Total Reflection X-ray Fluorescence Spectrometry Research Articles

Mineral element composition of 27 Chinese dwarf cherry (Cerasus humilis (Bge.) Sok.) genotypes collected in China

SummaryConcentrations of ten mineral elements (P, S, K, Ca, Mn, Fe, Cu, Zn, Rb, and Sr) were determined in 27 genotypes of Chinese dwarf cherry using total reflection X-ray fluorescence spectrometry. The results indicated that Chinese dwarf cherry was a rich source of mineral elements, especially Ca, Fe, and Zn, with the highest concentrations being 524, 24.2, and 4.86 mg kg–1 FW in genotypes C-12-5-7, A-9-1-3, and E-20-2-2, respectively. Among the 27 Chinese dwarf cherry genotypes examined, the coefficients of variation were > 30% for Rb, Fe, Ca, Sr, Zn, Mn concentrations, and 25 – 30% for P, S, K, and Cu concentrations. Principal components analysis was applied to the data matrix to evaluate the analytical results. Three principal components (PC1 – PC3) accounted for 75.6% of the total variance. The 27 Chinese dwarf cherry genotypes studied have potential benefits for human nutrition and healthcare research, as well as for genetic biodiversity research.

The Impact of Bitumen Deposits on Groundwater Quality

Physico-chemical and elemental characteristics of groundwaters from a bitumen deposit area in Nigeria were determined with a view to assessing their levels of accumulation by the waters from the bitumen deposit and to provide a framework for the establishment of relationships between the chemistry of the mineral deposit and the groundwaters of the area. Physico-chemical parameters were measured using standard analytical procedures, while the elemental contents were determined by total reflection x-ray fluorescence spectroscopy technique. The results showed that the groundwaters have higher concentrations of elements (V, Cr, Mn, Cu, and Zn), which are known to be associated with hydrocarbon formation, than regular Nigerian groundwaters, apparently due to leaching of the elements from the bitumen deposit into the waters. Comparison of the analyzed parameters with their standard permissible values indicated that the waters were not potable. This was also corroborated by the values of their pollution index. Strong and significant positive correlations existed between some of the analyzed elements (K/Fe, K/Cu, Ca/Cr, V/Pb, Ni/Zn, Ni/Pb, Ca/Zn, V/Cr, V/Mn, V/Ni, V/Zn, Cr/Mn, Mn/Ni, and Ni/Cu), indicating a common source, chemical similarity, and/or common natural background levels in the waters. Elemental clustering results indicated that analyzed transition metals showed the closest inter-element clustering and were corroborated with their Pearson correlation matrices results, indicating chemical affinity and/or similar genetic origin. Strong positive correlations were shown by the results of the cross-plot analysis of the groundwater/oil sand water fraction and groundwater/bitumen suggesting inter-element correlations between them, and also establishing relationships between the groundwaters and the bitumen deposit in the area and that contamination of any components of the ecosystem would easily affect other ecosystems. These results could be used as a fingerprint for bitumen exploration elsewhere and also for similar mineral deposit settings, such as crude oil and coal deposits.

Concentration of Elements in Food: How Can It Reflect Impact of Environmental and Other Influencing Factors?

Abstract Element content of food is variable and can be influenced by different factors. The aim of the present study was to discover the linkage between macro- and microelement concentrations in food produced in Latvia, and possible impacts of environmental factors. More than 300 fresh food samples such as eggs, cottage cheese, honey, root vegetables, apple juice, apple wine were collected in the time period from 2009 to 2011. Samples were mineralised or analysed directly by appropriate method of quantitative analysis: atomic absorption spectrometry, inductively coupled plasma mass spectrometry or total reflection X-ray fluorescence spectrometry. Statistical analysis of data revealed that food elemental content can be influenced by sitespecific factors such as geographical origin, seasonality, environmental pollution.

The Novel Polishing Characteristics for GaAs Based Diode Lasers Wafer

A novel polishing technology for the GaAs based diode lasers wafer is presented. Designed for technological simplicity and minimum damage generated within the GaAs based diode lasers wafer. It combines GaAs based diode lasers wafer polishing with three conditions consisting of (1) removal of thermodynamically unstable species and (2) surface oxide layers must be completely removed after thermal cleaning, and (3) a smooth surface must be provide. Revolving ultrasonic atomization technology is adopted in the polishing process. At first impurity removal is achieved by organic solvents, second NH4OH:H2O2:H2O=1:1:10 solution and HCl:H2O2:H2O=1:1:20 solution in succession to etch a very thin layer, the goal of the step is removing contaminants and forming a very thin oxidation layer on the GaAs based diode lasers wafer, NH4OH:H2O=1:5 solution is used as the removed oxide layers in the end. The effectiveness of the process is demonstrated by operation of GaAs based diode lasers wafer, characterization of the oxide composition was carried out by X-ray photoelectron spectroscopy,and surface morphology was observed by total reflection X-ray fluorescence spectroscopy and atomic force microscope. The research results show that the polished surface without contamination, and the n-side surface are very smooth.

