Search

The aim of the research presented in this article is to select best internal standard for use in the direct routine analysis of L series elements concentration in water samples by applying the Total Reflection X-ray Fluorescence (TXRF) technique. In the study, aqueous reference materials were used to determine detection limits of the following potentially toxic elements: Pd, Ag, Cd, In, Sn, Sb, Ba, Nd, Gd, Er, Ta, W, Tl, Pb, and Bi. The elements were in the form of: monoelemental, two-elemental (Ba and Ti, W and Cu, Pb and As), and multielemental solutions with different concentrations of elements. The detection limits of chemical elements were analyzed using various internal standards (Co, Ga, Nd, and Sr), and the TXRF spectrometers with the Mo-anode and W-anode X-ray tubes. For the analyzed L series elements, the detection limits, normalized to the same measurement time (t = 1000 s), were calculated. Finally, the internal standards were proposed to analyze the studied elements for two different X-ray sources (the Mo-anode and W-anode X-ray tubes). The detection limits were also discussed with respect to the ISO 20289:2018 standard. Based on the measurements, the relative sensitivities were calculated for each of the applied TXRF spectrometers. [Display omitted] • Internal standard (IS) selection in analyzing of L series elements in water by TXRF. • The detection limits of L series elements were analyzed using Mo-TXRF and W-TXRF. • In analysis various internal standards (Co, Ga, Nd and Sr) were applied. • IS proposed for analysis of the studied elements for two different X-ray sources. • Relative sensitivities calculated for each applied TXRF spectrometer. [ABSTRACT FROM AUTHOR]

This paper aims to evaluate the product contamination by elemental impurities during the mechanochemical synthesis of praziquantel (PZQ) co-crystal, polymeric dispersion and cyclodextrin complex by grinding. To assess that, PZQ was co-ground with malic acid (MA), Poloxamer F-127 (F-127) and hydroxypropyl-β-cyclodextrin (HPβCD) in high-energy vibrational mills using stainless steel and agate grinding tools, applying different processing time (30 and 90 min). Differential scanning calorimetry and X-ray powder diffraction confirmed the formation of the targeted products, regardless of applied processing time and grinding tool type. After digestion of the solid powder products, the levels of selected elemental impurities were analysed by inductively coupled plasma mass spectrometry (ICP-MS). The analysis revealed that the content of Mg, Ca, and V are below the limit of quantification in all samples analysed. The contents of P and Na are not related to the type of ball mill and reaction time, but to the starting materials themselves, considering that Na is found in HPβCD and MA, while P was found in F-127. The detected Si impurities in the co-ground products can be related to the use of the agate balls and jars, while the presence of Cr and Fe can be related to the use of the stainless steel grinding tools. The risk assessment showed that the oral administration of the prepared co-ground products in quantities corresponding to regular PZQ oral doses resulted in only insignificant exposure to Cr. Finally, the use of agate grinding tools should be preferred, as administration of such products results in lower Cr exposure. The presented elemental impurities did not lead to any significant drug degradation as PZQ content at the end of the six-month testing period was still in the range of 95–105 % of the initial content. Regardless, ICP-MS analysis of the elemental impurities should be considered in regular quality control procedures in the development and production of novel pharmaceutical products prepared by grinding. • Product impurity profile is related to the material of which the grinding tools are made. • Grinding tools type did not affect the preparation and stability of the targeted products. • Si impurities in the co-ground products can be related to the use of agate balls and jars. • The presence of Cr and Fe relates to the use of stainless steel grinding tools. • The use of agate grinding tools is preferred, resulting in lower Cr exposure. [ABSTRACT FROM AUTHOR]

