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The extraction of total Cr(VI) from commercially available cements, based on DTPA + 0.2 mol dm -3 (NH4)2SO4/NH4OH mixture solution and subsequent selective determination of Cr(VI) has been proposed. The determination was carried out using the adsorptive voltammetric stripping method. The study was conducted using three different commercially available cement samples. It has been checked that the proposed extraction procedure guaranteed no changes of chromium speciation during cement analysis. For comparison extraction was also carried out with the use of recommended by United States Environmental Protection Agency (EPA) Method 3060A, based on 0.28 mol dm -3 Na2CO3 + 0.5 mol dm -3 NaOH). Additionally, the extraction process was carried out using only distilled water as an extraction mixture which allows to evaluate concentration of only soluble Cr(VI) forms contained in cement. In all three cements, the content of soluble Cr(VI) was below 2 ppm, i.e. the limit value by European Union Directive 2003/53/EC. [ABSTRACT FROM AUTHOR]

The separation of unchanged As(III) species, just after sampling, is crucial for reliable speciation analysis of that element in water systems. In the presented paper, a simple and quick procedure is described for As(III) separation from a water matrix on the sampling site, integrated with speciation analysis using ICP-MS. For the separation of As(III) anions, a C18 column was saturated with APDC. The acidification of the water sample to pH 2 ensured 100% retention of As(III) anions and effective separation from As(V), MMA and DMA. C18 columns modified with APDC can be prepared and stored in the laboratory for up to 24 hours before use on the sampling site. The influence of Pb, Cd, Tl, and Cr cations can be limited with the addition of EDTA. Anions such as SO42− and PO43− do not significantly affect the efficiency of As(III) anion retention. [ABSTRACT FROM AUTHOR]

Anion-exchange chromatography (Hamilton, PRP-X100) with hydride-generation atomic fluorescence spectrometry (HG-AFS) is commonly used for selenium (Se) speciation analysis in environmental and biological samples. However, retentions of Se species are often different with different mobile phases. To address it, this study systematically investigated mobile phases based on ammonium salts to obtain good resolution of Se species. Various mobile phases, including NH4H2PO4, NH4Ac, NH4NO3 and (NH4)2HPO4, were tested. The best result was obtained with a mobile phase containing 60 mmol L−1 (NH4)2HPO4 at pH 6.0, where the separation of Se species, including selenite [Se(IV)], selenate [Se(VI)], selenocystine (SeCys) and selenomethionine (SeMet), was achieved within 10 min with reasonable resolution. In addition, the recoveries of SeCys, Se (IV), SeMet and Se (VI) in the Se-enriched samples were 95.72 ± 1.60%, 106.89 ± 2.20%, 93.28 ± 2.82% and 91.38 ± 1.27%, respectively. Finally, the proposed method was validated for the determination of Se species in Nicotiana tabacum tissues.

The use of UV and Vis light (in the form of solar energy) in the presence of semiconductor nanostructured materials as photocatalysts is effective for the adequate removal of a wide spectrum of pollutants (resistant to other degradation techniques) in various types of wastewater, which are important elements of the development of science related to photocatalysis. Research related to the application of photoactive materials for the catalytic degradation /simplification/decomposition of water pollutants has high application potential and should be continued. A UV-vis spectrophotometer scanned the photocatalytic competences of the synthesized nanomaterials through the degradation of methylene blue and methyl orange dyes. [Extracted from the article]

Coal-seam fire is a source of atmospheric mercury that is difficult to control. The Wuda Coalfield in Inner Mongolia, China, is one of the most severe coal fire disaster areas worldwide and has been burning for more than 50 years. To investigate atmospheric mercury pollution from the Wuda coal fire, gaseous elemental mercury (GEM) concentrations and atmospheric particulate mercury (PHg) speciation were measured using a RA-915+ mercury analyzer and the temperature-programmed desorption method. Near-surface GEM concentrations in the Wuda Coalfield and adjacent urban area were 80 ng m−3 (65–90 ng m−3) and 52 ng m−3 (25–95 ng m−3), respectively, which are far higher than the local background value (22 ng m−3). PHg concentrations in the coalfield and urban area also reached significantly high levels, 33 ng m−3 (25–45 ng m−3) and 22 ng m−3 (14–29 ng m−3), respectively (p < 0.05). There is no clear evidence that PHg combines with organic carbon or elemental carbon, but PHg concentration appears to be controlled by air acidity. PHg mainly exists in inorganic forms, such as HgCl2, HgS, HgO, and Hg(NO3)2·H2O. This work can provide references for the speciation analysis of atmospheric PHg and the safety assessment of environmental mercury. [ABSTRACT FROM AUTHOR]

