Determination of trace elements in aerosol samples by Instrumental Neutron Activation Analysis

Two nuclear techniques, Energy-Dispersive X-Ray Fluorescence Analysis (EDXRF) and Instrumental Neutron Activation Analysis (INAA), were used to analyze aerosol samples collected in the city of São Paulo, Brazil. Na, Cl, Mn, V, Al, Sm, Mo, W, La, As, Br, Sb, K, Ba, Se, Th, Cr, Rb, Ca, Fe, Ce, and Sc were determined by INAA, and Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, As, Se, Br, Rb, Sr, Hg, and Pb were determined by EDXRF. A preliminary identification of the main source of the atmospheric aerosol was performed based on enrichment factor and correlation coefficient calculations.

     

Study of trace element correlations with drought tolerance in different sorghum genotypes using energy-dispersive X-ray fluorescence technique

Drought-tolerant and drought-susceptible genotypes of sorghum (Sorghum bicolor L. Monech) were analyzed by the energy-dispersive X-ray fluorescence (EDXRF) technique to study the correlation of trace elements with drought-tolerance capacities. Samples prepared from mature seeds, young seedlings, and old plants were analyzed using a ¹⁰⁹Cd radioisotope source and a Si(Li) semiconductor detector of resolution 170 eV for 5.9-keV MnK{ie255-1} X-rays. Elements such as K, Fe, Cu, Zn, Rb and Sr and Y were found to be present in varying concentrations in different samples. The trace element profile studied in the seeds of 11 genotypes and in seedlings (young and old) of 4 sorghum genotypes showed considerable variation. The genotype Arfa Gadamak (AG) showed a distinct presence of a high level of Zn in its young seedling. It was observed that in most of the genotypes (seeds), K and Fe concentrations were more in the tolerant genotype as compared to the susceptible type. The concentration of Fe decreased with maturity in the tolerant group and it increased with maturity in the susceptible group.     

Provenance d’artefacts en rhyolite corse : évaluation des méthodes d’analyse géochimique

Through the analysis of flint and obsidian artefacts, numerous studies have shown the links that existed between Corsica and Sardinia during Neolithic and Chalcolithic. However, we have almost no information about the movements and exchanges that took place in Corsica itself. Rhyolite, a siliceous volcanic rock, has been exploited in Corsica and disseminated throughout the territory from the early Neolithic. Up to now, only one major study has been conducted in the North of the island, in order to identify, by petrographic analysis, the raw material deposits of these rhyolite artefacts. Petrography is a destructive method; it is thus difficult to apply it to large series of archaeological objects. Our aim was therefore to investigate less invasive analytical methods, based on the geochemistry of rocks, in order to conduct future studies based on these rhyolite remains. We analysed 34 geological samples from four different sources, as well as 31 archaeological samples unearthed at three different archaeological areas. We show that EDXRF is an effective method to discriminate sources but also to characterise artefacts using nondestructive protocol. LA-ICP-MS encounters issues due to heterogeneity of the studied rocks. However, we show that by adjusting our testing protocol this method can complement the EDXRF analysis, which is ineffective on objects that are too thin.     

Analysis of human tissues using Energy Dispersive X Ray Fluorescence – Dark matrix determination for the application to cancer research

BackgroundX ray Fluorescence has been essayed as a suitable technique for the elemental quantification of trace element in human tissues, namely comparison of normal and cancerous tissue. However, accurate results depend on a robust quantification approach, namely correct evaluation of the samples’ dark matrix.MethodsIn order to determine the most suitable dark matrix composition for the quantification of such samples using the Fundamental Parameter approach, we have measured several Certified Reference Materials and essayed different dark matrix compositions to achieve the most accurate results. The resulting dark matrix was then applied to normal and tumor ovarian and prostate tissue samples, and the obtained results were compared with the ones obtained with a comparative method using external standard calibration curves.ResultsUsing a dark matrix composed of 10 % - H, 22 % - C, 3 % - N and 60 % - O yielded the best compromise in accuracy for the light and heavy elements. For the reduced sample size and conditions of this study, for both organs, the concentrations of transition metals decrease in tumor tissues, while the concentration of lighter elements, P and Cl, increases. On the other hand, there are elements that showed different behavior between the two types of tissue, namely Zn and S, that increase in prostate tumor tissue and decrease in ovarian tissue.ConclusionAn increase in precision was one of the improvements found with the newly developed method, as the FP-approach contemplates matrix effects and the influence of other elements in the analytes’ quantification. Additionally, the determined dark matrix can be employed in any tissue analysis application by means of EDXRF.     

