A simple method for glass analysis using total reflection X-ray fluorescence spectrometry.

In this work, a simple and cost-effective method was developed for Na, Mg, Al, K, Ca, Ti, V, Cr, Mn, Ni, Cu, Zn, Rb, Sr, Ba and Pb determination in glass samples employing suspension sampling and total reflection X-ray fluorescence (TXRF). The experimental conditions were optimized using multivariate approach being the optimum conditions located by Derringer's desirability function. Proposed method was validated in accordance with the National Institute of Metrology, Quality and Technology (Inmetro, Brazil). Limit of detection (LD) and limit of quantification (LQ) were adequate for determination of trace elements in glass. The evaluation of the accuracy and precision was realized by analysis of standard reference materials of glass (NIST 612). For the majority of the elements, good agreement was achieved between the certified value and the value obtained in the NIST 612. The relative standard deviation (RSD%) was achieved between 3.6 and 10.3%. Moreover, no significant differences were observed between the proposed method compared to the ICP-MS. After the validation step, the method was applied to 31 glass samples and with aid of an exploratory principal component analysis (PCA), a perfect discrimination of the glass from originally manufactured smartphones was obtained. In addition, soda-lime glass could be reasonably distinguished from smartphone screens. The developed method is fast, consumes low amounts of reagents and allows the determination of many analytes simultaneously. Additionally, the method does not require calibration curves. Therefore, TXRF proved to be attractive and useful for routine analysis of glass.

Study of inorganic elements in different organs and tissues of Amazonian manatee (Trichechus inunguis) from Brazil.

Multielement concentrations (P, S, Cl, K, Ca, Cr, Mn, Fe, Ni, Cu, Zn, Rb, and Rh) and total mercury (T-Hg) were analyzed in different organs and tissues of Amazonian manatee (Trichechus inunguis). Samples of 27 T. inunguis specimens, maintained in the collection of the Amazonian Center for the Research and Preservation of Aquatic Mammals, were used, situated in an area highly impacted by gold mining in the northern region of the Brazilian Amazon. Samples of aquatic plants used as food by the animals were also analyzed. The elements S, Cl, K, Cr, and Mn accumulated mainly in the musculature, while Fe and Cu were more concentrated in the liver. Trace elements, such as rubidium (Rb) and rhodium (Rh), not previously reported in the organs of animals of the family Trichechidae, were also identified. The averages for T-Hg in the skin, muscle, encephalon, liver, kidney, and lung samples were, respectively, 0.1540 ± 0.1332, 0.0593 ± 0.1044, 0.0517 ± 0.0467, 0.0486 ± 0.0543, 0.0237 ± 0.0336, and 0.0013 ± 0.0032 µg.g-1. The values obtained for the vibrissae samples were below the limit of quantification, which allows for the conclusion that this tissue cannot be used as a contamination marker. It was observed that even when kept in a conservation breeding site, these animals were exposed to non-essential trace elements. Differences in the accumulation of elements were observed between the different organs and tissues analyzed. The presence of contaminants in animals that live in a preservation center, even at low levels, deserves attention.

Circulating Concentration of Chemical Elements During Exercise-Induced Muscle Damage and the Repeated Bout Effect.

The objective of the study was to evaluate the circulating levels of chemical elements after exercise-induced muscle damage (EIMD) followed by the repeated bout effect (RBE). Seven physically active subjects (26.5 ± 4.0 years) performed two sessions of EIMD (5 sets of 20 drop jumps), the second session 14 days after the first for RBE assessment. Blood collections, countermovement jump (CMJ), squat jump (SJ), and delayed-onset muscle soreness (DOMS) were performed before (Pre), after (Post), and 24, 48, and 72 h after the exercise session. Creatine kinase (CK) was detected by biochemical analysis and the concentration of chemical elements by total reflection X-ray fluorescence (TXRF). Differences between time points and sessions were assessed with two-way ANOVA and the effect size (ES). EIMD induced a reduction in the CMJ at 24 h (P < 0.05) and an increase in DOMS at 24 h (P < 0.01) and 48 h (P < 0.01), and CK at 72 h (P < 0.05). RBE alleviated all symptoms of EIMD in the second session (P > 0.05). EIMD induced a large to very large ES for Zn reduction at 24 h (- 1.37) and 72 h (- 0.93) and Br (- 0.83) at 72 h. RBE presented large to very large ES for the increase in P at 48 h (0.92); Cl at 24 h (1.04); K at 24 h (0.91), 48 h (1.10), and 72 h (0.96); Ca at 72 h (0.92); and Fe at 24 h (0.85). RBE influenced the concentration of elements associated with fatigue (K, Ca, Cl), inflammatory response, and glucose metabolism (Zn).