The amyloid β peptide, as one of the main components in senile plaque, represents a defining pathological feature for Alzheimer's disease, and is therefore commonly used as a biomarker for this disease in clinical analysis. However, the selection of suitable standards is limited here, since only a few are commercially available, and these suffer from varying purity. Hence, the accurate characterization of these standards is of great importance. In this study, we developed a method for the traceable quantification of the peptide content using species-specific isotope dilution and ICP-MS/MS detection. It is based on the separation of the sulfur-containing amino acids methionine and cysteine after oxidation and hydrolysis of the peptide. Using a strong anion exchange column, both amino acids could be separated from each other, as well as from their oxidized forms and sulfate. The sulfur content was determined via ICP-MS/MS using oxygen as reaction gas. Species-specific isotope dilution was enabled by using a 34S-labeled yeast hydrolysate, containing methionine sulfone and cysteic acid with different isotopic composition. The peptide contents of Aβ standards (Aβ40,42), as well as myoglobin and lysozyme with different degrees of purity, were determined. For validation purposes, the standard reference material NIST 2389a, which contains the amino acids in a similar concentration, was subjected to the developed sample preparation and analysis method. In addition to accounting for errors during sample preparation, high levels of accuracy and precision could be obtained using this method, making it fit-for-purpose for the characterization of peptide standards. [ABSTRACT FROM AUTHOR]

In this article, low-molecular-weight organic acids were applied to remediate the hexavalent chromium [Cr(VI)]-contaminated soil. The influence of different parameters (washing concentration, solid–liquid ratio, time, and pH value) on the repair effect was explored, and the form distribution and desorption kinetic experiments of the soil were performed. The results show that the pH of eluents can significantly affect the form distribution of chromium, with the exchangeable form increasing considerably at a lower pH. The kinetics of Cr(VI) desorption can be described by the pseudo-second-order kinetics equation. The best washing scheme was determined to be the citric acid as the eluent at a concentration of 0.3 mol/L, a solid to liquid ratio of 1:10, pH 4, and a washing time of 6 h. The removal rate can be as high as 73.52%. After washing, the leaching concentration of Cr(VI) in the soil was reduced from 23.76 to 1.05 mg/L, well below the regulatory constraint of 5 mg/L. Additionally, the characterizations of X-ray diffractometer and scanning electron microscope showed little effect of adopting citric acid as a washing agent on soil structure and surface morphology. This study can provide a theoretical basis for the remediation of Cr(VI)-contaminated soil at industrial sites. [ABSTRACT FROM AUTHOR]

Chemical elements speciation analysis of food samples has been among the most important scientific topics over the last decades. Food samples are comprised of high variety of chemical compounds, from which many can interact with metals and metalloids, forming complex elemental species with various influence on the human body. It is particularly important not only to determine the amount of certain chemical element in food sample but also to identify the form in which given element occurs in given sample. Employment of bespoke and nontargeted speciation methods, with the use of liquid chromatography inductively coupled plasma mass spectrometry (LC/ICP‐MS) and complementary techniques, provides more complete picture on the metals and metalloids speciation in food. This review discusses issues concerning speciation analysis of metals and metalloids in food samples with the use of LC/ICP‐MS as a leading technique in elemental speciation nowadays and a complimentary technique intended for their identification. © 2020 John Wiley & Sons Ltd. Mass Spec Rev [ABSTRACT FROM AUTHOR]

Traditional Chinese medicine contains arsenic (As), which in the natural environment accumulates in plants during the growth of Chinese medicinal materials; there are mineral medicines containing As in Chinese patent medicine such as As4S4, As2S3, etc. Due to the toxicity of As-containing compounds and its role in inflammation and treatment of cancers such as leukemia, it is necessary to analyze the chemical form of As. A comprehensive investigation of the compound forms of heavy metals rather than the simple total amount of elements will lay the foundation for the scientific and objective evaluation of the safety of heavy metals. This article summarizes the speciation of As in bulk Chinese medicinal materials and Chinese patent medicines in recent years, and reviews the main research methods of As speciation analysis. The separation and detection combined analysis method focuses on the highperformance liquid chromatography-plasma mass spectrometry and high-performance liquid chromatography-hydride generation-atomic fluorescence spectroscopy, etc. Taking the advanced synchrotron radiation source as the research platform, the use of X-ray near edge absorption fine structure spectrum and micro-area X-ray fluorescence analysis as a microscopic analysis technique supports direct analysis of the As speciation in situ. It is the most promising morphological analysis method. [ABSTRACT FROM AUTHOR]