Effects of Bitumen Deposit on Soil Physico-Chemical Characteristics

Soils in the bitumen deposit area of Nigeria were analyzed for the physico-chemical characteristics and element contents to determine the level of contamination by the natural resource and to provide a framework for establishing relationships between the chemistry of mineral deposit and its host soils. The physico-chemical parameters were determined using standard analytical methods, while the elemental concentrations were determined by Energy Dispersive X-ray Fluorescence Spectrometry technique. The results revealed that soils had higher concentrations of associated hydrocarbon formation elements than other Nigerian soils but lower than the sand and bitumen fractions of Nigerian bituminous sands, indicating contamination of the bitumen host soils by the mineral deposit. Strong positive correlations existed between some elements in the soils, suggesting common sources or chemical similarities. Positive correlations are shown by the results of the cross plot analysis, which establish relationships between the soils and the bitumen deposit, indicating that contamination of the soils could easily affect other components of the ecosystem, viz water and vegetation.     

Detection and determination of selenoproteins by nuclear techniques

Microbeam X-ray spectrometry, energy-dispersive X-ray fluorescence analysis, and neutron activation analysis were evaluated for the detection of selenium contained in the selenoprotein glutathione peroxidase. The glutathione peroxidase had been previously separated using polyacrylamide gel electrophoresis. The use of Bragg-reflected polarized X-ray beams was employed in the X-ray fluorescence measurements to minimize the problem of scatter owing to the gel matrix. Current detection limits of selenium in a gel matrix are 2.1 ng in the bench-top microbeam X-ray system and 30–60 ng using XRF with polarized beams. Neutron activation analysis was used for qualitycontrol measurements, with a detection limit here of <0.08 ng. The work has in principle established the feasibility of such an approach.     

An application of EDXRF on the study of barley seedlings growth on sewage sludge

An energy dispersive X-ray fluorescence method for trace element analysis in plants (leaves and roots) is presented. The method is characterized by the use of a secondary target excitation, thin specimen, and microwave acid digestion. The accuracy is about 10% and the sensitivity is in the range 10–50 ng/cm². The analysis time (from dry sample to concentration data) is about 4×10³ s. The effects of Cr in sewage sludge on barley seedling growth is presented.     

Effect of γ-radiation on some elements in certain organs of albino rats

Energy-dispersive X-ray fluorescence (EDXRF) was used to determine the concentrations of Ca, Cl, Fe, Ni, P, K, Se, S, and Zn in heart, lung, liver, spleen, and kidney of adult albino rats 2 mo after they were subject to a single gamma γ-radiation dose from⁶⁰Co at 5 gy. In female rats, K levels were significantly higher and the Ca levels significantly lower for the irradiated animals when compared to age-matched nonirradiated controls. Significant differences between irradiated and nonirradiated tissues were observed for other elements, although no sex-related differences could be found. Tissue damage and disturbances of biological functions were observed as a result of γ-irradiation.     

Direct analysis of human blood (mothers and newborns) by energy dispersive X-ray fluorescence

This work is an application of energy dispersive X-ray fluorescence (EDXRF) as analytical technique for trace element determination in human tissues. Potassium (K), calcium (Ca), iron (Fe), copper (Cu), zinc (Zn), bromine (Br), rubidium (Rb) and lead (Pb) were determined directly in blood samples from 66 mothers at delivery after full-term pregnancies. The corresponding 66 cord-blood samples of the newborns were also analysed, in order to find element correlations between maternal and newborn blood at birth. The studied samples were obtained from mothers aged between 15 and 39 years old, the gestational age being between 35 and 41 weeks and the newborns' weight between 2.310 and 4.310 kg. Samples were lyophilised and analysed without any chemical treatment. Very low levels of Pb were found both in maternal and fetal cord blood samples. Cu values ranged from 3 to 13 microg g-1, both for mothers and children. A correlation between Cu and Fe concentrations in maternal and fetal cord blood was found. Zn is considered as one of the key elements in newborn health. Concentrations between 10 and 40 microg g-1 were measured. A positive correlation between Br levels in mothers and children was observed. Positive correlations for mothers were observed between Zn and Rb as well as K and Fe. The corresponding correlations in fetal cord blood samples were not observed, however positive correlations were found between Ca and K; Cu and Fe. The mean concentrations for each element were similar in maternal and in fetal cord blood, except for Cu and Zn, being higher in maternal samples. No correlations between element concentrations and pathologies of the mothers were observed.     

Bulk and trace element analysis of spices: the applicability of k0-standardization and energy dispersive X-ray fluorescence

Methodology has been developed for the bulk and trace element analysis of spices such as curry powder and turmeric powder originated from Sri Lanka by the k₀-standardization method (INAA-k₀) and by energy dispersive X-ray fluorescence (EDXRF). SRM 1572 citrus leaves was used to check the accuracy of the results obtained by the two nuclear techniques. The elements determined quantitatively in these matrices by the EDXRF analysis were bromine, calcium, copper, iron, potassium, magnesium, manganese, phosphorus, rubidium, sulphur, strontium and zinc. The results obtained by the two techniques are comparable, although a few inconsistencies were detected, requiring adequate attention for their correction, whenever possible, in future studies.