Energy Dispersive X-ray Fluorescence Studies Research Articles

Bimetallic Ag-Cu Alloy Microflowers as SERS Substrates with Single-Molecule Detection Limit.

Bimetallic Ag-Cu alloy microflowers with tunable surface compositions were fabricated as surface-enhanced Raman spectroscopy (SERS) substrates with a limit of detection in the zeptomolar range for the analyte molecule rhodamine 6G (R6G). The substrates were prepared on a glass coverslip through a bottom-up strategy by simple thermolysis of metal-alkyl ammonium halide precursors. The reaction temperature and composition of the alloy were varied sequentially to find out the maximum SERS efficiency from the substrates. While UV-vis spectroscopy was employed to characterize the optical properties of the substrates, the bulk and surface compositions of the microflowers were determined using energy-dispersive X-ray fluorescence (ED-XRF) and X-ray photoelectron spectroscopy (XPS) techniques, respectively. Also, the structural and morphological characterizations of the substrates were performed by X-ray diffraction and scanning electron microscope (SEM), respectively. For alloys, the ED-XRF studies confirmed that the bulk compositions matched with the feed ratio, while the surface compositions were found to be rich in copper in the form of both elementary copper and copper oxide, as revealed by XPS studies. From the efficiency studies for different compositions prepared, it was found that 10% Ag-Cu alloy microflowers produced the maximum SERS intensity for resonant R6G molecules as probes. In fact, R6G evidences a 50-fold enhancement in SERS spectra with 10% alloy microflowers as against pure Ag microflowers. Using 1, 2, 3-benzotriazole as a nonresonant Raman probe, uniform enhancement factors on the order of ≈108 were achieved from different parts of the 10% Ag-Cu alloy microflower. The same substrate showed excellent Raman response for detecting R6G at very low concentrations such as 10 zM, leading to detection and analysis of SERS spectra from a single R6G molecule.

Archaeological applications of spectroscopic measurements. Compatibility of analytical methods in comparative measurements of historical Polish coins

The ED-XRF (energy-dispersive X-ray fluorescence) compact system was used to analyze selected Polish historical coins. The compact X-ray tube developed in the National Centre for Nuclear Research (NCBJ) was used as an X-ray source in the system designed for the ED-XRF studies. The XRF spectra were recorded with the Amptek SDD spectrometer. The elemental compositions of the coins have been determined using above mentioned system and the results were compared to those obtained with WD-XRF method. Other techniques such as SEM-EDX and XRD were also included into this work for comparison. The experimental data show that the X-ray system with transmission type X-ray tube with silver anode operating at 50 kV/30 µA which was developed in NCBJ together with the Amptek SDD spectrometer is an effective tool for chemical composition analyze of historical coins and can be successfully used in archaeometry.

Study of Lead Nitrate Doped PVA/PVP Blend Films using EDXRF and Complementary Techniques

Polyvinyl alcohol (PVA) − polyvinyl pyrrolidone (PVP) blend solutions were doped with different amounts of lead nitrate (Pb(NO3)2), in the doping range varying from 2.7 wt% up to 50.5 wt%. In this paper, the study of these films using Energy Dispersive X‐ray Fluorescence (EDXRF) technique in 2 π geometrical configuration is explained. In order to study K shell (Kαβ) X‐rays from the prepared films, cobalt‐57 radio‐isotope and thallium doped sodium iodide [NaI(Tl)] scintillation gamma/ x‐ray detector system with 1k MCA are used. The experiment was complemented by Scanning Electron Microscopy (SEM) coupled with Energy Dispersive X‐ray Spectroscopy (EDS). The SEM images revealed that the filler (Pb(NO3)2) causes significant micro‐structural changes in doped PVA/PVP blend films, revealing phase separation of the material into a polymer rich region and a dopant rich region at doping levels beyond 12.1 wt%. In addition to SEM, the EDXRF study is complemented by X‐Ray Diffraction (XRD) and Differential Scanning Calorimetry (DSC) scans on the Pb (NO3)2 doped PVA/PVP blend films.