The “Lagunas de Montebello” National Park located in Chiapas, Mexico, is well known for its crystal blue water bodies, some of which, in 2003, started to change color from crystalline to cloudy brown, and occasionally emit a foul smell, contains white-yellowish supernatant debris and dead fish. To determine the causes of the changes in the water characteristics of the “Liquidambar” lagoon of the Montebello lagoon system, a physicochemical characterization was carried out over the first six meters of the water column, together with geochemical speciation analysis and the saturation index calculation for different minerals. Water was classified as calcium-sulfated and the main mechanism that controlled its chemistry was rocks dissolution. Sulfide was found at all sampled depths in the range of 0.11 to 1.13 mg.L-1. The concentration of sulfate in the water column ranged from 249.21 to 298.7 mg.L-1, carbonate ranged from 140.5 to 261.4 mg.L-1, calcium and magnesium ranged from 94.5 to 146.9 mg.L-1 and 34.2 to 38.3 mg.L-1, respectively. Likewise, oxygen was also found to be oversaturated on the surface with a value of 9.32 mg.L-1. The speciation results and SI indicated that the mineral phases calcite, aragonite, and dolomite were oversaturated, being greater on the surface. The results suggested the possibility that the turbidity, the coloration change, and the whitish supernatant were due to the precipitation of carbonate minerals, microbiologically influenced by the photosynthetic activity in the upper layer of the lagoon water. [ABSTRACT FROM AUTHOR]

Ecological speciation entails divergent selection on specific traits and ultimately on the developmental pathways responsible for these traits. Selection can act on gene sequences but also on regulatory regions responsible for gene expression. Mimetic butterflies are a relevant system for speciation studies because wing colour pattern (WCP) often diverges between closely related taxa and is thought to drive speciation through assortative mating and increased predation on hybrids. Here, we generate the first transcriptomic resources for a mimetic butterfly of the tribe Ithomiini, Melinaea marsaeus, to examine patterns of differential expression between two subspecies and between tissues that express traits that likely drive reproductive isolation; WCP and chemosensory genes. We sequenced whole transcriptomes of three life stages to cover a large catalogue of transcripts, and we investigated differential expression between subspecies in pupal wing discs and antennae. Eighteen known WCP genes were expressed in wing discs and 115 chemosensory genes were expressed in antennae, with a remarkable diversity of chemosensory protein genes. Many transcripts were differentially expressed between subspecies, including two WCP genes and one odorant receptor. Our results suggest that in M. marsaeus the same genes as in other mimetic butterflies are involved in traits causing reproductive isolation, and point at possible candidates for the differences in those traits between subspecies. Differential expression analyses of other developmental stages and body organs and functional studies are needed to confirm and expand these results. Our work provides key resources for comparative genomics in mimetic butterflies, and more generally in Lepidoptera. [ABSTRACT FROM AUTHOR]

Copyright of Modern Food Science & Technology is the property of Editorial Office of Modern Food Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The aim of this work was to develop a method using high performance liquid chromatography coupled with hydride generation atomic fluorescence spectrometry (HPLC-HG-AFS) for the determination and speciation analysis of the inorganic and organic species of arsenic found most often in rice samples: As(V), As(III), monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA). The best chromatographic resolution was obtained using pH 6.2, a phosphate buffer mobile phase concentration of 20 mmol L-1 and flow rate of 0.57 mL min-1, HCl concentration of 5.55% (v/v), and NaBH4 concentration of 0.90% (w/v). The accuracy of the method was confirmed by the low relative error values obtained for analysis of a certified reference material (NIST 1568b): 6.63% (total inorganic As), 3.44% (DMA), 0% (MMA), and 0.53% (total As). In recovery tests, the proposed method achieved satisfactory recoveries in the range 86-110%.

BACKGROUND Available selenium is an important index to evaluate the supply capacity of selenium from soil to plants. However, there is no national standard method to test available selenium in China. The selection of extractants is very important for the accurate determination of available selenium. OBJECTIVES To determine the optimum extractant based on the correlation between available selenium and selenium species. METHODS Four extractants, sodium bicarbonate, potassium dihydrogen phosphate, nitric acid and hydrochloric acid, were selected to extract the available selenium from vegetable and orchard soils in Tianjin. Atomic fluorescence spectrometry was used to determine the content of various forms of selenium, and the minimum, 25 percentile, median, 75 percentile, maximum value of the effective selenium and water-soluble+ion-exchange+carbonate-combined selenium were used for comparative analysis and the difference. RESULTS The average content of available selenium extracted from vegetable soils by sodium bicarbonate and potassium dihydrogen phosphate was 0.039mg/kg, which was higher than that of nitric acid and hydrochloric acid. The contents of available selenium extracted from orchard soils by sodium bicarbonate, potassium dihydrogen phosphate, nitric acid and hydrochloric acid decreased in turn. The minimum, 25 percentile, median, 75 percentile, and maximum values of available selenium extracted by potassium dihydrogen phosphate in the two soils were closer to the content of sum of water-soluble, ion-exchange and carbonate combined selenium. CONCLUSIONS Potassium dihydrogen phosphate with a concentration of 0.1mol/L was the optimum extractant of available Se for vegetable and orchard soils in Tianjin.

