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Background: Arsenic, classified as a priority pollutant and human carcinogen by the IARC, is subject to stringent regulatory limits in food and water. Among various arsenic species found in water samples, arsenite (As(III)) is identified as the most toxic form. Given the limitations of conventional spectroscopic techniques in speciation analysis, there is a crucial need for innovative and sustainable methodologies that enable arsenic speciation. Simplifying these methodologies is essential for widespread applicability and effective environmental monitoring., Results: This study proposes a simple and cost-effective analytical methodology for speciating inorganic arsenic in water samples. The method involves extracting As(III) into a polymer inclusion membrane (PIM) containing the extractant Cyanex 301 (bis(2,4,4-trimethylpentyl) dithiophosphinic acid), followed by analysis using energy dispersive X-ray fluorescence (EDXRF) spectrometry. The concentration of arsenate was measured after a reduction step using a thiosulfate/iodide mixture. This simple methodology allows a limit of quantification for trivalent arsenic (2 μg L -1 ), which is well below the World Health Organization's recommended maximum permissible level of As in drinking water (10 μg L -1 ). The method that is developed allows the determination of As at trace levels in waters with naturally occurring arsenic., Significance and Novelty: This study represents a significant advance in the field, providing a novel and efficient methodology for arsenic speciation analysis in water samples. By combining the advantages of polymer inclusion membrane (PIM) extraction with energy dispersive X-ray fluorescence (EDXRF) spectrometry, this study offers a cost-effective and environmentally friendly approach to address the critical issue of arsenic contamination in water sources, thereby contributing to enhanced environmental monitoring and public health protection., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

This paper aims to evaluate the product contamination by elemental impurities during the mechanochemical synthesis of praziquantel (PZQ) co-crystal, polymeric dispersion and cyclodextrin complex by grinding. To assess that, PZQ was co-ground with malic acid (MA), Poloxamer F-127 (F-127) and hydroxypropyl-β-cyclodextrin (HPβCD) in high-energy vibrational mills using stainless steel and agate grinding tools, applying different processing time (30 and 90 min). Differential scanning calorimetry and X-ray powder diffraction confirmed the formation of the targeted products, regardless of applied processing time and grinding tool type. After digestion of the solid powder products, the levels of selected elemental impurities were analysed by inductively coupled plasma mass spectrometry (ICP-MS). The analysis revealed that the content of Mg, Ca, and V are below the limit of quantification in all samples analysed. The contents of P and Na are not related to the type of ball mill and reaction time, but to the starting materials themselves, considering that Na is found in HPβCD and MA, while P was found in F-127. The detected Si impurities in the co-ground products can be related to the use of the agate balls and jars, while the presence of Cr and Fe can be related to the use of the stainless steel grinding tools. The risk assessment showed that the oral administration of the prepared co-ground products in quantities corresponding to regular PZQ oral doses resulted in only insignificant exposure to Cr. Finally, the use of agate grinding tools should be preferred, as administration of such products results in lower Cr exposure. The presented elemental impurities did not lead to any significant drug degradation as PZQ content at the end of the six-month testing period was still in the range of 95-105 % of the initial content. Regardless, ICP-MS analysis of the elemental impurities should be considered in regular quality control procedures in the development and production of novel pharmaceutical products prepared by grinding., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Glioblastoma (GBM) is a fast-growing and aggressive brain tumor which invades the nearby brain tissue but generally does not spread to the distant organs. Nonetheless, if untreated, GBM can result in patient death in time even less than few months from the diagnosis. The influence of the tumor progress on organs other than brain is obvious but still not well described. Therefore, we examined the elemental abnormalities appearing in selected body organs (kidney, heart, spleen, lung) in two rat models of GBM. The animals used for the study were subjected to the implantation of human GBM cell lines (U87MG and T98G) characterized by different levels of invasiveness. The elemental analysis of digested organ samples was carried out using the total reflection X-ray fluorescence (TXRF) method, independently, in three European laboratories utilizing various commercially available TXRF spectrometers. The comparison of the data obtained for animals subjected to T98G and U87MG cells implantation showed a number of elemental anomalies in the examined organs. What is more, the abnormalities were found for rats even if neoplastic tumor did not develop in their brains. The most of alterations for both experimental groups were noted in the spleen and lungs, with the direction of the found element changes in these organs being the opposite. The observed disorders of element homeostasis may result from many processes occurring in the animal body as a result of implantation of cancer cells or the development of GBM, including inflammation, anemia of chronic disease or changes in iron metabolism. Tumor induced changes in organ elemental composition detected in cooperating laboratories were usually in a good agreement. In case of elements with higher atomic numbers (Fe, Cu, Zn and Se), 88% of the results were classified as fully compliant. Some discrepancies between the laboratories were found for lighter elements (P, S, K and Ca). However, also in this case, the obtained results fulfilled the requirements of full (the results from three laboratories were in agreement) or partial agreement (the results from two laboratories were in agreement)., (© 2024. The Author(s).)