Synthesis, characterisation and antimicrobial activity of manganese- and iron-doped zinc oxide nanoparticles

The present work reports study on antimicrobial activity of pure and doped ZnO nanocomposites. Polyvinyl pyrrolidone capped Mn- and Fe-doped ZnO nanocomposites were synthesised using simple chemical co-precipitation technique. The synthesised materials were characterised using transmission electron microscope (TEM), X-ray powder diffraction (XRD), energy dispersive X-ray fluorescence (EDXRF), Fourier transform infrared (FTIR) spectroscopy and ultraviolet (UV) visible spectroscopy. The XRD and TEM studies reveal that the synthesised ZnO nanocrystals have a hexagonal wurtzite structure with average crystalline size ∼7–14 nm. EDXRF and FTIR study confirmed the doping and the incorporation of impurity in ZnO nanostructure. The antimicrobial activities of nanoparticles (NPs) were studied against fungi, gram-positive and gram-negative bacteria using the standard disc diffusion method. The photocatalytic activities of prepared NPs were evaluated by degradation of methylene blue dye in aqueous solution under UV light irradiation. Experimental results demonstrated that ZnO NPs doped with 10% of Mn and Fe ions showed maximum antimicrobial and photodegradation efficiency in contrast with that of the 1% loading. The enhancement in antimicrobial effect and photocatalytic degradation is attributed to the generation of reactive oxygen species due to the synergistic effects of Mn and Fe loading.

Comparative Energy Dispersive X-Ray Fluorescence Studies on Two Representative Beach and River Sand Samples

Comparative Energy Dispersive X-Ray Fluorescence Studies on Two Representative Beach and River Sand Samples

On the use of bastnasite ore as a phosphor material

Bastnasite ore obtained from Indian Rare Earth (IRE) was investigated for its possible use as a phosphor material. The material was characterized by X-ray diffraction (XRD), energy dispersive X-ray fluorescence (EDXRF), photoacoustic spectroscopy (PAS), photoluminescence (PL) and electron paramagnetic resonance spectroscopy (EPR) techniques. XRD studies revealed the semi processed ore to be consisting of single phase CeO2 with no other impurities. EDXRF studies revealed the presence of ‘Th’ and traces of ‘Sm’ along with ‘Ce’ in the sample. PAS studies revealed the presence of strong charge transfer from oxygen to cerium in the system. PL studies confirmed the presence of at least four trivalent rare earths, viz. Sm, Eu, Dy and Tb in the system in trace quantities. The emission spectrum and decay time data were evaluated. It was observed that the rare earth ions are situated at distorted sites in the system surrounded by defect centers. EPR studies confirmed the presence of Ce3+in the system along with electron trapped in oxygen ion vacancies. CIE indices for the ore sample were evaluated and it was seen that the overall emission from the system was in the ‘magenta’ region of the visible spectrum. The emission intensities were also compared with that of commercial samples.

A Roman bronze statuette with gilded silver mask from Sardinia: an EDXRF study

A Roman bronze statuette from the 2nd Century BC was recovered from a nuragic sanctuary close to Florinas, in the north of Sardinia. The facial portion of the statuette is covered by a silver mask, partially gilded and attached to the bronze by tin-lead welding. The silver mask was carefully analyzed by portable energy-dispersive X-ray fluorescence (EDXRF), a non-destructive and non-invasive method. The aim of the analysis was to reconstruct the layered structure of the silver gilt mask, and to determine homogeneity and thickness of the gold, silver and lead–tin sheets. This is possible by using the internal ratio of the X-ray lines, i.e. starting from the surface, Au (Lα/Lβ), Ag (Kα/Kβ), Au-Lα/Ag-Kα and Pb (Lα/Lβ).The results were compared with those obtained with simulated X-ray spectra, obtained both experimentally and by using the Monte Carlo simulation technique.

A Brief Study of Cambodian Circular Earthwork Ceramics as

Prehistoric circular earthwork sites occurring across the basaltic plateau of eastern Cambodia/western Vietnam are internally homogenous in terms of site characteristics and material record. Energy Dispersive X-Ray fluorescence (EDXRF) analysis of several earthwork ceramic assemblage samples was studied in efforts to identify if ceramic production centers could be recognized within the circular site grouping. The EDXRF study provides an additional level of analysis to show that earthwork pottery was not being traded further south, into the Mekong Delta floodplains, and vice-versa.