Vapor phase treatment–total reflection X-ray fluorescence for trace elemental analysis of silicon wafer surface

Vapor phase treatment (VPT) was under investigation by the International Organization for Standardization/Technical Committee 201/Working Group 2 (ISO/TC201/WG2) to improve the detection limit of total reflection X-ray fluorescence spectroscopy (TXRF) for trace metal analysis of silicon wafers. Round robin test results have confirmed that TXRF intensity increased by VPT for intentional contamination with 5×109 and 5×1010atoms/cm2 Fe and Ni. The magnification of intensity enhancement varied greatly (1.2–4.7 in VPT factor) among the participating laboratories, though reproducible results could be obtained for average of mapping measurement. SEM observation results showed that various features, sizes, and surface densities of particles formed on the wafer after VPT. The particle morphology seems to have some impact on the VPT efficiency. High resolution SEM observation revealed that a certain number of dots with SiO2, silicate and/or carbon gathered to form a particle and heavy metals, Ni and Fe in this study were segregated on it. The amount and shape of the residue should be important to control VPT factor.

TXRF analysis of soils and sediments to assess environmental contamination

Total reflection x-ray fluorescence spectroscopy (TXRF) is proposed for the elemental chemical analysis of crustal environmental samples, such as sediments and soils. A comparative study of TXRF with respect to flame atomic absorption spectroscopy and inductively coupled plasma optical emission spectroscopy was performed. Microwave acid digestion and suspension preparation methods are evaluated. A good agreement was found among the results obtained with different spectroscopic techniques and sample preparation methods for Cr, Mn, Fe, Ni, Cu, and Zn. We demonstrated that TXRF is suitable for the assessment of environmental contamination phenomena, even if the errors for Pb, As, V, and Ba are ingent.

Growth rate affects the responses of the green alga Tetraselmis suecica to external perturbations

Acclimation to environmental changes involves a modification of the expressed proteome and metabolome. The reproductive advantage associated with the higher fitness that acclimation provides to the new conditions more than compensates for the costs of acclimation. To exploit such an advantage, however, the duration of the perturbation must be sufficiently long relative to the growth rate. Otherwise, a selective pressure may exist in favour of responses that minimize changes in carbon allocation and resource use and do not require reversal of the acclimation after the perturbation ceases (compositional homeostasis). We hypothesize that the choice between acclimation and homeostasis depends on the duration of the perturbation relative to the length of the cell cycle. To test this hypothesis, we cultured the green alga Tetraselmis suecica at two growth rates and subjected the cultures to three environmental perturbations. Carbon allocation was studied with Fourier transform infrared (FTIR) spectroscopy; elemental stoichiometry was investigated by total reflection X-ray fluorescence (TXRF) spectroscopy. Our data confirmed that growth rate is a crucial factor for C allocation in response to external changes, with a higher degree of compositional homeostasis in cells with lower growth rate.

Soil and foliar application of selenium in rice biofortification

Selenium (Se) is essential for humans and animals because of its antioxidant properties, which form part of a series of chemical reactions. The aim of this study was to evaluate the effect of different Se application forms and sources on rice growth, grain yield, and rice Se concentration and accumulation, as well the content of N, P, Mg, S, B, Cu, Fe, Mn, and Zn in rice grains. The experiment was carried out in a greenhouse with 4-dm3 pots containing a sandy clay loam Red-Yellow Latosol. The experimental design was a completely randomized 2×2×2 factorial scheme (two Se doses×two forms of Se application, soil or foliar×two Se sources, selenate or selenite), with five replicates. Selenium in rice plants was analyzed by total reflection X-ray fluorescence spectrometry (TXRF). The results shows that soil selenate application was more effective for shoot dry matter production and grain Se accumulation than selenite. Foliar application of both selenate and selenite increased grain yield. This study provides useful information concerning agronomic biofortification of rice, showing that both soil and foliar Se application could be used for increasing Se content in edible parts, which could result in health benefits.

