Search Results (55)

Apatite is a key indicator mineral whose chemical signature can reveal the genesis and evolution of ore-forming systems. However, correctly interpreting these signatures requires a robust discrimination between apatite types formed by different geological processes, such as metamorphism and hydrothermal activity. This study aims to chemically characterize and genetically classify apatite samples from the Slyudyanka deposit (Siberia, Russia) to establish discriminative geochemical fingerprints for metamorphic and hydrothermal apatite types. We analyzed 80 samples of apatite using total reflection X-ray fluorescence (TXRF) and inductively coupled plasma mass spectrometry (ICP-MS). The geochemical data were processed using principal component analysis (PCA) and k-means cluster analysis to objectively discriminate the apatite types. Our analysis reveals three distinct geochemical groups. Metamorphic veinlet apatite is defined by high U and Pb, low REE, Sr, and Th, and suprachondritic Y/Ho ratios. Massive metamorphic apatite from silicate–carbonate rocks shows extreme REE enrichment and chondritic Y/Ho ratios. Hydrothermal–metasomatic apatite features high Sr, Th, and As, with intermediate REE concentrations and chondritic Y/Ho ratios. Furthermore, we validated the critical and anomalous Y concentrations in the metamorphic veinlet apatite by cross-referencing TXRF and ICP-MS data, confirming the reliability of our measurements for this monoisotopic element. We successfully established diagnostic geochemical fingerprints that distinguish apatite formed in different geological environments at Slyudyanka. The anomalous Y/Ho ratio in metamorphic veinlet apatite serves as a key discriminant and provides insight into specific fractionation processes that occurred during the formation of phosphorites in oceanic environments, which later transformed to apatites during high-grade metamorphism without a change in the Y/Ho ratio. This work underscores the importance of multi-method analytical validation for accurate geochemical classification. Full article

This study examined the characteristics of essential oils and ethanolic extracts from nine pepper species’ fruits to determine their chemical compositions and assess their biological activity. Ethanolic extracts and essential oils were analyzed using HPLC, GC-MS, FTIR, and ¹H NMR spectroscopy. The total phenolic content, total flavonoid content, antioxidant activity (DPPH assay), and antibacterial efficacy against five bacterial strains were assessed. Additionally, multielement analysis was performed using the TXRF method. The results demonstrated that the yields and chemical compositions differed markedly according to the pepper origin and extraction method. Ethanolic extracts consistently demonstrated greater total phenolic content and total flavonoid content and enhanced antioxidant and antibacterial properties relative to their respective essential oils. The increased bioactivity is due to the presence of non-volatile, polar compounds, which are not effectively transferred via hydrodistillation. Piperine was solely detected in extracts from black, green, white, Bengali, and Voatsiperifery peppers. This study emphasizes the necessity of optimizing extraction techniques to enhance the bioactivity of pepper extracts, highlighting their potential as sources of natural antioxidants and antibacterial agents. Full article

This study used Total X-ray Fluorescence Spectrometry (TXRF) to analyze toxic heavy metals, specifically lead (Pb), arsenic (As), and chromium (Cr), in 45 dietary supplement samples consumed by the Mexican population. A health risk assessment was performed using the Target Hazard Quotient (THQ), Hazard Index (HI), and Cumulative Cancer Risk (CCR). The mean concentrations of Pb, Cr, and As were found to be 1.99 ± 0.13, 26.88 ± 0.23, and 2.39 ± 0.11 mg/kg, respectively. For Pb, 80% of dietary supplements showed low EDIs compared to the reference value of 1.08 × 10⁻⁴ mg/Kg bw/day set by the FDA. For Cr, 100% of the analyzed products had EDIs below the limit of 0.3 mg/Kg bw/day established by EFSA. Additionally, some dietary supplements of animal origin had EDIs exceeding the reference value of 6 × 10⁻⁵ mg/kg bw/day set by the Integrated Risk System and EFSA for daily arsenic intake. When evaluating the variables THQ_Pb, THQ_Cr, and THQ_As using mean comparison tests to determine whether they exceeded the reference value of 1, we found that, in general, the available statistical evidence is insufficient (p > 0.05) to conclusively state that the dietary supplements under review surpass this reference parameter. Regarding HI values, the Animal and Vegetable category showed higher values than 1. All dietary supplements had CCR values in ranges greater than 1 × 10⁻⁴, indicating a probability of an individual developing cancer over their lifetime due to metal exposure. Effectively communicating these risks to consumers is crucial for promoting informed choices and improving public health. Full article