Chemometric analysis of EDXRF measurements from fossil bone

Bone chemistry is an important source of biological and environmental information. Elemental compositions of archaeological and fossil bone have granted insight into the diets of ancient humans and other animals, as well as informing about the burial conditions of bone. Chemical studies of ancient bone can be performed non‐destructively with portable energy‐dispersive X‐ray fluorescence (EDXRF) spectrometers, which is particularly advantageous for on‐site analyses of museum specimens. Portable EDXRF instruments carry some analytical disadvantages, however, which may result in reduced precision or accuracy. Analytical shortfalls may be overcome by analysing inter‐sample trends in EDXRF spectral data instead of reported concentration measurements. We investigated the utility of statistically treating handheld EDXRF spectra from fossil bone and teeth, specifically the normalisation and mean centering of spectral data before principal component analysis. Fossil bone and tooth specimens were sourced from two Pleistocene localities in the Western Cape of South Africa, Swartklip 1 and Elandsfontein Main. Samples from the two localities could be distinguished using principal component score values, and coefficient loadings allowed chemical interpretation of the score clusters. Swartklip 1 samples were associated with elevated concentrations of Ca, indicating an additional Ca‐bearing mineral (i.e. calcite), whereas Elandsfontein Main samples were associated with elevated Fe and Sr concentrations. Fossil bone chemistry could be related to groundwater percolation through the sedimentary matrices of each locality. The methodology behind the case study presented here could readily be applied elsewhere and would be particularly useful to handheld EDXRF studies of museum specimens. Copyright © 2011 John Wiley & Sons, Ltd.

Energy-dispersive X-ray fluorescence study of elemental uptake in cauliflower

A 109Cd radioisotope-induced energy-dispersive X-ray fluorescence (EDXRF) study has been performed on samples of cauliflower consisting of the flower, the leaves and the associated root soil. The cauliflowers were collected from farms near the main dumping site of municipal solid waste in the city of Kolkata, India and also from uncontaminated farms about 50 km away from the city. A unified calibration approach was undertaken for the elemental analysis of the samples of widely varying matrices. The present study suggests that the elemental concentrations in the root soils and leaves of the samples vary from farm to farm, whereby the concentrations of Cu, Zn and Pb in root soils of MSW-contaminated farms are higher by almost an order of magnitude compared to uncontaminated farms. But, the most notable feature of this study is the strikingly similar elemental concentrations in the edible flower part of all samples irrespective of the type of soil.

Radioisotope‐induced EDXRF investigation of elemental uptake in cauliflower grown at MSW‐contaminated site

AbstractA 109Cd radioisotope‐induced energy dispersive X‐ray fluorescence (EDXRF) study has been performed on samples of cauliflower consisting of the flower, the leaves and the associated root soil. The cauliflowers are collected from farms near the main dumping site of municipal solid waste (MSW) in the city of Kolkata, India, and also from uncontaminated farms about 50 km away from the city. The systematic investigation is primarily aimed at achieving two correlated objectives. Firstly, a unified calibration approach is undertaken for the study tool viz., EDXRF spectrometer, through the use of same instrumental scattering constants for quantification in widely differing matrices like soil and plant. Quality control was done by quantitative reproduction of National Institute of Standards and Technology–Standard Reference Materials (NIST–SRMs). Subsequently, the second objective is to comparatively study elemental uptake in the cauliflower samples from contaminated and uncontaminated farms using the same calibration. This study suggests that the elemental concentrations in the root soils and leaves of the samples vary from farm to farm, whereby the concentrations of Cu, Zn and Pb in root soils of MSW‐contaminated farms are higher by almost an order of magnitude compared to uncontaminated farms. But the most notable feature of this study is the strikingly similar elemental concentrations in the edible flower part of all samples irrespective of the soil type. Plots of the ratio of concentrations of elements in leaf to soil and in flower to leaf, observed from the present EDXRF study suggests that a preferential uptake of elements takes place at different stages. Copyright © 2010 John Wiley & Sons, Ltd.

Energy dispersive X-Ray fluorescence determination of thorium in phosphoric acid solutions

Energy dispersive X-ray fluorescence studies on determination of thorium (in the range of 7 to 137 mg/mL) in phosphoric acid solutions obtained by dissolution of thoria in autoclave were made. Fixed amounts of Y internal standard solutions, after dilution with equal amount of phosphoric acid, were added to the calibration as well as sample solutions. Solution aliquots of approximately 2–5 µL were deposited on thick absorbent sheets to absorb the solutions and the sheets were presented for energy dispersive X-ray fluorescence measurements. A calibration plot was made between intensity ratios (Th Lα/Y Kα) against respective amounts of thorium in the calibration solutions. Thorium amounts in phosphoric acid samples were determined using their energy dispersive X-ray fluorescence spectra and the above calibration plot. The energy dispersive X-ray fluorescence results, thus obtained, were compared with the corresponding gamma ray spectrometry results and were found to be within average deviation of 2.6% from the respective gamma ray spectrometry values. The average precision obtained in energy dispersive X-ray fluorescence determinations was found to be 4% (1 σ). The energy dispersive X-ray fluorescence method has an advantage over gamma ray spectrometry for thorium determination as the amount of sample required and measurement time is far less compared to that required in gamma ray spectrometry.