The data gap in food safety regulations have created misinformation leading to the rejection of commodities for trade. The evidence presented is the local regulation of arsenic in sea produce which is based on total arsenic, tAs, instead of toxic inorganic arsenic, iAs. Furthermore, tAs data in animal origin seafood has been widely proven to be dominated by the non-toxic Arsenobetaine, AsB. Therefore, if arsenic regulatory limit was set based only on tAs without reference to iAs data, seafood products might be wrongfully rejected for trade because of non-compliance to tAs limit. We provided analysis of tAs and iAs of 14 local prawn and shrimp commodities from three shrimp/prawn sector namely aquaculture (n = 3), capture (n = 5) and processed (n = 6) using effective extraction, as well as, a fit-for-purpose analytical method for iAs. A HVG-AAS method was developed and validated for iAs with LoQ of 1.6 ppb, analytical range of 0-6 ppb, repeatability RSDr of 0.5-3.1 %, coefficient of determination R 2 of 0.9975, and percentage recovery of 90.9 %, while an existing method using ICP-MS was used to verify the tAs. Based on the AOAC Official Method 999.10 2005 with minor adjustments, seafood samples were digested with concentrated nitric acid and hydrogen peroxide under pressure in a closed vessel heated by a microwave digester. An additional step for iAs determination was necessary to ensure compatibility in HVG-AAS analysis. Further subdivision of the aquaculture and capture samples was done by dividing them into 3 fractions, namely head, flesh and peel. Comparison of tAs in all the three fractions indicated that for aquaculture sector, the highest tAs were found in the flesh (2nd highest in % weight) whereas for the capture sector, the highest amount of tAs correlated with the highest % weight of the fraction. On regulatory aspects, speciation analysis on the iAs indicated samples with quantifiable iAs value were in-compliance despite tAs were initially found to be higher than the national limits. Risk assessment of iAs indicated there were no risk for human daily intake based on the BDML 0.5 value of 3.0 μg/kg b.w per day for an average 70 kg man. All findings concluded the need for doing arsenic speciation analysis of iAs along with tAs for routine monitoring of prawn/shrimp samples and to revise the local limits from tAs to iAs particularly for seafood commodities., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Muhamad Hilmi Md Taib reports administrative support and equipment, drugs, or supplies were provided by 10.13039/100009647Ministry of Health Department of Scientific Services. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

Rocky resertification in Guangxi is widely distributed and becomes one of the serious ecological problems. The Hg pollution in some rocky desertification areas is more prominent. In order to understand the influence of rocky desertification degree on speciation and mobility of heavy metal mercury, different rocky desertification soils(potential rocky desertification, light rocky desertification, medium rocky desertification and severe rocky desertification) with high mercury background value were collected in Huanjiang of Guangxi. The mercury speciation was analyzed by three-step continuous extraction method recommended by Environmental Protection Agency(The mercury was divided into moving dynamic, semi-dynamic and non-moving dynamics). The relationship between mercury content and soil properties of different components in soil, and the mobility and transformation law of mercury in soils of different rocky desertification grades were discussed. The results showed that the content of mercury in high background rocky desertification soil ranged from 0. 3 to 4. 5 mg/ kg, with an average of 3. 46 mg/ kg. The main form of mercury was half migration, accounting to 69%-80% of the total mercury content, with an average of 75. 3%. The pH, cation exchange capacity, organic matter and mobile mercury were negatively correlated, while the total iron, total manganese, total aluminum, free iron oxide and free manganese oxide were positively correlated. The degree of rocky desertification promoted the increase of total mercury concentration, but also promoted the transformation of soil mercury form to mobile mercury, and the mobility of soil mercury. [ABSTRACT FROM AUTHOR]

[Display omitted] • Chemical speciation controls metal ion bioavailability in mammalian cell cultures. • Equilibrium modeling is a good first step, for example, using the Visual MINTEQ program. • Real-time speciation analysis is essential to identify when kinetics is important. • Capillary electrophoresis can quantify specific metal-chelating agent complexes. • Cell metabolism and product quality are influenced by metal ion bioavailability. Upstream process development seeks to optimize media formulations to promote robust cell culture conditions and regulate product quality attributes such as glycosylation, aggregation, and charge variants. Transition metal ions Mn, Fe, Cu, and Zn present in cell culture media have a significant impact on cell growth, metabolism and product quality. These metals and other media components can have different chemical associations or speciation in media that are poorly characterized but may significantly impact their properties and effect on cellular performance. Computer-based equilibrium models are a good starting point for exploring metal speciation, bioavailability and conditions where precipitation may occur. However, some equilibrium constants, especially for newly introduced medium components, have not been experimentally determined. Owing to concurrent physical and biological processes, speciation may also be controlled by reaction kinetics rather than by equilibrium. These factors highlight the importance of analytically interrogating medium speciation to gain insights into the complex interconnections between media components and bioprocess performance. [ABSTRACT FROM AUTHOR]