Research review trends of food analysis in Latvia: major and trace element content

The current paper involves overview of several studies concerning quantitative major and trace element analysis of different food samples, such as products of plant origin, e.g., locally grown vegetables (carrots, onions, potatoes) and products of animal origin derived with or without processing (cottage cheese, eggs, honey). Food samples were collected over the territory of Latvia in the time period 2009-2012. Sample pre-treatment was chosen according to the product specifics but mostly wet mineralization with concentrated nitric acid was applied. Analysis of major elements (e.g., Ca, Fe, K, Mg, Na) and trace elements (e.g., As, Cd, Co, Cr, Cu, Ni, Pb, Se, Zn) was performed by appropriate quantitative analytical technique: atomic absorption spectrometry, inductively coupled plasma mass spectrometry or total reflection X-ray fluorescence spectrometry. Not only the influence of environmental factors (e.g., geographical or seasonal impact) was detected in element dissemination in food, also botanical origin (if applicable) and applied agricultural praxis, product processing and storage specifics were found to be important. Possible food contamination by potentially toxic elements can be associated mostly with the consequences of anthropogenic activities. The studies revealed the significance of food research in the context of environmental science.

Potentialities of total reflection X-ray fluorescence spectrometry in environmental contamination: Hair of owned dogs as sentinel of arsenic exposure

Abstract Arsenic concentrations in dog hair were measured in 50 pets living in Barrio Los Alamos, La Matanza district, Buenos Aires Province, Argentina. The aim of this work was to study the potential use of domestic canine hair as a biomarker of chronic exposure to arsenic by total reflection X-ray fluorescence spectrometry. Arsenic quantification in the samples was performed after a simple sample preparation procedure consisting in an in situ microwave digestion. Independently of genre, age and breed, hair of dogs from Los Alamos had significantly higher arsenic concentrations compared to a set of 10 dogs used as controls coming from an arsenic-free area. These levels found in hair (24 ± 2 μg As gDW − 1 ) indicate chronic exposure of dogs and suggest a similar situation in cohabitant humans. Results of this study encourage the potential use of pets as monitor targets of environmental metal contamination.

Determination of platinum group metal catalyst residues in active pharmaceutical ingredients by means of total reflection X-ray spectrometry

The control of metal catalyst residues (i.e., platinum group metals (PGMs)) in different stages of the manufacturing processes of the active pharmaceutical ingredients (APIs) and, especially, in the final product is crucial. For API specimens, there are strict guidelines to limit the levels of metal residues based on their individual levels of safety concern. For PGMs the concentration limit has been established at 10mg/kg in the API.Therefore great effort is currently being devoted to the development of new and simple procedures to control metals in pharmaceuticals.In the present work, an analytical methodology based on benchtop total reflection X-ray fluorescence spectrometry (TXRF) has been developed for the rapid and simple determination of some PGM catalyst impurities (Rh, Pd, Ir and Pt) in different types of API samples. An evaluation of different sample treatments (dissolution and digestion of the solid pharmaceutical samples) has been carried out and the developed methodologies have been validated according to the analytical parameters to be considered and acceptance criteria for PGM determination according to the United States Pharmacopeia (USP). Limits of quantification obtained for PGM metals were in the range of 2–4mg/kg which are satisfactory according to current legislation. From the obtained results it is shown that the developed TXRF method can be implemented in the pharmaceutical industries to increase productivity of the laboratory; offering an interesting and complementary analytical tool to other atomic spectroscopic methods.

Ultrasound-assisted single extraction tests for rapid assessment of metal extractability from soils by total reflection X-ray fluorescence

In this work, ultrasound-assisted extraction (UAE) was employed for acceleration of metal extraction from soil samples. After extraction, multielemental analysis (Cr, Mn, Fe, Ni, Cu, Zn and Pb) of EDTA and acetic acid extracts was performed by total reflection X-ray fluorescence spectrometry (TXRF).High-intensity ultrasonic processors, i.e. the ultrasonic probe (50W) and the cup-horn sonoreactor (200W) were applied. Both ultrasonic procedures were compared with a miniaturized version of the single extraction scheme proposed by the Standards, Measurements and Testing program (SM&T).The extraction time with EDTA was reduced from 1h (conventional procedure) to 2min (ultrasonic probe) or to 10min (cup-horn sonoreactor). The time required for acetic acid extraction was also reduced from 16h (conventional procedure) to 6min (ultrasonic probe) or to 30min (cup-horn sonoreactor). In addition, the amount of sample and extractants was drastically reduced as a result of the miniaturization implemented in the developed approaches. The combination of UAE and TXRF allows assessing the potential metal mobility and bioavailability in a simple way.