The primary source of drinking water for the people of Tonosí, Panama, is groundwater. This research evaluates the presence of heavy metals and possible hazards by combining geochemical and isotopic analyses. Total Reflection X-ray Fluorescence (TXRF) was used to measure metal levels in water and soil near wells and springs, while stable isotope ratios (δ²H and δ¹⁸O) identified the source of groundwater recharge. Isotopic signatures closely aligned with the Local Meteoric Water Line (LMWL), suggesting meteoric origin and limited evaporation. An analysis of Enrichment Factor (EF) for soil samples, utilizing background values from Coiba and Montijo, showed moderate to substantial enrichment of arsenic, chromium, and copper. Soil enrichment suggests possible dangers with environmental shifts like changes in land use or heavy rainfall. These findings highlight the necessity for continual groundwater observation in rural areas and show the benefits of integrating isotopic and geochemical methods to detect sources of contamination and guide protection strategies. This research improves comprehension of heavy metal exposure in tropical aquifers and offers evidence to aid environmental and public health policymaking. Full article

The selection of plant-based substrates for mushroom cultivation is a key factor influencing their growth and metabolism. The aim of this study was to demonstrate, in an innovative approach, differences in the content of biologically active compounds, bioelements, and antioxidant properties of Hericium erinaceus (Bull.) Pers. cultivated on various plant-based substrates derived from waste materials, specifically hemp straw and beech sawdust. Another objective was to compare various extraction methods in terms of their impact on the concentration of these compounds. Elemental analysis was performed using the TXRF method, while bioactive constituents were determined using the DAD/UV RP-HPLC technique. The plant-based substrate and extraction method influenced the levels of obtained metabolites. Dual extraction with moderate ethanol concentrations was most effective for isolating key bioactive compounds from H. erinaceus—notably ergothioneine, lovastatin, L-phenylalanine, and ergosterol—while antioxidant activity did not correlate with the concentration of the solvent used. Although dual extracts enhanced certain antioxidants and metabolites, whole fruiting bodies contained higher levels of bioelements. Overall, fruiting bodies grown on beech sawdust had greater amounts of most bioactive compounds compared to those cultivated on hemp straw, emphasizing that both substrate choice and extraction method critically influence the mushroom’s bioactive profile and its potential health benefits. Full article

This study investigates silver (Ag), copper oxide (CuO), and bimetallic Ag/CuO nanoparticles (NPs) synthesized using Cistus creticus L. extract, focusing on their synthesis, physicochemical characteristics, and antioxidant activity. Green synthesis methods utilizing plant extracts offer environmentally benign routes for nanoparticle fabrication, attracting significant interest across multiple fields. NP formation was confirmed by UV/Vis and total X-ray fluorescence (TXRF) spectroscopy, while dynamic and electrophoretic light scattering (DLS, ELS) characterized particle size and ζ-potential, respectively. AgNPs exhibited the smallest particle size (30.8 ± 8.81 nm), while CuONPs had the largest (44.07 ± 19.19 nm). For Ag/CuONPs, the ζ-potential value was −77.9 ± 2.99 mV. Morphological and structural analyses performed using transmission electron microscopy (TEM), selected area electron diffraction (SAED), and X-ray diffraction (XRD) revealed that AgNPs were spherical, while CuONPs and Ag/CuONPs exhibited spherical and polymorphic structures. Colloidal stability studies over 60 days demonstrated that the NPs were highly stable, indicating their suitability for pharmaceutical and cosmetic applications. Antioxidant activity, assessed via the DPPH assay, demonstrated that CuONPs had the highest free radical scavenging activity. By systemically comparing Ag, CuO, and bimetallic Ag/CuONPs synthesized from Cistus creticus L. extract, this study provides valuable insights for the development of tailored nanomaterials with diverse applications in pharmaceutics and cosmetics. Full article