Application of total X-Ray fluorescence to gunshot residue determination.

Currently the great majority of the criminal acts have involved the use of firearms, for these reasons the evidences generate from these are one of the fundamental pillars of a forensic investigation. The firearm leaves evidence known as gunshot residue (GSR), which is principally composed of burnt and unburnt particles from the detonation, as well as fragments of the bullet, cartridge case, and the firearm. Gunshot residue (GSR) is produced when a firearm is discharged and large quantities of it can be transferred to an individual who has fired. SEM-EDX is the common technique used in the forensic laboratories, the analysis consists in detecting the particles and its elements. In this work we propose the use of X-ray Spectrometry by Total Reflection (TXRF) for the analysis of metals present in related samples in ballistic cases. The analysis was focused in the relationship of three elements present in GSR. A series of experiments with different persons firing gun of 9 mm was performed in a shooting range. Analytical XRFS signals corresponding to K line of Copper and L lines Barium and Lead were employed as the best discriminating variables. Machine Learning techniques, such as discriminant analysis, supported vector machines and partial least squares - discriminant analysis, enable the correct classification of all samples analyzed. A hundred samples were analyzed so far, this method has demonstrated a very high classification performance for detecting gunpowder residues in the skin.

Chromium and Lead adsorption by avocado seed biomass study through the use of Total Reflection X-Ray Fluorescence analysis.

Adsorption is an effective method for the treatment of wastewater containing low concentrations of heavy metals. This kind of metals such as Chromium and Lead could affect health and the ecosystem. In this work, biomass of avocado seed was used as adsorbent. It was tested as adsorbent in natural form (NB), as a chemically activated (AB) form and as activated carbon (AC). Batch reactors were used to investigate the adsorbent efficiency. Concentration of metal ions was measured using Total Reflection X-Ray Fluorescence. Operational conditions influencing adsorption, such as: pH, adsorbent dose, initial concentration and contact time, were measured and controlled. The 80% of adsorption was reached, at pH: 5 and 25 °C, when were used 50 mL of: a 20 mg L-1 of Cr (VI) solution with a dose of 1.25 g of NB, a 30 mg L-1 of Pb (II) solution with a dose of 0.15 g of NB, a 50 mg L-1 Pb (II) solution with a dose of 0.15 g of AB, a 30 mg L-1 Cr (VI) solution with a dose of 0.35 g of AB, a 30 mg L-1 of both metals, with a dose of 0.15 g of AC for Pb (II) and 0.7 g of AC for Cr (VI). In all cases, the pH value before and during the experiments remained constant, indicating the lack of acid/base reactions during the processes. The Langmuir adsorption isotherm model best fitted to the experimental data. The experimental results from kinetic studies best correlated using the pseudo-second order model. An increase in the remotion of both ions (Pb (II) and Cr (VI)), was observed when comparing the results obtained using the activated biomass. However, considering the loss of biomass that the pre-treatment causes, the remotion per gram of initial biomass does not vary significantly.

Multielemental composition and consumption risk characterization of three commercial marine fish species.

Marine fish are considered a source of high quality proteins and fatty acids. However, the consumption of fish may pose a health risk as it may have potentially toxic elements in high concentrations. In this study we quantify the multielemental composition of muscle and fins for three species of commercial marine fish from Brazil: Sphyraena guachancho (Barracuda), Priacantus arenatus (Common bigeye) and Genidens genidens (Guri sea catfish). We then assessed the potential risk of fish consumption by means of a Provisional Hazard Indices. Amongst the elements detected in fish tissue were potentially toxic elements such as Ag, Ba, Cd, Cr and Hg. Concentration differences were species-specific, and affected by the species trophic level, morphological characteristics and feeding habits. Results suggest the higher the trophic level of the fish, the higher the risk of consumption. Caution is recommended for the frequent ingestion of high trophic level fish species in Brazil.

Macro-elements in the hemolymph of adult Euschistus heros (Fabr.) (Hemiptera: Pentatomidae) treated with pyriproxyfen.

Euschistus heros is an important pest in many crops in Brazil, and different control strategies, mainly involving chemicals, have been evaluated; however, the side effects of these chemicals on the balance of inorganic element levels in the hemolymph are unknown. Thus, the aim of this work was to determine the concentration of inorganic elements (focusing on macro-elements) in the hemolymph of female and male E. heros adults, after applying pyriproxyfen at a sublethal concentration (LC30 = 6.68 mL L-1 diluted in distilled water) to 4th instar nymphs, which were kept in controlled conditions. The hemolymph pool was removed 48 h after adult emergence, centrifuged and placed on an acrylic disk added with Gallium as internal standard for the analysis of total reflection X-ray fluorescence. Most of the elements in the control treatment did not differ between females and males. However, following insecticide application to females and males, respectively, there was a significant increase in sulfur (19 and 51%), chlorine (33 and 137%) and calcium (47 and 82%) in the hemolymph. The significantly higher increase in macro-elements in males' hemolymph indicates that the action of pyriproxyfen may be sex-specific. Phosphorus and potassium concentrations also differed between females and males in the control and treated groups. The observed variation in inorganic elements in the insect's hemolymph may be related to the unknown effects of pyriproxyfen, mainly on immune and reproductive performance.