The aim of the present work is the development of a simple, sensitive and sustainable EDXRF method for the determination of trace amounts of sulfur in biodiesel samples. In this method, the deposition of several microliters of sample onto an organic thin layer and the analysis of the resulting adsorbed biodiesel spot by benchtop EDXRF is proposed. A careful study was performed to select the volume and the best solid support to deposit biodiesel samples, including filters made of different materials (glass fiber, Nylon, cellulose, paper) and a commercial disposable absorbent pad (UltraCarry, Rigaku). A critical issue that limits the use of most of these solid supports was the relative high blank signals that hamper the determination of sulfur at trace levels. Finally, it was found that best strategy was the deposition of 50 μL of biodiesel on the UltraCarry sample retainer. Operating conditions for EDXRF measurements were also evaluated to obtain the best instrumental sensitivity for sulfur determination (Excitation: 20 kV, no primary filter, measurement time: 300 s). Using the best analytical conditions the quantification limit of the method was 7 mg kg−1 of sulfur. This value is even better than the one reported in the ASTM D4294 method (LOQ: 16.0 mg kg−1) but using a sample amount 100 times smaller. The linearity was confirmed in the range of 10–100 mg kg−1by analyzing a set of commercial biodiesel standards. Accuracy and precision of the results, evaluated by the analysis of samples prepared with the same matrix as the standards, with levels of 20, 40 and 75 mg kg−1of sulfur, and processed as unknowns, proved acceptable (Recoveries: 94.3–110.6%, RSD: 10.8–13.6%, n = 3) for the intended purpose. Overall, the performance of the method developed is promising and it could be used to determine trace amounts of sulfur in biodiesel samples in a simple, sustainable and cost-effective way. Furthermore, since the original sample is adsorbed onto a solid support, repeat confirmatory analyses on the same specimen, if needed, can be carried out. Unlabelled Image • A EDXRF method for S determination at trace levels in biodiesel samples is proposed. • Sample preparation entails formation of dried biodiesel spots. • Limit of quantification of sulfur in biodiesel is 7 mg kg−1. • Quantification by biodiesel standards containing S in the range of 10–100 mg kg−1. • Possibility of sample-reanalysis overtime. [ABSTRACT FROM AUTHOR]

The aim of the work is to present a systematic evaluation of the analytical capabilities of the new X-ray fluorescence facility jointly operated between the International Atomic Energy Agency and the Elettra Sincrotrone Trieste for multipurpose total reflection X-ray fluorescence analysis. The analytical performance of the XRF beamline end-station (IAEAXspe) was systematically evaluated under TXRF excitation geometry by analyzing different types of aqueous (lake, waste and fresh water) and solid (soil, vegetal, biological) certified reference materials using an excitation energy of 13.0 keV (for the purpose of multielemental analysis). The results obtained for both types of samples in terms of limits of detection and accuracy were also compared with those obtained using laboratory X-ray tube based TXRF systems with different features (including Mo and W X-ray tube systems). Taking advantage of the possibility to work under high vacuum, the IAEAXspe set-up instrumental sensitivity was also determined using an excitation energy of 6.2 keV to explore the possibilities for light elements determination. A clear improvement of the element detection limits is achieved when comparing this facility to conventional X-ray tube based TXRF systems highlighting the benefits of using the monoenergetic synchrotron exciting radiation and the ultra-high vacuum chamber in comparison with conventional laboratory systems. The results of the present work are discussed in view of further exploitation of the facility for different environmental and biological related applications. [ABSTRACT FROM AUTHOR]

Sewage sludge is used as a fertilizer replacement in agricultural soils for its chemical properties, such as organic matter content, and for its capability to improve physical soil characteristics like porosity. This is also an appealing disposal option for residue whose production is increasing worldwide. However, there is some concern about the presence of potentially toxic elements (PTEs) that can accumulate in soils and become available for crops. In this work, a study was conducted to evaluate the extractability and crops transfer of thirteen PTEs from soils that had been amended with biosolids each year for 15 years as a regular agricultural practice. The study was conducted with barley (winter cereal) and maize (spring cereal) crops. After this long period, an increase in the amount of Pb, Hg, Zn and Ag in soils amended by biosolids was confirmed. However, it is important to emphasize that the PTE total content in croplands was still far below the thresholds established by US and European regulations. Statistically significant differences were also found between the soils fertilized with biosolids and other treatments compared with the potential phytoavailable amount of Cu, Se, Sb and especially for As and Zn, by a DTPA leaching test. Despite these results, the concentration of PTEs in the barley and maize grains grown in fields repeatedly amended with biosolids was not statistically different from those grown with chemical fertilization, except for As in barley grains. In this case, a significant correlation was found between the DTPA-extractable As content in soils and the total content in grains (r = 0.83). [ABSTRACT FROM AUTHOR]