Two Helichrysum italicum extracts, OPT-1 (rich in phenolic acids) and OPT-2 (rich in total phenols and flavonoids), were prepared using hydroxypropyl-β-cyclodextrin (HP-β-CD)-assisted extraction. The prepared extracts were rich in phenolic compounds, including flavonoids and phenolic acids. GC-MS analysis of the extracts identified neryl acetate, neo-intermedeol, β-selinene, γ-curcumene, italidione I, and nerol as the main volatile components of the extracts, as well as plant sterols, γ-sitosterol, campesterol, and stigmasterol. The antioxidant (DPPH radical scavenging, reducing power, and a carotene linoleic acid assay) and cosmeceutical (anti-hyaluronidase, anti-tyrosinase, anti-lipoxygenase, ovalbumin anti-coagulation, and a UV-absorption assay) activity of the extracts in most of the assays was better than the activity of the applied positive controls. Especially low were the IC 50 values of the extracts in the anti-hyaluronidase (14.31 ± 0.29 μL extract/mL and 19.82 ± 1.53 μL extract/mL for OPT-1 and OPT-2, respectively) and the anti-lipoxygenase (0.96 ± 0.11 μL extract/mL and 1.07 ± 0.01 μL extract/mL for OPT-1 and OPT-2, respectively) assays. The extracts were non-toxic to HaCaT cells in concentrations of up to 62.5 µL extract/mL assuring their status as excellent candidates for cosmeceutical product development appropriate for direct use in cosmetic products without solvent evaporation.

Echinacea purpurea is used in herbal medicinal products for the prevention and treatment of the common cold, as well as for skin disorders and minor wounds. In this study, the efficiency of traditional maceration using water and ethanol was compared with the maceration using mixtures of water and glycerol, a non-toxic, biodegradable solvent from renewable sources. It was found that the glycerol-water mixtures were as effective as ethanol/water mixtures for the extraction of caffeic acid derivatives. All the prepared extracts demonstrated notable antiradical properties. Furthermore, an efficient ultrasound-assisted extraction using glycerol-water mixtures was developed using six independent variables. Their levels needed for the maximum extraction of caffeic acid derivatives were as follows: glycerol 90% ( m/m ), temperature 70 °C, ultrasound power 72 W, time 40 min, and ascorbic acid 0 mg/mL. Under the optimized conditions, ultrasound-assisted extraction was superior to maceration. It achieved significantly higher yields of phenolic acids in shorter extraction time. The presence of zinc in plant material may contribute to the beneficial effects of E. purpurea preparations. Since glycerol is a non-toxic solvent with humectant properties, the prepared extracts can be directly used for the preparation of cosmetics or oral pharmaceutical formulations without the need for solvent removal.

