1,720,968 research outputs found
Multi-element analysis of vegetal foodstuff by means of low power total reflection X-ray fluorescence (TXRF) spectrometry
No full textIn 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
Determination of trace elements in Italian wines by means of total reflection X-ray fluorescence spectroscopy
No full textAnalytical performance of benchtop total reflection X-ray fluorescence instrumentation for multielemental analysis of wine samples
No full textRecent 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 waterThisworkwas supported by the Spanish National Research Program (Project ref. CGL2013-48802-C3-2-R
Chemical Stabilization of Municipal Solid Waste Incineration Fly Ash without Any Commercial Chemicals: First Pilot-Plant Scaling Up
No full textFor the first time in Europe, results of chemical stabilization of municipal solid waste incineration (MSWI) fly ash, realized as a pilot plant, are reported. The stabilization technology is based on the use of only waste and byproduct materials (such as coal fly ash, flue gas desulfurization residues, and rice husk ash). In the frame of the COSMOS-RICE project, a pilot plant was built in Italy, with a capacity of more than 0.5 tons of MSWI fly ash/day. The stability of the material obtained was investigated by the evaluation of the pH dependency of the leaching of metals, 6 months after the treatment. The pH dependence of heavy metal solubility was described in terms of unified leaching curves, comparing first-time leaching data of MSWI fly ash from different geographical locations (Italy, Portugal, Denmark, and China), using a polynomial function. Results confirmed that COSMOS-RICE technology can be a promising path for obtaining a stabilized product with likely practical applications, avoiding costly and unsustainable landfilling
Elemental analysis of tree leaves by total reflection X-ray fluorescence: New approaches for air quality monitoring
No full textEvaluation of different quantification modes for a simple and reliable determination of Pb, Zn and Cd in soil suspensions by total reflection X-ray fluorescence spectrometry
No full textIn view of the large number of soil analyses in environmental studies dealing with metal contamination, the
use of simple, fast, sustainable and cost-effective methodologies is desired. In this sense, the role of total
reflection X-ray fluorescence spectrometry (TXRF) has to be highlighted due to the possibility of direct
analysis of solid suspensions without the need for a digestion process. Internal standardization is
successfully used as a quantification approach in multielement TXRF analysis of liquid samples, including
soil digests. However, its application for the analysis of soil suspensions is not always possible. In the
present manuscript we found that although acceptable results were obtained for TXRF quantification by
internal standardization when considering soil certified reference materials (recoveries: 80–120%),
a systematic underestimation of the concentration values was found when using the same approach for
real soil sample analysis (recoveries <70%). In view of these problems, we explored the possibilities of
different quantification approaches, including external calibration, which can be used in combination
with soil suspension preparation and TXRF analysis to obtain reliable results for metal determination in
soils. Data obtained showed that the best strategy was the use of internal standardization with correction
of the TXRF results using a calibration curve obtained in the analysis of a set of soil samples with a matrix
similar to the unknown ones by using a reference technique (digestion and ICP-OES analysis). With this
analytical approach quantitative results were obtained for all the studied metals with recovery values
around 95%. As a study case, the proposed TXRF method has been applied for the specific determination
of Pb, Zn and Cd concentrations in soils from an abandoned metal mining area but the developed
methodology could be extended to other environmental studies dealing with the determination of other
metals and soil types. Taking into account the selectivity and sensitivity limitations when determining
high Z elements such as Cd using TXRF systems equipped with Mo X-ray tubes, we compare the
analytical performance of TXRF systems with different sources (Mo and W) as well
Comparison between rice husk ash grown in different regions for stabilizing fly ash from a solid waste incinerator
No full textThe Stabilization of heavy metals from municipal solid waste incineration (MSWI) fly ash by rice husk ash (RHA) is under intense study as an effective strategy to recover and reuse industrial and agricultural waste together. We compare the metal entrapment performances of RHA from different Asian rice sources – namely from Japonica rice grown in Italy and Indica rice grown in India – Physicochemical and morphological characterization of the final stabilized material show that the same thermal treatment may result in marked structural differences in the silica contained in the two RHA. Remarkably, one of them displays a crystalline silica content, although obtained by a thermal treatment below 800 °C. We also find that the presence of an alkali metal ion (potassium) in the rice husk plays a crucial role in the attainment of the final silica phase. These physicochemical differences are mirrored by different stabilization yields by the two RHA
Study of metal release from stainless steels in simulated food contact by means of total reflection X-ray fluorescence
Full text linkThis study shows a reliable procedure to prescribe the preferential use of a material for food contact. Release tests with optimized parameters were performed on six different stainless steel accepted for the use in food contact: AISI 420, AISI 430, AISI 202, AISI 303, AISI 304, and AISI 316. Total reflection X-ray fluorescence spectroscopy was used to measure the concentration of Cr, Mn and Ni in contact solutions from release tests. Results show that AISI 202 and 430 release the lowest amount of Mn, Cr and Ni. While, AISI 420 is the worst material, exceeding the limit set in the Italian regulation for all the three metals of interest. One sample was selected to test the reproducibility of TXRF measurements performed in three different laboratories around the world. Results show that quantitative analyses by means of TXRF satisfy the requirements of this field of application
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