The study aims to clarify the current controversy related to conflicting reports on whether presence of Cr(VI) in rice is possible or not. For this purpose, a method was employed for the single run speciation analysis of Cr(III) and Cr(VI) in rice samples using species-specific isotope dilution (SS-ID) and high performance liquid chromatography coupled to inductively coupled mass-spectrometry (HPLC-ICP-MS) and selective single run species complexation/derivatisation. The quantification limits (LOQs) were 0.014 μg kg−1 for Cr(III) and 0.047 μg kg−1 for Cr(VI), while the detection limits (LODs) were 0.004 and 0.014 μg kg−1 for Cr(III) and Cr(VI), respectively. A total of 10 rice samples of different origin and colour (depending on the type of industrial processing) were analysed in this study. The content of Cr(VI) was below the limit of quantification in all of the rice samples analysed, while the Cr(III) levels ranged between 0.59 (whole grain rice) up to 104 µg kg−1 (brown rice). All samples were also analysed for their total Cr (Crtotal) content by ICP-MS solely and the results were in all cases comparable with the Cr(III) levels determined in the same samples. To assess the stability of Cr(III) and Cr(VI) in rice, one sample was spiked with Cr(III) and Cr(VI) (individually) at different levels (5.0, 10, 15 and 20 μg kg−1), held for 2 h, and then analysed by SS-ID HPLC-ICP-MS. The results showed a complete reduction of Cr(VI) to Cr(III), while Cr(III) remained stable at all spiking levels. These findings support the general statement from the European Food Safety Authority related to the complete absence of Cr(VI) in foods and confirms that Cr in rice is found solely as Cr(III) species. [ABSTRACT FROM AUTHOR]

The heteronemertean Cerebratulus marginatus Renier, 1804 is a well-known representative of the family Lineidae (Nemertea) inhabiting sandy or muddy sediments throughout the world. Due to its wide geographic distribution and the lack of distinctive external morphological features among different populations, the species has been considered cosmopolitan. Increasing evidence indicates that nemertean species, including Cerebratulus marginatus, described based on morphology are often not supported by genetic data and represent complexes of cryptic species, rather than cosmopolitan species. Here, we use species delimitation and phylogenetic analyses to evaluate the speciation patterns within the putative C. marginatus species complex. We examined 25 specimens morphologically ascribed to C. marginatus and closely related species using a multilocus dataset including two mitochondrial markers (16S rRNA, COI) and three nuclear markers (18S rRNA, 28S rRNA, H3). Our analyses identified at least four supported independent lineages among the populations analysed, indicating that samples identified as C. marginatus might represent indeed a complex of cryptic species. Therefore, our results do not support the cosmopolitanism of C. marginatus and provide additional evidence suggesting that species identifications in nemerteans should not be based exclusively on morphological or anatomical features which do not accurately reflect evolutionary patterns. Our study highlights the importance of including molecular data in addition to morphological information to accurately delimit species boundaries, thereby improving nemertean taxonomy by providing a more accurate picture of the true species diversity and geographic distribution of this typically neglected phylum. [ABSTRACT FROM AUTHOR]

A simple, sensitive and cost-effective homogeneous catalysis photochemical vapor generation (PVG) system for HPLC separation and atomic fluorescence spectrometry detection was reported herein for the speciation analysis of trace Se(IV) and Se(VI). Homogeneous Cd ions as a catalyst were stable and reliable, without complex nanomaterial synthesis and coating. Under the conditions of 60 μg mL−1 Cd ions, 3.5 m reaction coil, 40% acetic acid and 0.30 mL min−1 of 5 mM Na2CO3–1.3 mM NaHCO3, the online HPLC-Cd-PVG-AFS system enabled us to achieve a calculated detection limit of 0.16 and 0.21 ng mL−1 for Se(IV) and Se(VI), respectively. Moreover, it could also work successfully even in a phosphate separation system. Under the optimized conditions of 60 μg mL−1 Cd ions, 5 m reaction coil, 40% acetic acid and 0.35 mL min−1 of 50 mM Na2HPO3, a detection limit of 0.49/0.78 ng mL−1 for Se(IV)/Se(VI) was achieved. [ABSTRACT FROM AUTHOR]