Trace elements are essential for the normal spermatogenesis of mammals and play a critical role in sperm quality and pathological processes e.g. inflammation. Consequently, multi-elemental analysis of seminal plasma (SP) may provide significant information on physiological and pathophysiological processes occurring in the male reproductive tract. Therefore, the development of a simple, fast and reliable method for seminal plasma (SP) analysis by total reflection X-ray fluorescence spectrometry (TXRF) could be useful for both, scientific and clinical studies. In this study, a detailed assessment of the sample preparation parameters and measurement conditions, including analysis of the shape and element distribution of the deposited residue on the reflector by micro X-ray fluorescence spectrometry, was carried out. Using the best analytical conditions, limits of detection for trace elements were found to be in the range of 0.04-0.3 mg kg-1. Trueness and precision of the results, evaluated by spiked SP sample analysis, were in most cases acceptable with recovery values in the range of 87-109% and relative standard deviations 3-12% (n = 5). The developed TXRF method was applied for the analysis of several SP samples from patients with different diagnoses and the results were compared with those obtained by ICP-OES. Among the studied trace elements with a role in the antioxidant defence system only Zn could be quantified and some differences in Zn concentrations among studied groups were observed. However, further studies on a large number of samples are required to define the exact relationship between the element composition and semen quality.

In the present study, we investigated the possibilities and drawbacks of hollow fiber liquid phase microextraction (HF-LPME) combined with total reflection X-ray fluorescence (TXRF) spectrometry for the determination of low amounts of inorganic arsenic (As) species in water samples. The obtained results showed that a three-phase HF-LPME system was more suitable to be used in combination with TXRF than the two phase configuration, since lower detection limit and better precision for As determination can be attained. Relevant experimental parameters affecting As extraction (i.e. types of extractant, organic solvent, agitation speed, pH and extraction time) and TXRF analysis (deposition volume and drying mode) were systematically evaluated. It was found that As(III) was more efficiently extracted at pH 13, whereas, optimum pH for As(V) extraction was at pH 8.5. Limits of detection (LOD) achieved using the best analytical conditions meet the requirements of current legislation and allow the determination of inorganic As(V) and As(III) in water. The proposed method was also applied to different spiked environmental water samples for the preconcentration and subsequent determination of trace inorganic As species., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The broad use of silver nanoparticles (AgNPs) in daily life products enhances their possibilities to reach the environment. Therefore, it is important to understand the uptake, translocation and biotransformation in plants and the toxicological impacts derived from these biological processes. In this work, Lactuca sativa (lettuce) was exposed during 9 days to different coated (citrate, polyvinylpyrrolidone, polyethylene glycol) and sized (60, 75, 100 nm) AgNPs at different concentrations (1, 3, 5, 7, 10, 15 mg L -1 ). Total silver measurements in lettuce roots indicated that accumulation of AgNPs is influenced by size and concentration, but not by nanoparticle coating. On the other hand, nanosilver translocation to shoots was more pronounced for neutral charged and large sized NPs at higher NP concentrations. Single particle inductively coupled plasma mass spectrometry analysis, after an enzymatic digestion of lettuce tissues indicated the dissolution of some NPs. Ag K-edge X-ray absorption spectroscopy analysis corroborated the AgNPs dissolution due to the presence of less Ag-Ag bonds and appearance of Ag-O and/or Ag-S bonds in lettuce roots. Toxicological effects on lettuces were observed after exposure to nanosilver, especially for transpiration and stomatal conductance. These findings indicated that AgNPs can enter to edible plants, exerting toxicological effects on them., (Copyright © 2019 Elsevier B.V. All rights reserved.)

The production of silver nanoparticles (AgNPs) has increased tremendously during recent years due to their antibacterial and physicochemical properties. As a consequence, these particles are released inevitably into the environment, with soil being the main sink of disposal. Soil interactions have an effect on AgNP mobility, transport and bioavailability. To understand AgNP adsorption processes, lab-controlled kinetic studies were performed. Batch tests performed with five different Mediterranean agricultural soils showed that cation exchange capacity and electrical conductivity are the main parameters controlling the adsorption processes. The adsorption kinetics of different sized (40, 75, 100 and 200 nm) and coated (citrate, polyvinylpyrrolidone and polyethyleneglycol (PEG)) AgNPs indicated that these nanoparticle properties have also an effect on the adsorption processes. To assess the mobility and bioavailability of AgNPs and to determine if their form is maintained during adsorption/desorption processes, loaded soils were submitted to leaching tests three weeks after batch adsorption studies. The DIN 38414-S4 extraction method indicated that AgNPs were strongly retained on soils, and single-particle inductively coupled plasma mass spectrometry confirmed that silver particles maintained their nanoform, except for 100 nm PEG-AgNPs and 40 nm citrate-coated AgNPs. The DTPA (diethylenetriaminepentaacetic acid) leaching test was more effective in extracting silver, but there was no presence of AgNPs in almost all of these leachates., (Copyright © 2019. Published by Elsevier B.V.)

