José Paulo Santos

Material, Culture, Scientific Culture: Industrial Heritage for the Future

In this work, we present a novel application of the full-field energy-dispersive X-ray fluorescence (EDXRF) imaging system based on a MicroPattern Gaseous Detector (2D-THCOBRA) in the cultural heritage field. The detector has an intrinsic imaging capability with spatial resolution of 400μmFWHM, and is energy sensitive, presenting an energy resolution of approximately 1keVFWHM at 5.9keV. The full-field XRF scanner based on the 2D-THCOBRA detector allows mapping the distribution of elements in large area samples with high detection efficiency (75 % at 5.9keV), being a very promising choice for elemental mapping analysis of large area cultural heritage samples. In this work, we have demonstrated the imaging capabilities of the full-field XRF scanner and used it to assess the restoration of a Portuguese faience piece.

In this work, we aim at achieving the most accurate quantitative determination of elements in human tissues by means of X-ray Fluorescence spectrometry using the external calibration approach. A calibration curve built using a set of certified reference materials (CRM) of animal tissue was compared with the one obtained with a set of CRMs of plants and leaves with lower atomic number Z but with correction of the matrix using the scattering peaks of the X-ray tube anode. Finally, a calibration curve combining the two sets of CRMs was built and the accuracy of the quantification using the three methods was compared and a more precise method of quantification was obtained. This improved approach was tested on five paired samples of normal and tumour human tissue. Despite the high heterogeneity of the samples, and given the improvement in accuracy of the measurements, significant differences were found in the elemental concentration of low-Z elements. This journal is

The aim of this study is to evaluate the elemental composition of six food supplements of plant origin, commonly sold in the Portuguese market, by energy dispersive X-ray fluorescence. The presence of arsenic in all the Maca, Ashwagandha, Camu-Camu and Hemp protein samples (except the generic form) is a reason of concern due to the long-term effects of As mainly in its inorganic form. Thus, great caution must be taken on some food supplements, particularly the cases of Moringa from Egypt and Yellow/Xpresso Maca, whose inorganic As concentrations are in line with the upper bound concentration for the 95th dietary exposure according to the European Food Safety Authority which is 0.64 μg/kg bw/day. In what regards Hemp protein, if the supplier’s daily intake recommendation (30 g) is followed, values as high as 1.75 μg/kg bw/day of inorganic As will be consumed, which are dangerously above the upper bound. In this case this specific supplement lot should be removed from the market. Also the consumption of Hemp protein leads to a daily intake of Mn above the Daily Reference Intake (DRI) and Adequate Intakes (AIs) for adults. The contamination of Goji berries by Pb is a reason for concern—organic berries contained 11.3 μg/g while berries derived from conventional agriculture 11.6 μg/g, leading to daily intake doses of 315.3 μg and 324.8 μg, respectively, if the recommended daily intake of 28 g is followed. Our findings point out to an inadequacy of the recommended intakes by the supplier vis a vis the concentrations observed, greatly increasing the risk for public health.

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We report on measurements of the Kβ diagram, valence-to-core (VtC), and hypersatellite X-ray spectra induced in metallic Cr by photon single and double K-shell ionization. The experiment was carried out at the Stanford Synchrotron Radiation Lightsource using the seven-crystal Johann-type hard X-ray spectrometer of the beamline 6-2. For the Kβ diagram and VtC transitions, the present study confirms the line shape features observed in previous works, whereas the K h β hypersatellite transition was found to exhibit a complex spectral line shape and a characteristic low-energy shoulder. The energy shift of the hypersatellite relative to the parent diagram line was deduced from the measurements and compared with the result of extensive multiconfiguration Dirac–Fock (MCDF) calculations. A very good agreement between experiment and theory was found. The MCDF calculations were also used to compute the theoretical line shape of the hypersatellite. A satisfactory agreement was obtained between the overall shapes of the experimental and theoretical spectra, but deviations were observed on the low- and high-energy flanks of the hypersatellite line. The discrepancies were explained by chemical effects, which were not considered in the MCDF calculations performed for isolated atoms.

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Spectrochimica Acta Part B: Atomic Spectroscopy, 130 (2017) 35-38. doi:10.1016/j.sab.2017.02.006

In this paper, we study the performance of a portable energy dispersive X‐ray fluorescence spectrometer by making use of different filter configurations at the X‐ray tube output. To fulfill this purpose,...

Spectrochimica Acta Part B: Atomic Spectroscopy, 129 (2016) 1-7. doi:10.1016/j.sab.2016.12.006

Spectrochimica Acta Part B: Atomic Spectroscopy, 130 (2017) 60-66. doi:10.1016/j.sab.2017.02.012

In this study, we investigate the capability of energy dispersive X-ray fluorescence (EDXF) spectrometry in a triaxial geometry apparatus as a fast and nondestructive determination method of both dominant and contaminant elements in pharmaceutical iron supplements. The following iron supplements brands with their respective active ingredients were analyzed: Neutrofer fólico (iron gylcinate), Anemifer (iron(II) sulfate monohydrate), Noripurum (iron(III)-hydroxide polymaltose complex), Sulferbel (iron(II) sulfate monohydrate), and Combiron Fólico (carbonyl iron). Although we observe a good agreement between the iron content obtained by the present method and that indicated in the supplement's prescribed dose, we observe contamination by manganese and nickel of up to 180 μg and 36 μg, respectively. These contents correspond to 7.2% and 14.4% of the permitted daily exposure of manganese and nickel, respectively, for an average adult individual as determined by the European Medicine Agency (EMEA). The method was successfully validated against the concentrations of several certified reference materials of biological light matrices with similar concentrations of contaminants. Moreover, we also validated our method by comparing the concentrations with those obtained with the inductively coupled plasma-atomic emission technique.