A biochar (BC) generated by the pyrogasification of wood chips from authorized forestry cuts was extensively characterized and evaluated for its efficacy in retaining/releasing two agrochemicals, namely the fungicide penconazole (PEN), the herbicide S-metolachlor (S-MET), and the xenoestrogen bisphenol A (BPA) widely present in industrial effluents. The elemental composition of BC was evaluated using CN elemental analysis and total reflection X-ray fluorescence (TXRF) spectroscopy which showed the abundance of elements typically found in BCs (Ca, K, P) along with essential trace elements such as Fe and Mn. Scanning electron microscopy coupled with energy-dispersive X-ray analysis (SEM-EDX) described the surface features of BC along with the major surface elements, while Brunauer–Emmett–Teller (BET) analysis revealed, as expected, a large specific surface area (366 m² g⁻¹). High porosity (0.07 cm³ g⁻¹) was demonstrated by the density functional theory (DFT) method, while Fourier transform infrared (FT-IR) spectroscopy highlighted the presence of a prominent aromatic structure and the abundance of reactive functional groups responsible for the binding of the compounds. The sorption/desorption capacity of BC was studied by means of sorption kinetics and isotherms in batch trials, and by modeling the experimental data with various theoretical equations. All compounds reached sorption equilibrium on BC very rapidly, following preferentially pseudo-second-order kinetics. Freundlich adsorption constants of PEN, S-MET, and BPA were 37.3, 13.2, and 11.6 L g⁻¹, respectively, thus demonstrating the great affinity of BC for hydrophobic pollutants. The adsorption process was hysteretic as only a small fraction of each compound was slowly desorbed from BC. The overall results obtained highlighted the great potential of BC of acting as a biosorbent of contaminants, which is of great importance for the containment of pollution in agricultural soils and for limiting the entry of toxic compounds into the human and animal food chain. Full article

This paper briefly overviews the application of total-reflection X-ray fluorescence (TXRF) spectrometry in the biosciences, focusing on key bioanalytical applications. It seeks to review and update the current state of TXRF’s use in biomedical, biochemical, and pharmacological research. The review highlights relevant works in the field, summarising past achievements and incorporating the latest developments. The goal is to demonstrate how the analytical application of TXRF spectrometry in this area has evolved and what its role is in analysing trace elements and other biomolecules in diverse biological samples and diseases. Physical foundations to understand its analytical power and its comparison with related analytical techniques are presented to gain objective knowledge of the benefits, limitations, and drawbacks that TXRF spectrometry can offer. Full article

Brazilian stingless bee species produce honey with distinct physicochemical and bioactive properties shaped by environmental factors. This study investigated the effects of the rainy and dry seasons on the physicochemical characteristics, chemical fingerprinting, mineral content, and antioxidant capacity of honey from Melipona mondury and Melipona bicolor. The honey samples were analyzed for their phytochemical properties (official methods), total phenolics (Folin–Ciocalteu method), flavonoid content (aluminum complex formation method), antioxidant capacity (FRAP and ABTS assays), and antioxidant activity (erythrocyte model). The mineral content was assessed via TXRF spectroscopy, and chemical fingerprinting was conducted using mass spectrometry. Chemometric tools were used for the samples’ discriminating analyses, including Principal Component Analysis (PCA) and Partial Least Squares–Discriminant Analysis (PLS-DA). Seasonal variations significantly affected the moisture, total soluble solids, and acidity. In turn, the antioxidant capacity was influenced mainly by the bee species. The mineral composition, particularly potassium, phosphorus, and calcium, remained stable. Multivariate analysis identified m/z ions (VIP scores > 2.5), rather than physicochemical or antioxidant capacity parameters, as critical for seasonal discrimination. The antioxidant activity, assessed by oxidative hemolysis prevention, was robust across the seasons, with M. mondury honey (2 mg·mL⁻¹) from the rainy season outperforming ascorbic acid. These findings underscore the impact of the rainy and dry seasons and the potential of secondary metabolite fingerprinting to identify collection periods. Full article