Exposure to arsenic (As) through drinking water results in accumulation of As and its methylated metabolites in several organs, promoting adverse health effects, particularly potential development of cancer. Arsenic toxicity is a serious global health concern since over 200 million people are chronically exposed worldwide. Abundant biochemical and epidemiological evidence indicates that the kidney is an important site of uptake and accumulation of As, and mitochondrial damage plays a crucial role in arsenic toxicity. However, non-destructive analyses and in situ images revealing As fate in renal cells and tissue are scarce or almost non-existent. In this work, kidney tissue from exposed rats was analyzed by EDXRF (Energy dispersive X-ray fluorescence), micro-SRXRF (micro X-ray Fluorescence using Synchrotron Radiation), SRTXRF (SRXRF in total reflection condition), SEM-EDX (Scanning Electron Microscope in combination with EDXRF) and SRXRF-XANES (SRXRF in combination with X-ray Absorption Near Edge Spectroscopy). Our results provide evidence of renal cortex distribution of As with periglomerular localization, co-localization of S, Cu and As in subcellular compartment of proximal tubule cells, mono-methylarsonous acid accumulation in renal cortex mitochondria, and altered subcellular concentration and distribution of other elements., (Copyright © 2019. Published by Elsevier Ltd.)

The expansion of silver nanoparticle (AgNP) applications in industry as antibacterial agents has generated an increment of their presence in the environment. Once there, their behavior is not clear because they can undergo different transformation processes that affect their transport, mobility, bioavailability, and toxicity. Therefore, the characterization and quantification of these emerging contaminants are important to understand their behavior and the toxicity effects that can be exerted on living beings. Single particle inductively coupled plasma mass spectrometry (SP-ICPMS) has demonstrated its ability to characterize and give quantitative information on AgNPs in aqueous samples. However, sometimes, the discrimination of the signal corresponding to AgNPs from the signal of dissolved species (Ag(I)) is a challenge. In the present contribution, it is shown that the presence of high amounts of Ag(I) hamper silver nanoparticle size and nanoparticle concentration determination in aqueous samples by SP-ICPMS. To facilitate signal discrimination of both chemical forms, the combination of cloud point extraction (CPE) with SP-ICPMS was studied. CPE experimental conditions to separate AgNPs from Ag(I) were assessed and adapted taking into account the characteristics of the SP-ICPMS technique. CPE and soil matrix effects on particle size were evaluated, showing that particle size was not modified after being in contact with soil matrix and after being separated by CPE. Additionally, frequently used calculation methods for SP-ICPMS data treatment were assessed. Finally, the potential of the developed methodology CPE-SP-ICPMS was evaluated in aqueous soil leachates contaminated with mixtures of AgNPs/Ag(I).

Multielemental analysis of whole blood can provide significant information for the evaluation of nutritional status and diagnosis of certain diseases as well as for the assessment of exposure to potentially toxic metals. However, the quantification of multiple elements in whole blood is not easy partly because of the wide variation in element concentrations (from ng L -1 to g L -1 ) and the complex matrix. The aim of this work was to develop a fast, sustainable, and reliable analytical method, in combination with low-power TXRF, for multielemental analysis of blood samples. Firstly, a set of experiments were carried out to select the best diluent type and dilution factor using the control material SeronormTM Trace Elements Whole Blood L-1. A critical evaluation of the parameters affecting the sample deposition on the reflector was also carried out including a study of the shape and element distribution of the deposited residue on the reflector by micro X-ray fluorescence spectrometry. Using the best analytical conditions, limits of detection estimated were in the low milligrams per kilogram range and similar to those obtained using more complex sample treatments such as digestion. Accuracy and precision of the results were in most cases acceptable (recoveries 89-102%, RSD 6-8%, n = 5). Only underestimated values were obtained for light elements such as potassium. To prove the applicability of the method, several blood samples from control and thyroid disease patients were analyzed. Despite the fact that more samples need to be analyzed, it seems that Zn and Br contents in some of the patients are significantly higher compared to control samples. Graphical abstract.