In this work, an analytical methodology in combination with a low power benchtop total reflection X-ray fluorescence (TXRF) system has been developed for multi-elemental analysis of vegetal materials. An easy and rapid sample preparation consisting in suspending 20 mg of sample in de-ionized water showed to be the most suitable for this kind of samples. However, for comparison purposes, two digestion procedures were also applied. A set of fifteen certified reference materials and three real vegetal samples were employed for the quantitative determination of K, Ca, Mn, Fe, Cu, Zn, Br, Rb, Sr, Pb, As and Sn. All the parameters affecting sample preparation and TXRF measurements conditions were carefully evaluated. Accurate and precise results were obtained for mid-high Z elements (Mn-Sr) using internal standardization as quantification approach, while for light Z elements (K and Ca), due to absorption effects, an improvement of analytical results by external calibration was necessary. [ABSTRACT FROM AUTHOR]

In the present contribution, a simple and inexpensive method for the determination of hexavalent chromium in aqueous solutions was developed. The analytical methodology consists of the combined use of a low cost Cr(VI) isolation procedure followed by the analysis using total reflection X-ray spectrometry (TXRF). The liquid-liquid microextraction procedure (LLME) used is based on the formation of an ion-pair between the cationic part of the surfactant cetyltrimethylammonium bromide (CTAB) and the corresponding anionic Cr(VI) species, which is extracted in few microliters of chloroform. TXRF analysis can be performed directly by deposition of 15 μL of the preconcentrated sample on a sample carrier, without any additional sample treatment. Experimental parameters affecting Cr(VI) extraction and TXRF analysis were studied in detail. Under optimum conditions, a good linearity was obtained in the range of 5–5000 μg/L with a limit of detection for hexavalent chromium of 0.9 μg/L. This fact opens the possibility of Cr determination in aqueous samples characterized by different concentration levels. The methodology was successfully applied for the determination of Cr(VI) species in different type of water matrices (tap, well, river and sea water) as well as industrial aqueous samples including in industrial waste water from a galvanic industry and aqueous clinker extracts. For comparison purposes, the determination of Cr(VI) in industrial samples was also carried out by using the colorimetric method EPA Method 7196. [Display omitted] • Simple and inexpensive method for Cr (VI) determination in aqueous samples. • Combined use of microextraction using a cationic surfactant and TXRF analysis. • Good linearity (5–5000 μg/L) with a limit of detection of 0.9 μg/L Cr (VI). • Application to water samples as well as industrial waste waters and aqueous extracts. [ABSTRACT FROM AUTHOR]

Recent technological improvements have led to a widespread adoption of benchtop total reflection X-ray fluorescence systems (TXRF) for analysis of liquid samples. However, benchtop TXRF systems usually present limited sensitivity compared with high-scale instrumentation which can restrict its application in some fields. The aim of the present work was to evaluate and compare the analytical capabilities of two TXRF systems, equipped with low power Mo and W target X-ray tubes, for multielemental analysis of wine samples. Using the Mo-TXRF system, the detection limits for most elements were one order of magnitude lower than those attained using the W-TXRF system. For the detection of high Z elements like Cd and Ag, however, W-TXRF remains a very good option due to the possibility of K-Lines detection. Accuracy and precision of the obtained results have been evaluated analyzing spiked real wine samples and comparing the TXRF results with those obtained by inductively coupled plasma emission spectroscopy (ICP-OES). In general, good agreement was obtained between ICP-OES and TXRF results for the analysis of both red and white wine samples except for light elements (i.e., K) which TXRF concentrations were underestimated. However, a further achievement of analytical quality of TXRF results can be achieved if wine analysis is performed after dilution of the sample with de-ionized water. [ABSTRACT FROM AUTHOR]