Evaluation of airborne particulate matter pollution in Kenitra City, Morocco

Two size fractions of atmospheric particulate matter < 2.5 µm and 2.5-10 µm were collected in Kenitra City from February 2007 to February 2008. The sampling was done using a Gent Stacked sampler on nuclepore polycarbonate filters and the collected filters were analyzed using Total Reflection X-Ray Fluorescence (TXRF) and Atomic Absorption Spectroscopy (AAS). The particulate matter trends show higher concentrations during the summer as compared to other seasons. The highest concentrations were obtained for Ca in coarse particles and Fe for fine particles. However, the lowest concentrations were observed for Cd in both particulate sizes. The principal component analysis (PCA) based on multivariate study enabled the identification of soil, road dust and traffic emissions as common sources for coarse and fine particles.

Рентгенофлуоресцентное определение элементов в воде с использованием спектрометра с полным внешним отражением

In the literature review the advances are discussed achieved in the application of total reflection X-ray fluorescence spectrometry (TXRF) to study the elemental compositions of different types of water. The special features of the main stages of analysis are described. Particular attention is given to the equipment, sample preparation procedure and error sources in TXRF of waters with various compositions. The examples of matrix effects and spectral interferences in TXRF and metrological characteristics of technique s are presented. Key words : Total reflection X-ray fluorescence analysis, TXRF, water. (Russian) DOI: http://dx.doi.org/10.15826/analitika.2013.17.2.001 G.V. Pashkova, A.G. Revenko Institute of the Earth’s Crust, SB RAS , Irkutsk, Russia

Insitu ultrasound-assisted synthesis of Fe3O4 nanoparticles with simultaneous ion co-precipitation for multielemental analysis of natural waters by total reflection X-ray fluorescence spectrometry

In this work, in situ ultrasound-assisted magnetite synthesis with simultaneous ion co-precipitation (UAMS-SIC) was applied to magnetic solid-phase extraction (MSPE) of Cu, Zn, Ge, As, Se, Re, Au, Hg, Tl, Bi and Pb. The magnetic solid phase (MSP) enriched with metal ions was directly analyzed by total reflection X-ray fluorescence (TXRF). Magnetite nanoparticles (Fe3O4 NPs) were synthesized by sonochemical treatment of a solution containing Fe(II) and Fe(III) in the presence of target analytes so that these are trapped by occlusion or surface adsorption during the formation of Fe3O4 NPs. In situ synthesized Fe3O4 NPs were easily separated from the aqueous matrix by applying an external magnetic field, and hence, no filtration or centrifugation steps were necessary. A 10 μL aliquot of MSP was deposited onto a sample quartz glass siliconized carrier and analyzed by TXRF, thus avoiding the elution step. The effect of the Fe(II):Fe(III) molar ratio, total mass of Fe in the MSP, ultrasound amplitude, time and interfering ions on the extraction efficiency of the metal ions was investigated. Detection limits ranged from 0.3 to 26 μg L−1 depending on the metal ion. Enrichment factors (EFs) in the range 8–180 were achieved. A recovery study carried out on spiked samples showed recoveries in the range 89–109% with relative standard deviations below 10% (N = 5). An effective, fast and sensitive procedure that can be used for field analysis is accomplished. A comprehensive characterization of in situ synthesized Fe3O4 NPs was carried out by atomic force microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. Finally, a co-precipitation mechanism for trace metal ions with this novel synthesis of nanosized magnetite is approached using the Berthelot–Nernst and the Doerner–Hoskins laws.

Food and Environment: Trace Element Content of Hen Eggs from Different Housing Types

Eleven trace elements (Ba, Cu, Fe, Mn, Ni, Pb, Rb, Se, Sr, V, Zn) were quantitatively determined in hen egg samples collected from different poultry housing types (large-scale poultry farms, organic farms and domestic farms) over the territory of Latvia. Samples were wet digested and quantitatively analysed by total reflection X-ray fluorescence spectrometry (TXRF). The accuracy of analytical method was verified with analysis of certified reference material NCS ZC73017 (GSB-10)-Apple. The most variable range of concentrations and the highest content of elements were determined for hen egg samples derived from organic farms, while egg samples from domestic farms and poultry farms mostly contained lower content of elements. That can be attributed not only to poultry feed specifics within different housing types but also to the impact of environmental factors.