Due to the current use of gold nanoparticles (AuNPs) in many fields and their potential dissolution/transformation into ionic gold (Au 3+ ), there is an increasing interest in methods enabling the discrimination of Au 3+ from AuNPs in environmental samples. In this contribution, the combination of a novel ligandless surfactant-assisted emulsification microextraction procedure (LL-SAEME) with total reflection X-ray fluorescence spectrometry (TXRF) is proposed for the isolation and preconcentration of Au 3+ in aqueous extracts containing AuNPs. The method is fast, simple, and involves low operating costs and low consumption of reagents in comparison with other spectroscopic methods. It is based on the formation of a gold hydrophobic compound with the cationic surfactant cetyltrimethylammonium bromide (CTAB) which is extracted in a few microliters of 1,2-dichloroethane. After shaking the solution by hand for 5 s, the mixture is centrifuged for 3 min at 2000 rpm and 5 μL of the organic phase containing the gold ions are deposited on a quartz reflector to carry out the TXRF analysis. Using this approach, the limit of detection for gold was 0.05 μg/L and a good linearity ( R 2 > 0.99) was assessed in the range of 1-500 μg/L. Moreover, no matrix effects were observed when ionic gold was extracted from different types of water such as river, mineral, and tap waters as well as in synthetic aqueous solutions containing other ions, AuNPs, and dissolved organic matter. As a study case, the developed LL-SAEME-TXRF method was applied to monitor AuNPs stability in soils in laboratory-controlled experiments by means of Au 3+ monitoring over time.

Alumina supported on graphene oxide (Al 2 O 3 /GO) nanocomposite as new nanosorbent in dispersive micro-solid phase extraction (DMSPE) for As(V) and Cr(III) preconcentration is described. The crucial issue of the study is synthesis of novel nanocomposite suitable for sorption of selected species of arsenic and chromium. Al 2 O 3 /GO demonstrates selectivity toward arsenates in the presence of arsenites at pH 5 and chromium(III) ions in the presence of chromate anions at pH 6. The Al 2 O 3 /GO nanocomposite was characterized by scanning electron microscopy (SEM) transmission electron microscopy (TEM), powder X-ray diffraction (XRD) and the Raman spectroscopy. The maximum adsorption capacity calculated based on the Langmuir adsorption model were 43.9 mg g -1 and 53.9 mg g -1 for As(V) and Cr(III), respectively. The nanocomposite was used as solid sorbent in preconcentration of As(V) and Cr(III)_ions from water samples and their determination using energy dispersive X-ray fluorescence spectrometry (EDXRF). The As(V) and Cr(III) ions can be quantitatively preconcentrated from 25 to 100 mL aqueous samples within 5 min using DMSPE procedure and 1 mg of Al 2 O 3 /GO. The nanocomposite was also used for preparation of Al 2 O 3 /GO membrane. Then, As(V) and Cr(III)_ions can be retained under flow condition by passing analyzed solution through Al 2 O 3 /GO membrane. Under the optimized conditions, As(V) and Cr(III) ions can be determined with very good recovery (92-108%), precision (RSD 2.7-4.0%) and excellent limit of detection (0.02 ng mL -1 As and 0.11 ng mL -1 Cr). The accuracy of the method was studied by analyzing certified reference materials (NIST 1640a) and spiked real water samples., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Sewage sludge is used as a fertilizer replacement in agricultural soils for its chemical properties, such as organic matter content, and for its capability to improve physical soil characteristics like porosity. This is also an appealing disposal option for residue whose production is increasing worldwide. However, there is some concern about the presence of potentially toxic elements (PTEs) that can accumulate in soils and become available for crops. In this work, a study was conducted to evaluate the extractability and crops transfer of thirteen PTEs from soils that had been amended with biosolids each year for 15 years as a regular agricultural practice. The study was conducted with barley (winter cereal) and maize (spring cereal) crops. After this long period, an increase in the amount of Pb, Hg, Zn and Ag in soils amended by biosolids was confirmed. However, it is important to emphasize that the PTE total content in croplands was still far below the thresholds established by US and European regulations. Statistically significant differences were also found between the soils fertilized with biosolids and other treatments compared with the potential phytoavailable amount of Cu, Se, Sb and especially for As and Zn, by a DTPA leaching test. Despite these results, the concentration of PTEs in the barley and maize grains grown in fields repeatedly amended with biosolids was not statistically different from those grown with chemical fertilization, except for As in barley grains. In this case, a significant correlation was found between the DTPA-extractable As content in soils and the total content in grains (r = 0.83)., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