Elemental content plays an important role in biological processes, and so, the multielemental analysis of human tissue samples is required in biomedical research. Still, the small amount of available biological samples and the adipose content of the samples can be major setbacks for the accurate determination of elemental content. In this study, we explored the potential of several analytical approaches combined with total reflection X-ray fluorescence spectrometry (TXRF) for multielemental analysis of human tissues with different adipose content (colon, heart, liver, lung, muscle, intestine, skin, stomach, uterus, bladder and aorta). The capabilities and limitations of different sample treatment procedures (suspension and acidic digestion) and two TXRF systems with different anode configurations (Mo and W X-ray tubes) have been evaluated for such purpose. Results showed that for tissues with a higher fat content (e.g., skin, and intestine) the best strategy was the acidic digestion of the sample before TXRF analysis. However, for other tissues, acceptable results were obtained by suspending 20 mg of powdered material in 1 mL of 2 M nitric acid. A further enhancement of the limits of detection and accuracy of the results was achieved if using Mo-TXRF systems, especially for the determination of low Z elements (e.g., K, and Ca) and of elements present at low concentrations (e.g., Cu) in the human tissues. Finally, results by TXRF analysis were compared with those obtained with μ-EDXRF and ICP-OES, and a good agreement was obtained. [Display omitted] • Good quantitative compromise between techniques for medium-Z elements. • Gauging adipose content through EDXRF for decision-making in TXRF sample preparation. • Tissues with high adipose content require sample digestion procedures. [ABSTRACT FROM AUTHOR]

Abstract: 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. [Copyright &y& Elsevier]

Abstract: This work was aimed at improving the instrumental sensitivity and detection limits for Cd determination in liquid samples by using conventional Wavelength Dispersive X-ray Fluorescence (WDXRF) instrumentation equipped with Rh-anode X-ray sources. The fact that the background is drastically reduced when using activated membranes as a preconcentration tool to collect Cd from liquid samples permits an improvement of the sensitivity compared with the direct analysis of liquid samples. Instrumental WDXRF parameters, as well as the study of Cd-K and Cd-L series spectral lines, were evaluated to select the best conditions for Cd quantitation. The Cd-Lα spectral line was found to be the best choice in terms of sensitivity and repeatability. The calculated detection limit when this spectral line was used to carry out the measurements was 0.17 mg L−1 Cd, which is suitable for Cd determination in most liquid samples involved in environmental studies. [Copyright &y& Elsevier]

In-situ monitoring of potentially toxic elements in mining water samples is of special relevance in order to evaluate the environmental impact of abandoned mining activities. However, it is difficult to develop suitable analytical methods for this purpose considering the complexity of mining water samples matrix as well as the limited sensibility of conventional filed portable X-ray fluorescence spectrometry systems (pXRF). In the present contribution, a simple, sustainable and reliable triaxial pXRF method (3pXRF) is proposed for multielemental analysis of mining water samples. In this method, several microliters of sample are deposited onto a commercial filter paper retainer and after drying, the loaded filter is directly analyzed in the field using a laboratory pXRF with orthogonal triaxial geometry (p3XRF). This geometry reduces the background of the measured spectra improving peak-background ratios in comparison with conventional pXRF systems. Using the best analytical conditions (sample deposition volume of 200 μL and 600 s as measurement time), limits of detections were in the low mg∙L−1 range and therefore suitable considering the expected high metal concentration in mining water samples. Acceptable accuracy and precision of the results was obtained in comparison with laboratory techniques such as inductively coupled plasma optical emission spectrometry and total reflection X-ray fluorescence spectrometry but with the possibility of in-situ measurements in the field. The developed method was applied to the analysis of different types of mine water samples (stream waters, drainage water tanks and mining lake waters) collected in the mining districts of Tinoca (Portugal) and Cartagena-La Unión (Spain). Unlabelled Image • Simple, sustainable and reliable method for analysis of Acid Mine Drainage waters • Fast and cost-effective screening of mining water composition in the field • Analysis of water loaded filters using portable X Ray Fluorescence. • Accuracy and precision suitable and comparable with ICP and TXRF [ABSTRACT FROM AUTHOR]