Imperata is a ubiquitous grass genus of the tribe Andropogoneae (Poaceae), distributed throughout the world. Previous systematic studies had established that the genus encompasses nine species although no phylogenetic molecular studies are available in which all the taxa have been included. The American continent has the largest number of species, encouraging research into how these taxa have evolved. Here we present a phylogenetic analysis based on three plastids (ndhF, trnL-F, and atpB-rbcL) and one nuclear (ITS) marker that cover the most extensive geographic distribution of the genus. We use this phylogeny to test the monophyly of Imperata within tribe Andropogoneae, analyze the infrageneric relationships of the genus, and estimate lineage divergence time. Additionally, ecological niche models (ENM) of the American lineages are presented to recognize the abiotic factors that constraint their potential geographic distribution and allow an understanding of the ecological drivers for species diversification. Our results yield a fully supported tree where monophyly is confirmed for the genus and exposes the existence of two clades, one encompassing five American lineages and the other encompassing those of the rest of the world. In parallel, molecular dating, ENM, and ecological speciation tests suggest that American lineages underwent speciation during the Quaternary associated with conservatism and niche divergence. Our results contribute to both the taxonomic and to the evolutionary knowledge of grasses, and also to the understanding of the biological diversity in the Neotropics. [ABSTRACT FROM AUTHOR]

Solvent extraction of samarium from aqueous solutions by two different types of extractants, namely D2EHPA and PC88A, in kerosene was investigated. Through identification of speciation diagrams, the chemically stable complex of samarium in different acidic solutions (H2SO4, HCl and HNO3) were studied. Regarding the various types of samarium species in sulfate medium in comparison with other acidic environments, H2SO4 and HNO3 media were chosen to examine the extraction behavior of samarium complexes. Thermodynamic parameters of samarium extraction reactions by D2EHPA and PC88A from aqueous solutions of HNO3 and H2SO4 were calculated as ΔG°D2EHPA-HNO3, ΔG°D2EHPA-H2SO4, ΔG°PC88A-HNO3, ΔG°PC88A-H2SO4 equal to -5.58, 3.40, 6.70 and 14.26, and the corresponding ΔHº values were equal to -9.38, -2.75, 4.01 and 16.95 kJ/mol, respectively. According to the results, D2EHPA seemed to be a more efficient extractant than PC88A and nitric aqueous solution was a better media than the sulfuric type. The synergistic effect of binary extractants revealed that synergistic factors were 2.94 and 5.74 in sulfuric and nitric solutions, respectively, for a D2EHPA:PC88A ratio of 2:3. The compositions of extracted complexes by D2EHPA and PC88A in sulfuric and nitric solutions were SmH3A6 and SmH3B6, respectively. Thermodynamic parameters of extraction reactions were calculated as: Ke equal to 9.513, 0.254, 0.067, 0.003 and ΔS°D2EHPA-HNO3, ΔS°D2EHPA-H2SO4, ΔS°PC88A-HNO3, ΔS°PC88A-H2SO4 values were equal to -12.75, -20.64, -9.03, and 9.03 (J mol-1) respectively. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The objective of the present study was to investigate the impact of iron deficiency and iron replenishment on serum iron (Fe), copper (Cu), manganese (Mn), and zinc (Zn) speciation and tissue accumulation in a deferrioxamine-induced model of iron deficiency. A total of 26 male Wistar rats were divided into three groups: control; Fe-deficient; Fe-replenished (with iron (II) gluconate). Serum ferritin and transferrin levels were assessed using immunoturbudimetric method. Liver, spleen, and serum metal levels were assessed using ICP-MS. Speciation analysis was performed using a hyphenated HPLC-ICP-MS technique. Desferrioxamine injections resulted in a significant decrease in tissue iron content that was reversed by Fe supplementation. Iron speciation revealed a significant increase in serum transferrin-bound iron and reduced ferritin-bound Fe levels. Serum but not tissue Cu levels were characterized by a significant decrease in hypoferremic rats, whereas ceruloplasmin-bound fraction tended to increase. At the same time, Zn levels were found to be higher in liver, spleen, and serum of Fe-deficient rats with a predominant increase in low molecular weight fraction.Both iron-deficient and iron-replenished rats were characteirzed by increased transferrin-bound Mn levels and reduced low-molecular weight fraction. Hypothetically, these differences may be associated with impaired Fe metabolism under Fe-deficient conditions predisposing to impairment of essential metal handling. However, further studies aimed at assessment of the impact on Fe deficiency on metal metabolism are highly required. [ABSTRACT FROM AUTHOR]

The solidification/stabilization (S/S) method is a common technique for the remediation of soils polluted by heavy metal. This study, thus, evaluated the long-term effectiveness, in term of the stabilization of lead in the solidified/stabilized soils, under freeze-thaw cycles, which are important physical processes that lead to material weathering. Three types of compound binders were obtained by mixing the three most commonly used binders (cement, quicklime, and fly ash) in varying proportions for the remediation of lead-contaminated soils. The leachability, chemical forms, and microstructure characteristics of the solidified/stabilized samples after various numbers freeze-thaw cycles (i.e., 0, 30, 90, and 180 times) were examined by utilizing the toxicity characteristic leaching procedure (TCLP) test, chemical speciation analysis, and scanning electron microscopy (SEM). The results showed that the long-term freeze-thaw cycles lead to decreased leachate pH and increased lead concentration in the leachate. The larger the total mix quantities of cement and quicklime, the lower the concentration of lead was presented in the leachate, however, indicating that cement and quicklime are more effective in immobilizing lead ions than fly ash. Chemical speciation analysis revealed that the long-term freeze-thaw cycles did, however, reduce the content of carbonate-bound form lead while the quantity of the ion-exchange forms. SEM further confirmed the observed leaching characteristics and chemical speciation characteristics. In addition, it indicated that, at the same number of freeze-thaw cycles, high initial lead concentrations substantially delayed the hydration process of cement in solidified lead-contaminated soil. [ABSTRACT FROM AUTHOR]