A nanocomposite prepared from graphene nanosheets and cerium nanoparticles (G/CeO 2 ) was applied to the extraction of Se(IV), As(V), As(III), Cu(II) and Pb(II). The structure of G/CeO 2 was investigated by scanning electron microscopy, X-ray diffraction and Raman spectroscopy. The optimal pH values for extraction are 4.0 for As(V), 3.0 for Se(IV), and 6.0 for both Cu(II) and Pb(II). The maximum adsorption capacity of G/CeO 2 (expressed as mg·g -1 ) were calculated by the Langmuir model and are found to be 8.4 for As(V), 14.1 for Se(IV), 50.0 for Cu(II) and 75.6 for Pb(II). The sorbent was applied to dispersive solid phase microextraction prior to direct quantitation by energy-dispersive X-ray fluorescence spectrometry without the need for prior elution. The limits of detection (in ng·mL -1  units) are 0.10 for As(V), 0.11 for Se(IV), 0.19 for Cu(II) and 0.21 for Pb(II). The precisions (RSDs) are <4.5%. The accuracy of the method (1 - 4%) was verified by analysis of the certified reference material (CRM 1640a - natural water). The method was successfully applied in ultratrace element determination and to the speciation of selenium in environmental waters. Graphical abstract The method gives possibility of simultaneous preconcentration and determination in environmental waters of both anionic (As(V) and Se(IV)) and cationic (Cu(II) and Pb(II)) forms of selected metals using graphene nanosheets and cerium nanoparticles. Se(IV) can be selective determined in the presence of Se(VI).

A novel and simple method is presented for the preconcentration and determination of mercury (Hg) from natural waters through its extraction into a polymer inclusion membrane (PIM) containing the task-specific ionic liquid trioctylmethylammonium thiosalicylate (TOMATS) followed by Energy Dispersive X-ray fluorescence (EDXRF) analysis. The determination was made directly on the membrane without any treatment or elution step, and due to the characteristics of the PIM no matrix or thickness corrections were required in EDXRF analysis. Under the best extracting and EDXRF operating conditions, a Hg limit of detection of 0.2 μg Hg L -1 was obtained. Moreover, no water matrix effect was observed when Hg was extracted from different types of water such as river, seawater, groundwater, and tap water, showing this extraction system as a global solution when dealing with natural waters. Interestingly, this Hg collected in the PIM has shown to be stable for at least 6 months without the use of any preservative. This fact is of prime importance taking into account the usual stability problems of Hg during sample storage.

Graphene oxide decorated with cerium(IV) oxide (GO/CeO 2 ) was synthesized and applied in adsorption of several metal ions such as As(III), As(V), Se(IV), Cu(II), and Pb(II) from aqueous samples. The important feature of GO/CeO 2 nanocomposite is also its selectivity toward selenite in the presence of selenate. The structure of GO/CeO 2 has been proven by microscopic and spectroscopic techniques. The maximum adsorption capacities of GO/CeO 2 calculated by Langmuir model toward arsenic, selenium, copper, and lead ions are between 6 and 30 mg g -1 . An interesting feature of this adsorbent is its excellent dispersibility in water. Thus, GO/CeO 2 nanocomposite is ideal for fast and simple determination of heavy metal ions using dispersive microsolid phase extraction (DMSPE). Moreover, coupling DMSPE with energy-dispersive X-ray fluorescence spectrometry (EDXRF) is extremely beneficial because it allows direct analysis of adsorbent. Thus, the analyte elution step, as needed in many analytical techniques, was obviated. The influence of sample volume and the sorption time as well as the influence of foreign ions and humic acid on the recovery of determined elements are discussed in the paper. The results showed that developed methodology provided low limits of detection (0.07-0.17 μg/L) and good precision (RSD < 4%). The GO/CeO 2 nanocomposite was applied to analysis of real water samples and certified reference materials (CRM) groundwater (BCR-610) and pig kidney (ERM-BB186).