This study evaluates the effectiveness of Total Reflection X-ray Fluorescence for multi-element analysis in mussels, focusing on sensitivity, precision, and detection limits. Additionally, it offers a cross-regional comparison of elemental composition in mussels from aquaculture farms in Italy, Spain, and Chile. TXRF, using suspensions of mussel samples, proved effective in detecting minor and trace elements, with recovery rates over 80% for Fe, Cu, Zn, As, and Sr. The research offers a chemical element comparison of Mytilus galloprovincialis and Mytilus chilensis mussels, revealing significant variation based on geographic origin. Correlation matrices demonstrated variable associations between elements, indicating that regional environmental conditions influence bioaccumulation. These findings deepen our understanding of how mussels accumulate elements in different environments. However, further research is needed to develop comprehensive elemental databases and to account for seasonal and temporal variations in mussels’ elemental composition. This study may bring insight for food safety and public health monitoring. Full article

Background: Research on elemental changes in tissues and organs provides valuable information enabling better understanding of the physiological processes occurring in a living organism, as well as the pathogenesis and course of various diseases. They may also contribute to the development of new, more effective, and safer therapeutic strategies. So far, they have been carried out mainly on male individuals because of the easier planning and conducting of experiments as well as the lower variability of the results in comparison with studies involving females. Methods: The significance of incorporating both sexes in research concerning elemental alterations of tissues may be unveiled by data concerning the influence of sex on the physiological levels of selected elements in various rat organs. Therefore, here we determined and compared the levels of P, S, K, Ca, Fe, Cu, Zn, and Se in brains, hearts, kidneys, livers, and spleens taken from male and female rats. To measure the concentrations of the elements in digested tissue samples, ICP-OES and TXRF methods were utilized. Results: Significant differences between male and female rats were found for all the organs examined, and the concentrations of most of the tested elements were higher in males than females. The exception was Fe, the level of which in the kidneys and liver was higher in female rats. Sex influenced the elemental composition of spleen the most. For the brain, heart, kidneys, and liver, differences were sparse and were found mainly for the heavier elements. Full article

Colloidal cadmium telluride (CdTe) nanoplatelets (NPLs) are promising materials for optoelectronic applications, such as photovoltaics and light-emitting diodes, due to their unique optical and electronic properties. However, controlling their growth, thickness, and stoichiometry remains challenging. This study explores the effect of synthesis temperature on the structural, optical, and stoichiometric properties of CdTe NPLs. CdTe NPLs were synthesized at temperatures of 170 °C, 180 °C, 190 °C, and 200 °C using colloidal methods. The resulting NPLs were characterized by UV–Vis absorption spectroscopy, photoluminescence (PL) spectroscopy, transmission electron microscopy (TEM), and total reflection X-ray fluorescence (TXRF) to assess their morphology, structure, and elemental composition. The results showed that the synthesis temperature significantly affected the NPL’s morphology and stoichiometry. Optimal stoichiometry was achieved at 180 °C and 190 °C, with the crystal structure transitioning from zinc blende at lower temperatures to wurtzite at higher temperatures. Optical properties, including luminescence intensity and emission peaks, also varied with temperature. The synthesis temperature is an important parameter in controlling the structural and optical properties of CdTe NPLs. The optimal conditions for obtaining NPLs with the best characteristics were identified at 190 °C, presenting important findings for further optimization of CdTe NPL synthesis for optoelectronic applications. Full article