BACKGROUND: Selenium is an essential micronutrient for humans. The spatial heterogeneity of selenium in soil is the main cause of various diseases and environmental problems. Selenium in soil is unevenly distributed across the globe, with most soils being low in selenium. Globally, the average selenium content in soil is 0. 4mglkg, while it is 346 - 2018mg/kg in typical high - selenium areas. Thus, accurate analysis of selenium in soil is of great significance in research on seleniferous soil. The reasonable use of reference materials can aid in the effective monitoring of the quality of analysis. OBJECTIVES : To summarize the status of research on selenium in soil, and the development of the corresponding analytical methods and reference materials. METHODS: This article describes the distribution characteristics, speciat10n, and migration and transformation characteristics of selenium in soil. Furthermore, the methods for extracting selenium speciation in soil, the progress of research on selenium content analysis technology, and the status of the development of soil selenium reference materials in recent years are summarized. RESULTS: Because of limited advancements m the development of analytical techniques, research on the mechanism of migration and transformation is still incomplete. The emergence of sequential extraction techniques provides a new way to study the distribution, migration, and transformation of soil selenium speciation. However, this method is still under development and has many shortcomings, such as inadequate selectivity and inevitable speciation transformation. Atomic fluorescence spectroscopy is the mainstream approach for the analysis of selenium content in soil, especially in China. Mass spectrometry, with high precision and a low detection limit, and synchrotron radiation X - ray technology, with in - situ speciation analysis capabilities, offer significant advantages in the analysis of trace and ultra - trace elements and speciation analysis. There is a significant gap in the research on reference materials with gradient content and certified speciation content. CONCLUSIONS: Methods with a low detection limit, high sensitivity, and matrix interference resistance are urgently needed. The combined application of sequential extraction, mass spectrometry, and X - ray fluorescence can promote research on selenium in soil. Moreover, related certified reference materials with gradient content and certified speciation content are in short supply. [ABSTRACT FROM AUTHOR]

This is the 13th Atomic Spectrometry Update (ASU) to focus on advances in elemental speciation and covers a period of approximately 12 months from December 2019. This ASU review deals with all aspects of the analytical atomic spectrometry speciation methods developed for: the determination of oxidation states, organometallic compounds, coordination compounds, metal and heteroatom-containing biomolecules, including metalloproteins, proteins, peptides and amino acids, and the use of metal-tagging to facilitate detection via atomic spectrometry. As with all ASU reviews, the focus of the research reviewed includes those methods that incorporate atomic spectrometry as the measurement technique. However, because speciation analysis is inherently focused on the relationship between the metal(loid) atom and the organic moiety it is bound to, or incorporated within, atomic spectrometry alone cannot be the sole analytical approach of interest. For this reason, molecular detection techniques are also included where they have provided a complementary approach to speciation analysis. This year the number of publications concerning As speciation remains similar to those covered last year, as do those for studies on Se speciation. The recent growth in work concerning Hg speciation has halted, although this is still a popular topic with the number of reports concerning Fe, halogen and sulfur speciation also rising. The number of elements covered this year reaches 30, showing the breadth of the elemental speciation field and how such work is now becoming more routine. [ABSTRACT FROM AUTHOR]

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Organoarsenic species in marine matrices have been studied for many years but knowledge gaps still exist. Most literature focuses on monitoring of arsenic (As) species using previously published methods based on anion- and cation-exchange high-performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS). These studies are often limited to few As species and/or only specific method performance characteristics are described. Most marine certified reference materials (CRMs) are only certified for arsenobetaine (AB) and dimethylarsinate (DMA), making it difficult to evaluate the accuracy of analytical methods for other organoarsenic species. To address these gaps, the main objective of this work was to develop and validate a method for speciation analysis of a broad range of organoarsenic species in marine matrices. Optimum extraction conditions were identified through a 27–3 fractional factorial design using blue mussel as test sample. The effects of sample weight, type and volume of extraction solution, addition of H2O2 to the extraction solution, extraction time and temperature, and use of ultrasonication were investigated. The highest As recoveries were obtained by using 0.2 g as sample weight, 5 mL of aqueous methanol (MeOH:H2O, 50% v/v) as extractant, extraction carried out at 90 °C for 30 min, and without ultrasonication. Anion- and cation-exchange HPLC-ICP-MS settings were subsequently optimized. The method detected a total of 33 known and unknown As species within a run time of 23 and 20 min for cation-exchange and anion-exchange, respectively. A single-laboratory validation was conducted using several marine CRMs: BCR 627 (tuna fish tissue), ERM-CE278k (mussel tissue), DORM-4 (fish protein), DOLT-5 (dogfish liver), SQID-1 (cuttlefish), TORT-3 (lobster hepatopancreas), and CRM 7405-b (hijiki seaweed). Method performance characteristics were evaluated based on selectivity, limits of detection and quantification, linearity, trueness, precision, and measurement uncertainty. This work proposes an extraction procedure which allowed satisfactory quantification of As species with low solvent and energy consumption, supporting "Green Chemistry" principles. The study also presents a new set of As speciation data, including methylated arsenic species and arsenosugars, in recently issued marine CRMs, which will be valuable for future speciation studies on As. This work is the first to report a total of 33 different As species in marine CRMs. [ABSTRACT FROM AUTHOR]