In this work, a Total Reflection X-ray fluorescence (TXRF) spectrometry based quantitative methodology for elemental characterization of liquid extracts and solids belonging to old building materials and their degradation products from a building of the beginning of 20th century with a high historic cultural value in Getxo, (Basque Country, North of Spain) is proposed. This quantification strategy can be considered a faster methodology comparing to traditional Energy or Wavelength Dispersive X-ray fluorescence (ED-XRF and WD-XRF) spectrometry based methodologies or other techniques such as Inductively Coupled Plasma Mass Spectrometry (ICP-MS). In particular, two kinds of liquid extracts were analysed: (i) water soluble extracts from different mortars and (ii) acid extracts from mortars, black crusts, and calcium carbonate formations. In order to try to avoid the acid extraction step of the materials and their degradation products, it was also studied the TXRF direct measurement of the powdered solid suspensions in water. With this aim, different parameters such as the deposition volume and the measuring time were studied for each kind of samples. Depending on the quantified element, the limits of detection achieved with the TXRF quantitative methodologies for liquid extracts and solids were set around 0.01–1.2 and 2–200 mg/L respectively. The quantification of K, Ca, Ti, Mn, Fe, Zn, Rb, Sr, Sn and Pb in the liquid extracts was proved to be a faster alternative to other more classic quantification techniques (i.e. ICP-MS), accurate enough to obtain information about the composition of the acidic soluble part of the materials and their degradation products. Regarding the solid samples measured as suspensions, it was quite difficult to obtain stable and repetitive suspensions affecting in this way the accuracy of the results. To cope with this problem, correction factors based on the quantitative results obtained using ED-XRF were calculated to improve the accuracy of the TXRF results. [ABSTRACT FROM AUTHOR]

The purpose of the study was performing a round-robin test for the element analysis of mammalian tissue samples using total reflection X-ray fluorescence (TXRF). To achieve this goal, the selected rat organs (kidney, heart, spleen and lung) were subjected to microwave digestion and, in the liquid form, were sent to four European laboratories participating in the inter-comparison investigation. There, using various commercially available TXRF spectrometers, their elemental composition was determined. The carried inter-laboratory comparisons involved macroelements with the concentration above 1000 μg/g (P, S and K) as well as microelements (Ca) and trace elements (Fe, Cu, Zn and Se) occurring, respectively, in the concentrations of 100–1000 μg/g and below 100 μg/g. The validation parameters such as the detection limits of the examined elements as well as the intra-day and inter-day precision were determined. To verify the variation in the results acquired in participating laboratories, for all measured elements, the inter-laboratory precision was evaluated. The data obtained by TXRF were also compared with the ones resulting from ICP-MS (Se) and ICP-OES analysis (P, S, K, Ca, Fe, Cu and Zn). The results obtained as part of the study confirmed the high usefulness of the TXRF method in the elemental analysis of animal tissues. As expected, the best results in terms of the examined validation parameters were obtained for elements with higher atomic numbers (Fe, Cu, Zn and Se). For these analytes, the round-robin test confirmed a good accuracy (around 100% for Fe, Cu, Zn) and precision (intra-day <6%, inter-day <12% and inter-laboratory <12%) what supports the use of TXRF for their determination in the mammalian tissue samples. The obtained results allowed, moreover, to indicate potential issues that require resolving in order to increase the usefulness of the method in case of the analysis of light elements such as P, S or K. It is worth mentioning here, inter alia , the improvement of the sample preparation procedures aiming at the reduction of self-absorption in its dried residue, optimization and/or unification of the sensitivity calibration and the spectra fitting procedures in particular laboratories. [Display omitted] • First round-robin test of the element analysis of rat tissues carried out using TXRF. • Four European laboratories participated in the inter-comparison investigation. • Concentrations of macro-, micro- and trace elements were determined in the samples. • Detection limits of elements, precisions and trueness were evaluated. • Round-robin test confirmed a good accuracy and precisions for Fe, Cu, Zn and Se. [ABSTRACT FROM AUTHOR]