Energy dispersive X-ray fluorescence spectrometry (ED-XRF) is widely used in art and cultural heritage for direct measurements and elemental quantification of solid samples. However, in the literature there are not works dealing with the quantitative application of ED-XRF to liquid extracts coming from samples belonging to cultural heritage. In this work, a novel methodology based on the use of ED-XRF spectrometry after thin film deposition on special sample retainers and a subsequent evaporation was developed to quantify light elements (Z ≤ 20) in aqueous extracts and heavy elements (Z > 20) in acid extracts, coming from materials and degradation products belonging to built heritage (mortars, black crusts, and calcium carbonate formations). For this purpose, special sample retainers were used instead of more common adsorbent filter papers. Three different ED-XRF calibration methodologies were designed as elemental quantification tools and "green chemistry" alternatives to conventional techniques. On the one hand, the developed external ED-XRF calibration methodology for elements with Z ≤ 20 was proposed as an alternative to ion chromatography to obtain information about the degradation processes that the building materials suffered. On the other hand, the external ED-XRF calibration for elements with Z > 20 in acid extracts was optimized as a faster and cleaner quantification alternative to inductively coupled plasma mass spectrometry (ICPMS). Finally, with the aim to reduce the matrix effect and to improve the quantitative results for elements with Z > 20 in acid extracts, a novel ED-XRF calibration methodology based on standard additions was successfully designed and applied to real samples belonging to built heritage.

In 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 20mg 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., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

The present contribution presents a preliminary investigation of the chemical composition with respect to major, minor, trace, and ultratrace elements in several clam species that are frequently used for human consumption in Portuguese markets and worldwide. In order to use a simple and rapid analytical methodology for clam analysis, energy dispersive X-ray fluorescence (EDXRF) spectrometry and total reflection X-ray fluorescence (TXRF) spectrometry were selected as analytical techniques. The analytical capabilities of TXRF spectrometry were evaluated for the determination of minor and trace elements in commercial edible clams. We compared the direct analysis of powdered suspensions (using different sample amounts and dispersant agents) with the analysis of the digested samples for trace element determination. Inductively coupled plasma mass spectrometry analysis of clam digests was also performed to evaluate the analytical possibilities of TXRF spectrometry for trace and ultratrace analysis.

In the present study, and taking into account the microanalytical capability of total reflection X-ray spectrometry (TXRF), we explored the possibilities of hollow fibre liquid-phase microextraction (HF-LPME) and dispersive liquid-liquid microextraction (DLLME) combined with TXRF for the determination of low amounts of inorganic Sb species in waters. For each of the LPME configurations aforementioned, experimental parameters affecting Sb extraction but specially the proper sample preparation process (deposition volume on the reflective carrier and drying mode) and measurement conditions for subsequent TXRF analysis have been carefully evaluated. The best analytical strategy for the determination of Sb(III) and Sb(V) in the low μg L(-1) range was found to be the application of the DLLME mode before TXRF analysis. The developed methodology was successfully applied to the determination of inorganic Sb speciation in different types of spiked water samples., (Copyright © 2013 Elsevier B.V. All rights reserved.)

A methodology based on dispersive micro solid-phase extraction (DMSPE) using multiwalled carbon nanotubes (MWCNTs) as solid sorbent prior to measurement with energy-dispersive X-ray fluorescence (EDXRF) spectrometry is proposed. The procedure consists of chelating of nickel, cobalt, copper, and lead ions with ammonium pyrrolidinedithiocarbamate (APDC) and posterior adsorption of metal chelates on MWCNTs (1 mg) dispersed in the aqueous samples (100 mL). DMSPE promotes immediate interaction between the metal chelates and MWCNTs and shortens time of sample preparation in comparison with classical solid-phase extraction. After microextraction process, MWCNTs are collected onto filter and directly measured by EDXRF. With this technique, the direct quantification of metal species held in solid materials is possible and, therefore, the elution step can be avoided. The effects of various experimental parameters such as pH of the solution, amounts of MWCNTs and APDC, sample volume, and time of stirring were investigated. With the best analytical conditions (1 mg of MWCNTs, 2 mg of APDC, 100 mL sample volume, pH = 7, and 5 min time of stirring), Co(II), Ni(II), Cu(II), and Pb(II) can be simultaneously determined with very good recoveries (101%, 98%, 96%, 99%, respectively) and detection limits (0.43, 0.11, 0.46, 0.15 ng mL(-1), respectively). The method was applied in determination of trace metal ions in tap water and wastewater samples.

