameter Millipore filter. The method enables to determine 1–20 μg Cd in 100 sec. with a limit of detection of 0.8 μg.

Synchrotron radiation excited X-ray fluorescence analysis using wide band pass monochromators

Wide band pass X-ray monochromators using reflection/transmission mirror and reflection mirror/absorber combinations were applied to the synchrotron radiation excited energy dispersive X-ray fluorescence analysis. Transmission mirrors were made from soap films or thin mylar films and were used as high pass filters. Characteristics of both films are described in detail. The width of band pass thus obtained was wider than 20%. Minimum detection limits in relative concentration and absolute amount are of the order of 0.1 ppm and less than 0.1 pg, respectively, when there is no line interference.

The Recessed Source Geometry for Source Excited X-Ray Fluorescence Analysis

AbstractDifferent geometries are considered for source excited energy-dispersive X-ray fluorescence (EDXRF) analysis Systems, including the recessed source geometry introduced in the present work. The calculated physical excitation-detection efficiencies, for the side (or annular), central, receded and recessed source geometries are presented as a function of the target to source distance, for Ca, K, S and Si targets excited with a Fe-55 XBF-3 X-ray source and xenon filled gas proportional scintillation counters. The last two geometries present in gênerai the highest efficiencies. The recessed source geometry présent the best performance with peak efficiencies a factor of 3.3 better than those for the standard side or annular source geometries.

Trace elemental analysis of extracted dust from lungs and lymph nodes of domestic animals using X-ray fluorescence technique.

Samples of dust extracted from the lungs and lymph nodes of certain domestic animals from West Bengal, Orissa, Bihar provinces of India were quantitatively analysed using photon excited energy dispersive X-ray fluorescence technique. Thin specimens were prepared for analysis to minimize matrix enhancement and absorption effects. Amongst the various elements analysed, Hg, Fe, Cu, Zn and Pb were found to be present in appreciable amounts. An important finding was the presence of a very high concentration of Hg in extracted dust samples from West Bengal. The significance of the various results obtained in this investigation is discussed.

Application of radioisotope excited energy dispersive X-ray fluorescence determination of palladium in catalysts and doped venezuelan laterites

A rapid procedure for determining palladium in catalysts and geoiogical materials is presented. This method involves the use of an241Am (100 mC) source for excitation and employs a PDP-11/05 processor for the data acquisition and analysis by energy-dispersive X-ray fluorescence. The relative standard deviation for 5 independent determinations is less than 3% for 100 seconds of fluorescent time. The calculated and measured values agreed well for both, the prepared standards and the doped Venezuelan laterites. Finally, data on the different sources of error is given including counting time, sample preparation, and total error.

Determination of Sulfur, Ash, and trace Element Content of Coal, Coke, and Fly Using Multielement Tube-Excied X-ray Fluorescence Analsis

A procedure using tube excited energy dispersive x-ray fluorescence analysis with interelement corrections has been developed for multielement analysis of major and trace elements and ash content of coal, coke, and fly ash. The procedure uses pressed pellets and an exponential correction for interelement effects. The average deviations ranged from about 0.0003% for V at an average concentration of about .003% to 0.1% for S at an average concentration of 4%. About 25 elements were measured and 100 second minimum detectable concentrations ranged from about one part per million for elements near arsenic to about one tenth of one percent for sodium.