The following paper presents statistical analysis of measurement results close to the detection limit of an analytical technique and being random-left censored data. For such observations the measured value is not known precisely but is restricted by the detection limit. In the paper, the idea of random-left censored observations and data analysis are presented generally and next it is shown how to include censored observations into the statistical analysis with the use of available statistical analysis software (survival analysis procedure). Statistical procedure is presented on the examples of the X-ray spectroscopic analysis of element concentrations in medical and biological samples. Censored observations are included in data analysis and quartiles are estimated. Additionally, two- and multigroup comparison is presented for the censored observations. The accuracy of the presented procedure is demonstrated and discussed on the basis of Monte-Carlo simulations. [Display omitted] • X-ray spectroscopic measurement results limited by detection limit (censored data). • Analysis of censored observations with the use of statistical analysis software. • Analysis based on examples of TXRF measurements in medical and biological samples. • Procedure accuracy demonstrated on the basis of Monte-Carlo simulations. [ABSTRACT FROM AUTHOR]

Exposure to arsenic (As) through drinking water results in accumulation of As and its methylated metabolites in several organs, promoting adverse health effects, particularly potential development of cancer. Arsenic toxicity is a serious global health concern since over 200 million people are chronically exposed worldwide. Abundant biochemical and epidemiological evidence indicates that the kidney is an important site of uptake and accumulation of As, and mitochondrial damage plays a crucial role in arsenic toxicity. However, non-destructive analyses and in situ images revealing As fate in renal cells and tissue are scarce or almost non-existent. In this work, kidney tissue from exposed rats was analyzed by EDXRF (Energy dispersive X-ray fluorescence), micro-SRXRF (micro X-ray Fluorescence using Synchrotron Radiation), SRTXRF (SRXRF in total reflection condition), SEM-EDX (Scanning Electron Microscope in combination with EDXRF) and SRXRF-XANES (SRXRF in combination with X-ray Absorption Near Edge Spectroscopy). Our results provide evidence of renal cortex distribution of As with periglomerular localization, co-localization of S, Cu and As in subcellular compartment of proximal tubule cells, mono-methylarsonous acid accumulation in renal cortex mitochondria, and altered subcellular concentration and distribution of other elements. • The distribution of As in renal tissue was analyzed without pre-treatment. • SRXRF and SEM-EDX allowed corroborate co-location of Cu and As in proximal convoluted tubules. • For the first time, the compartmentation of arsenic in the renal tubules is shown in images. • The most toxic species of As MMAIII, accumulates in mitochondria. • X-ray Fluorescence Spectroscopy provides an accurate and high-resolution picture of As bioaccumulation. [ABSTRACT FROM AUTHOR]

In recent years, the production of silver nanoparticles (AgNPs) has grown due to their antibacterial properties. This fact enhances the release of these particles into the environment, especially in soils that are the major sink. To better understand adsorption processes in soils, usually batch kinetic studies are carried out. In this context, we tested the possibilities of using total reflection X-ray fluorescence spectrometry (TXRF) to monitor the silver content in soil adsorption kinetic studies. It was found that the lower limit of detection for Ag (through Ag-Kα detection) in aqueous solutions was around 37 μg·L − 1 , which was suitable to carry out this kind of studies. Moreover, the direct analysis of Ag adsorbed onto soil after the kinetic studies was investigated. In this case, the limit of detection for Ag was around 1.7 mg·kg − 1 . All TXRF results were compared with those obtained by inductively coupled plasma optic emission spectrometry and good agreement was found. The batch adsorption tests performed showed that 98% of polyvinylpyrrolidone coated AgNPs were retained on the tested soils in < 6 h. [ABSTRACT FROM AUTHOR]