The determination of hexavalent chromium (Cr(VI)) in cement-related material extracts is frequently monitored in cement industries to comply with the European Directive (2003/53/EC) that limits the use of cements containing more than 2 mg kg(-1) of water-soluble Cr(VI). In the present work, a rapid and simple method for the determination of water-soluble Cr(VI) in clinker samples has been developed. The analytical methodology is based on the combined use of a low cost Cr(VI) isolation procedure using activated layers followed by their analysis using wavelength-dispersive X-ray fluorescence (WDXRF) spectrometry. WDXRF instrumentation is a common tool used for determining the chemical composition of all materials involved in cement production and also for the quality control of the products produced in cement and concrete factories. Therefore, the presented methodology does not imply the use of additional instrumentation in cement-industries laboratories and can be used as a comparative method to the spectrophotometric reference (EN 196-10:2006). The analytical parameters evaluated (selectivity, limit of detection, linearity, and precision) prove to be suitable for the intended purpose, and the methodology has successfully been applied to determine water-soluble Cr(VI) in several clinker samples.

The accuracy and precision of lead isotope ratio measurements by quadrupole-based inductively-coupled plalsma-mass spectrometry (ICP-MS) can be limited by any of a number of instrumental factors being mass bias one of the most relevant. Mass bias can be defined as the deviation of measured isotope ratios from the "true value" due to the different transmission of ions according to their masses before the final detection. In the present research, a systematic study aimed at obtaining a more profound insight into to what extent the potential of the ion optic system and gas-filled octapole collision cell influence the mass discrimination in lead isotopic measurements ((206)Pb/(207)Pb, (208)Pb/(207)Pb and (206)Pb/(208)Pb) using ICP-QMS instrumentation was carried out. From the results obtained, it could be concluded that, in most cases, the effect of ion lens potential variation in mass discrimination is not really significant when working in maximum ion intensity regions. On the other hand, the application of pressurized conditions in the octapole collision/reaction cell using He and H(2) as target gases does not lead to an improvement in ion sensitivity but, instead, introduces a significant mass bias effect, particularly when using high He flow rates (6-8 mL min(-1)). In this latter case, the use of Tl as the internal standard ((203)Tl/(205)Tl) proved to be suitable to correct the mass bias drift and the calculated mass discrimination percentage values decreased from 3.61% to 0.33%. The use of the gas-filled octapole collision cell does not lead to an improvement in lead isotope ratio precision compared to vented conditions.

In this paper, we describe a new method for trace level Cd determination in complex environmental liquid samples. Thin layers activated with the extractant Aliquat 336 were prepared either by direct impregnation of commercial polymeric supports or by physical inclusion in a cellulose triacetate matrix, and both were effectively used to collect Cd present at low concentration in different aqueous matrixes. Quantitation of Cd contained in the thin layers was performed by high-energy polarized-beam energy-dispersive X-ray fluorescence. The effects of various experimental parameters such as layer composition, equilibration time, and instrumental conditions have been investigated. The analysis of different impregnated layers contacted with solutions ranging from 5 to 8000 microg L-1 Cd showed a linear response between the Cd concentration in the aqueous solutions and the metal present in the thin layer, with a detection limit of 0.7 microg L-1. The accuracy of the proposed method was confirmed by analyzing spiked seawater samples and a synthetic water sample containing, besides Cd, high amounts of other metal pollutants such as Ni, Cu, and Pb. The attained results were comparable to those obtained by anodic stripping voltammetry or inductively coupled plasma spectrometry.