Colloidal quasi-two-dimensional cadmium chalcogenide nanoplatelets have attracted considerable interest due to their narrow excitonic emission and absorption bands, making them promising candidates for advanced optical applications. In this study, the synthesis of quasi-two-dimensional CdSe NPLs with a thickness of 3.5 monolayers was investigated to understand the effects of synthesis temperature on their stoichiometry, morphology, and optical properties. The NPLs were synthesized using a colloidal method with temperatures ranging from 170 °C to 210 °C and optimized precursor ratios. Total reflection X-ray fluorescence (TXRF) analysis was employed to determine stoichiometry, while high-resolution transmission electron microscopy (HRTEM) and UV-Vis spectroscopy and photoluminescence spectroscopy were used to analyze the structural and optical characteristics. The results showed a strong correlation between increasing synthesis temperature and the enlargement of nanoscroll diameters, indicating dynamic growth. The best results in terms of uniformity, stoichiometry, and optical properties were achieved at a growth temperature of 200 °C. At this temperature, no additional optical bands associated with secondary populations or hetero-confinement were observed, indicating the high purity of the sample. Samples synthesized at lower temperatures exhibited deviations in stoichiometry and optical performance, suggesting the presence of residual organic compounds. Full article

The sublethal toxic effects of pyriproxyfen, an insect juvenile hormone analog (JHA) insecticide, on the circulating metabolite balance in the Neotropical brown stink bug, Euschistus heros, one of the main agronomic pests in South America, were investigated. Our objectives were to evaluate changes in the baseline levels of lipids and carbohydrates, along with three selected micro-elements—nickel (Ni), copper (Cu), and zinc (Zn)—in the hemolymph of adult E. heros, following the application of a predetermined LC₃₀ of pyriproxyfen (single topical application) in fourth-instar nymphs (N4). Hemolymph was sampled using glass capillaries, with the resulting concentrations of lipids and carbohydrates determined through vanillin- and anthrone-positive reactions, respectively, and micro-element analysis was performed through total reflection X-ray fluorescence (TXRF) spectrometry. Lipids are the main and more stable energy metabolites for E. heros, with a proportion of 2:1 compared to carbohydrate levels. A remarkable sensitivity of carbohydrate levels to sublethal pyriproxyfen exposure, irrespective of sex, was observed. Baseline micro-element levels based on untreated control insects indicate sex-based differences in Ni and Zn, but not in Cu, concentrations. After insecticide exposure, the levels of these micro-elements were variable, with Ni and Zn generally decreasing and Cu decreasing in females but nearly doubling in males. The observed disproportion in lipids, carbohydrates, and inorganic micro-elements suggests potential physiological shifts triggered by pyriproxyfen activity in E. heros during late juvenile stages. Full article

A new easy protocol to functionalize the middle layer of commercial surgical face masks (FMs) with Zn and Cu oxides is proposed in order to obtain antibacterial personal protective equipment. Zinc and copper oxides were synthesized embedded in a polydopamine (PDA) shell as potential antibacterial agents; they were analyzed by XRD and TEM, revealing, in all the cases, the formation of metal oxide nanoparticles (NPs). PDA is a natural polymer appreciated for its simple and rapid synthesis, biocompatibility, and high functionalization; it is used in this work as an organic matrix that, in addition to stabilizing NPs, also acts as a diluent in the functionalization step, decreasing the metal loading on the polypropylene (PP) surface. The functionalized middle layers of the FMs were characterized by SEM, XRD, FTIR, and TXRF and tested in their bacterial-growth-inhibiting effect against Klebsiella pneumoniae and Staphylococcus aureus. Among all functionalizing agents, Cu₂O-doped-ZnO NPs enclosed in PDA shell, prepared by an ultrasound-assisted method, showed the best antibacterial effect, even at low metal loading, without changing the hydrophobicity of the FM. This approach offers a sustainable solution by prolonging FM lifespan and reducing material waste. Full article