This work investigates the potential of high-resolution continuum source graphite furnace atomic absorption spectrometry for the direct determination of Pd, Pt and Rh in two samples of very different nature. While analysis of active pharmaceutical ingredients is straightforward and it is feasible to minimize matrix effects, to the point that calibration can be carried out against aqueous standard solutions, the analysis of used automobile catalysts is more challenging requiring the addition of a chemical modifier (NH 4 F·HF) to help in releasing the analytes, a more vigorous temperature program and the use of a solid standard (CRM ERM®-EB504) for calibration. However, in both cases it was possible to obtain accurate results and precision values typically better than 10% RSD in a fast and simple way, while only two determinations are needed for the three analytes, since Pt and Rh can be simultaneously monitored in both types of samples. Overall, the methods proposed seem suited for the determination of these analytes in such types of samples, offering a greener and faster alternative that circumvents the traditional problems associated with sample digestion, requiring a small amount of sample only (0.05 mg per replicate for catalysts, and a few milligrams for the pharmaceuticals) and providing sufficient sensitivity to easily comply with regulations. The LODs achieved were 6.5 μg g − 1 (Pd), 8.3 μg g − 1 (Pt) and 9.3 μg g − 1 (Rh) for catalysts, which decreased to 0.08 μg g − 1 (Pd), 0.15 μg g − 1 (Pt) and 0.10 μg g − 1 (Rh) for pharmaceuticals. [ABSTRACT FROM AUTHOR]

Proper supply of nutrients to plants is mandatory for adequate crop production. Many strategies, such as soil fertilization, nutrient foliar spraying, and seed treatment have been proposed to this goal. Currently, plenty of studies in plant nutrition afford only a low mass of sample for analyses, which is not sufficient for most spectroscopic techniques, including conventional energy dispersive X-ray fluorescence spectrometry (EDXRF). In this context, we developed a new EDXRF method for the determination of nutrients in mass-limited soybean plant tissues. Soybean seeds were treated with different types of Zn suppliers (ZnSO 4 and ZnO nanoparticle sources), sowed, and soybean roots and shoots were sampled two weeks after germination. For EDXRF analysis, 20 mg of samples were suspended in 1 mL of deionized water, and 20 μL of the suspension were dried on a 6 μm polypropylene film in an X-ray cup. External calibration using a set of synthetic aqueous cellulose multielemental standards suspended in 1% Triton X-100 proved to be a good strategy for quantification purposes. The trueness of the proposed method was verified analyzing several plant tissue certified reference materials. Additionally, soybean samples were also analyzed by using a validated total reflection X-ray fluorescence (TXRF) method, and good agreement was found between both analytical approaches. To sum up, the proposed EDXRF thin film method is straightforward and reliable for mass limited vegetal sample multielemental analysis and, additionally, follows the green analytical chemistry postulates. Unlabelled Image • Analytical approach for vegetal (20 mg) mass-limited sample analysis by EDXRF. • Quantification by aqueous multielemental STDs with cellulose and 1% Triton X-100. • Appropriate P, S, K, Ca, Mn and Fe LOQ for vegetal tissue analysis by EDXRF. • Good agreement between EDXRF and TXRF results for soybean root and shoot analyses. [ABSTRACT FROM AUTHOR]

The objective of this work was to investigate the potential of energy dispersive X-ray fluorescence spectrometry for polymeric thin film thickness measurements using univariate and multivariate statistical tools. To this end, nine polymeric films 1.5 to 7.6 μm thick with different composition were used for calibration and validation purposes. The univariate approach was not suitable as thickness measurement strategy, because the coefficient of determination (R2) between the Rh-Kα Compton (18.54–19.83 keV) counting rate and the thin film thickness was estimated as 0.873 (n = 9). Even lower R2 values were estimated for other X-ray spectral regions. On the other hand, the multivariate approach proved to be appropriated for the polymeric thin film thickness measurement, presenting satisfactory R2 values (0.993–0.998; n = 8), precision (4%) and recovery (97%). The scanning electron microscopy was employed for validation of the proposed multivariate strategy. One can concluded that we show that the energy dispersive X-ray fluorescence using multivariate approach is a powerful non-destructive tool to measure the polymeric thin film thickness. Unlabelled Image • Polymeric thin film thickness measurement by EDXRF and multivariate analysis • Partial least squares (PLS) regression for the multivariate calibration • Simultaneous thin film contamination assessement • Non destructive and expedite analysis. No consumables for running [ABSTRACT FROM AUTHOR]