A simple method for the multi-elemental analysis of beer using total reflection X-ray fluorescence.

A method of direct analysis for quantification of 15 inorganic elements (P, S, Cl, K, Ca, Mn, Fe, Ni, Cu, Zn, Br, As, Rb, Sr and Pb) in beers by Total Reflection X-Ray Fluorescence (TXRF) was developed. The experimental conditions were optimized. Direct analysis was compared with the acid digestion procedure to evaluate the effect matrix and the results were satisfactory. The evaluation of the accuracy and precision was realized by analysis of two certified reference materials of natural and waste water. For the majority of the elements, good agreement was achieved between the certified value and the value measured in the CRM´s. Low detection limits were obtained and it was adequate to determine trace elements in beers and to quality control Pb and As, whose maximum limits are 200 and 100µgL-1, respectively. The relative standard deviation (RSD%) ranged from 2.4% to 10%. The method was applied to 30 beer samples collected in several regions of Brazil. The concentration ranges (mgL-1) for the studied analytes were: P: (37.40-140.85); S (10.32-50.73); Cl (82.74-281.7); K (183.8-418.5); Ca (9.82-96.0); Mn (0.06-1.42); Fe (0.07-1.57); Ni (< LLD-1.13); Cu (< LLD-0.32); Zn (0.02-1.98); As (< LLD-0.10); Br (0.01-2.04); Rb (< LLD-0.52); Sr (< LLD-0.41) and Pb (< LLD-0.18). Some beer samples showed As and Pb concentrations above the levels established by Brazilian legislation. The developed method is simple, fast, consumes low amounts of reagents and allows the determination of a large number of analytes simultaneously. TXRF proved to be attractive and useful for routine analysis.

A simple method for the multi-elemental analysis of organic fertilizer by slurry sampling and total reflection X-ray fluorescence.

A simple and fast method for the multi-elemental determination of 18 inorganic constituents (P, S, Cl, K, Ca, Ti, Cr, V, Mn, Fe, Ni, Cu, Zn, Br, Rb, Sr, Ba and Pb) in organic fertilizers employing slurry sampling and total reflection X-ray fluorescence (TXRF) is presented. A 2(3) factorial design with a central point was employed to optimize the slurry sampling procedure. The internal standard and instrumental conditions were optimized by univariate studies. The selectivity of the method to determining Se, As, Pb, Cr, Ni and Cd was assessed. The accuracy was evaluated by the analysis of four standard reference materials (SRM). The recoveries varied from 72% to 114%. For most of the elements, good agreement was achieved between the certified value and the value measured in the SRM. The relative standard deviation (RSD %) ranged from 0.5% to 14%. The evaluated method was applied to the determination of analytes in the press cake of palm, castor, curcas, sunflower, fodder turnip, white lupin, rapeseed and pequi, and their potential to be used as organic fertilizer was evaluated in accordance with Brazilian legislation.

Phosphorus migration analysis using synchrotron radiation in soil treated with Brazilian granular fertilizers.

The aim of this study was to evaluate the phosphorus (P) mobility in a tropical Brazilian soil type red Oxisol treated with three different forms of granular fertilizer. Total Reflection X-Ray Fluorescence (TXRF) was applied to determine the concentration of P at different distances from granular fertilizer application point. The results showed that most of the P from fertilizers tends to concentrate in a region of up to 10mm around the place of the fertilizer deposition.

Determination of trace elements in honey from different regions in Rio de Janeiro State (Brazil) by total reflection X-ray fluorescence.

Trace and minor elements in Brazilian honey were analyzed by total reflection X-ray fluorescence spectroscopy. Up to 12 elements (K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Se, Br, and Sr) were detected in 160 samples of honey from 4 regions of Rio de Janeiro State (Barra Mansa, Teresópolis, northern and southern Nova Friburgo). The results showed the samples from Teresópolis had higher rates of essential and nonessential elements than samples from the other regions, except for Ni. K and Ca were the most abundant elements in all samples, in the range of 116.5 to 987.0 µg g(-1) . Ni, Cu, Zn, Se, and Sr were identified in small concentrations (0.01 to 12.08 µg g(-1) ) in all samples, indicating a low level of contamination in all the regions.