EDXRF study of Indian punch-marked silver coins

Coins are important archaeological objects that can provide valuable information regarding coin minting methodology and provenance as well as politics and economics of the time. Punch-marked coins are the oldest known numismatics used in ancient India. 23 Indian punch-marked silver coins were analysed, for the first time, by using multi-elemental non-destructive energy dispersive X-ray fluorescence (EDXRF) technique. Our study reveals that silver, copper, iron, gold and lead are the significant constituents of the Indian punch marked silver coins, with minor/trace of elements like Ti, Cr, Co, Ni, As and Y also seems to indicate the fragmentation as well as the impoverishment of the power for the regimes that had produced the studied coins.

Effect of gallium on in vitro aortic valve cusp mineralization – EDXRF studies

The present studies were designed to determine the effect of gallium on the aortic valve cusp mineralization. The studies were conducted on aortic valves collected at autopsy from 35 donors. Each sample was incubated for 21 days in the mineralization-promoting medium, containing Ga at concentrations ranging from 0.0 to 8.0 μg/ml. The elemental compositions of the samples were measured using energy dispersive X-ray fluorescence (EDXRF) method. The concentrations of 14 elements were determined: Mg, Al, S, Cl, K, Ca, Mn, Fe, Ni, Cu, Zn, Ga, Br and Sr. Calcium contents and Ca/P ratios were considered as markers of the mineralization process. The aortic valves could be divided into two groups depending on the advancement of the mineralization process. The first group in which the process progressed and the second one which was resistant to mineralization. Ga was accumulated in both groups. The results demonstrated that Ga reduced the aortic valve mineralization in dose-dependent manner in the first group and did not influence the mineralization in the mineralization-resistant aortic valves.

EDXRF studies on Chinese Yue ware

AbstractAbstractThe major and trace element composition of Chinese Yue ware, widely recognized as the earliest Chinese porcelain (probably the earliest worldwide), is analysed using non‐destructive, energy‐dispersive x‐ray fluorescence (EDXRF). The results are subject to multivariate statistical analysis. Different compositional patterns were found for specimens from different production sites (Cixi, Ningbo, Shaoxin, Shangyu City, Zhejiang province). In particular the specimens excavated at Hangzhou palace, called Mise (mysterious colour) ware, can be identified by a small number of key element concentrations. Copyright © 2002 John Wiley & Sons, Ltd.

Quantitative EDXRF Studies of Obsidian Sources in Northern Hokkaido

Quantitative trace element data from six obsidian sources on the Japanese island of Hokkaido is presented. Previous work by Japanese scholars has utilized neutron activation analysis (NAA) focusing on the rare earth elements, or qualitative energy dispersive X-ray fluorescence (EDXRF). In this study, non-destructive EDXRF is used to generate trace element data for 9 elements. Bivariate plots of the incompatible trace elements (Ba, Rb, Sr, Y, and Zr) can be used to separate the obsidian sources in this study. Source separation was confirmed by using linear discriminant analysis. Stepwise discriminant analysis indicates that Ba, Sr, Rb, Ti, Y, and Zr are the most discriminating elements.

EDXRF study of Tupi-Guarani archaeological ceramics

A set of Indian Brazilian pottery fragments belonging to Tupi-Guarani tradition has been studied by EDXRF. The main objective was to characterize the ceramic paste, as well as the superficial layer of the ceramic fragments, in order to get qualitative information about the pigment composition of the plastic decoration. Energy Dispersive X-ray Fluorescence (EDXRF) methodology was employed to obtain the ceramic paste composition, as well as the superficial layer of the ceramic fragments. The experimental set-up consisted of 238Pu, 55Fe and 109Cd radioactive sources, a X-ray tube (at 15 kV, 40 mA, Mo target and Zr filter), a Si(Li) detector (30 mm 2, with a Be window) and a multichannel analyzer. X-ray spectra were analyzed using the AXIL program. A program based on the graphic polygonal representation method was developed and used to correlate the representative intensity data of each fragment. A low Ca content and a systematic presence of relatively high concentrations of Fe can characterize the ceramic pastes. Ti and Zr are also always present at high levels, and Ni, Cu and in some cases Zn at level of traces; Rb, Sr, Ba and Y are also present at low concentration. The black pigment in the pottery plastic decoration is due to the presence of Mn, the red pigment is due to the presence of Fe, while the white pigment is characterized by the presence of Ba. For the eleven fragments studied, the polygonal representation method points that the same materials were employed in the pottery production, and the pigments in the plastic decoration were obtained from different inorganic materials.