Dispersive micro solid-phase extraction using multiwalled carbon nanotubes combined with portable total-reflection X-ray fluorescence spectrometry for the determination of trace amounts of Pb and Cd in water samples

In this paper the combination of dispersive micro solid-phase extraction (DMSPE), using multiwalled carbon nanotubes (MWCNTs) as solid sorbents, with total-reflection X-ray fluorescence spectrometry (TXRF) is proposed for preconcentration and determination of lead and cadmium ions in water samples. The proposed sample preparation is quite simple and economic. After the sorption processes of the metals on the MWCNTs, the aqueous sample is separated by centrifugation and the metal loaded MWCNTs are suspended using a small volume of an internal standard solution and analyzed directly by TXRF. Parameters affecting the extraction process (complexing agent, pH of the aqueous sample, amount of MWCNTs) and TXRF analysis (volume of the deposited suspension on the reflector, drying mode, and instrumental parameters) have been carefully evaluated to test the real capability of the developed methodology for the determination of Cd and Pb at trace levels. For both elements the linear range is observed up to 50 ng mL−1. Under optimized conditions detection limits are 1.0 ng mL−1 and 2.1 ng mL−1 for Cd(II) and Pb(II) ions, respectively. Both of the examined elements can be determined with quantitative recoveries (ca. 100%) and with an adequate precision (RSD = 6.0% and 10.5% for Cd(II) and Pb(II), respectively). Our results give insight into the possibilities of the combination of DMSPE and TXRF for trace metal determination in different types of environmental waters (sea, river and waste water).

Elemental concentration analysis in prostate tissues using total reflection X-ray fluorescence

Prostate cancer (PCa) currently represents the second most prevalent malignant neoplasia in men, representing 21% of all cancer cases. Benign Prostate Hyperplasia (BPH) is an illness prevailing in men above the age of 50, close to 90% after the age of 80. The prostate presents a high zinc concentration, about 10-fold higher than any other body tissue. In this work, samples of human prostate tissues with cancer, BPH and normal tissue were analyzed utilizing total reflection X-ray fluorescence spectroscopy using synchrotron radiation technique (SR-TXRF) to investigate the differences in the elemental concentrations in these tissues. SR-TXRF analyses were performed at the X-ray fluorescence beamline at Brazilian National Synchrotron Light Laboratory (LNLS), in Campinas, São Paulo. It was possible to determine the concentrations of the following elements: P, S, K, Ca, Fe, Cu, Zn and Rb. By using Mann–Whitney U test it was observed that almost all elements presented concentrations with significant differences (α=0.05) between the groups studied.

Exhaled breath condensate as a biomonitor for metal exposure: a new analytical challenge

The study of exhaled breath condensate (EBC) obtained by cooling exhaled air under conditions of spontaneous breathing is considered one of the areas with higher interest in respiratory health research. The use of EBC for elemental determination in occupational exposure requires a standard methodological procedure to implement its practice in occupational studies. EBC is an inhomogeneous sample with organic and particulate matter in suspension, which may hamper analytical results reliability. Total reflection X-ray fluorescence and inductive coupled-plasma mass spectrometry (ICP-MS) techniques were chosen as both are multielemental, require small sample volumes and have appropriate detection limits. Estimation of the overall uncertainty in both techniques was carried out using a pool of EBC collected from a group of workers of a lead processing industry to perform precision and trueness studies for K, Mn, Cu, Cd, Sb and Pb. Precision was estimated in terms of repeatability using the native EBC sample pool and trueness in terms of recovery obtained from spiking aliquots of the EBC pool with K, Mn, Cu, Cd, Sb and Pb at different concentrations. Recovery was the most significant contribution to total uncertainty. The overall uncertainties obtained for ICP-MS enabled to discriminate between groups of individuals exposed to different levels of contaminants. Therefore EBC proved to be useful in human biomonitoring.

Elemental composition of wheat, common buckwheat, and tartary buckwheat grains under conventional production

The elemental composition of cereal and pseudocereal grain is believed to significantly affect the portions of the minerals supplied for particular human populations. Therefore, care needs to be taken to improve the availability of the essential elements and to decrease unwanted metal accumulation in edible plant parts. In the present study, we have investigated the element accumulation in the grain of wheat (Triticum aestivum L.), common buckwheat (Fagopyrum esculentum Moench), and tartary buckwheat (Fagopyrum tataricum (L.) Gaertn.), harvested from the same field under conventional grain production. Soil and grain element compositions were analysed using energy dispersive X-ray fluorescence spectrometry and total reflection X-ray fluorescence spectrometry. The wheat grain shows significantly higher (p &lt; 0.05) higher element concentrations than both of the buckwheat species tested. The contents of elements in 100 g grain were higher than the concentrations listed in the literature for wheat and buckwheat flours, which indicates significant losses of elements during milling and polishing. Concerns are raised due to the high and unwanted metal ac- cumulation in wheat and buckwheat. The data indicate that both of these buckwheat species accumulate less metal contaminants when compared to wheat.