A method for simultaneous preconcentration and determination of mercury species in water and soil samples was established using high‐performance liquid chromatography with hydride generation atomic fluorescence spectrometry after ultrasound‐assisted dual‐cloud point extraction. The extraction process was divided into two steps. In the first cloud point extraction, inorganic mercury and methylmercury formed chelates with sodium diethyldithiocarbamate and were extracted into Triton X‐114 micelles. In the second stage, a displacement reaction between sodium diethyldithiocarbamate‐inorganic mercury/methylmercury and l‐cysteine occurred, and the analytes entered the l‐cysteine aqueous solution under ultrasonication. This aqueous solution was directly introduced to the high‐performance liquid chromatography with hydride generation atomic fluorescence spectrometry and the detection was completed within 6 min. Under the optimum experimental conditions, the linear range was 0.10–5.0 μg/L (r ≥0.9993) for inorganic mercury and methylmercury, and the enhancement factors were 15.7 for inorganic mercury and 6.35 for methylmercury. The limits of detection for inorganic mercury and methylmercury were 0.004 and 0.016 μg/L, respectively. The approach was successfully applied to the determination of trace inorganic mercury and methylmercury in water and soil samples with good recoveries (85.3–110%). This method solved the problem of peak fusion of the two analytes and was successfully applied to the speciation analysis of mercury. [ABSTRACT FROM AUTHOR]

This study investigated the mobility and availability of Cd, Pb, and As pollution in the sediments of the Xijiang River Basin, China. The speciation analysis and ecological risk assessment of Cd, Pb, As in 21 sediment samples from the Xijiang River basin were studied by the sequential extraction technique, the enrichment factor (EF), the geo-accumulation index (Igeo), the potential ecological risk index (RI), the potential ecological risk factor (Eri), the risk assessment code (RAC), and the modified potential ecological risk index (MRI) assessment method. Metal speciation analysis indicated that the exchangeable and carbonate fraction were the primary binding phase for Cd in the sediment. However, the residual fraction was the major host for Pb and As. The Cd, Pb, and As speciation were highly correlated with Mn, organic matter (OM), carbonate (Carb), and pH. The RAC and MRI results showed that the mobility and availability of Cd, Pb, and As in the sediment followed the order of Cd > As > Pb. The higher mobility of Cd posed an elevated environmental risk. Moreover, it was found that the Diaojiang River had high ecological risk levels. Principal component analysis (PCA) and redundancy analysis (RDA) revealed that the mining industry mainly contributed to the enrichment of Cd, Pb, and As. This study provides a better understanding to predict and possibly find ways to control pollution of Cd, Pb, and As in sediments of such basins. [ABSTRACT FROM AUTHOR]

Rapid and safe treatment of harvested fresh biomass of hyperaccumulators is essential for phytoremediation of metal-contaminated soils. Here, an electro-Fenton (EF) process was used to remove cadmium (Cd) and chemical oxidation demand (COD) from waste liquor from the dewatering of biomass of the hyperaccumulator Sedum plumbizincicola after flocculation precipitation. The results showed that the order of impact of the factors on the removal rate of COD and Cd was pH > electrical current density > H2O2 dosage. Increasing pH promoted Cd removal but hindered COD removal. As current density and H2O2 dosage increased the removal rates of both Cd and COD initially increased and then decreased. Compared to an electrocoagulation process, the addition of H2O2 in EF process greatly enhanced Cd and zinc (Zn) removal. Speciation analysis showed that most of the Cd and Zn in the initial liquor were organically and inorganically complexed. At optimal conditions, e.g., pH 5, current density 15 mA cm−2 and H2O2 dosage 9 g L−1, the removal efficiencies of Cd, Zn and COD reached 99.4, 99.9 and 55.5% after 80 min of EF treatment. Electro-Fenton process can therefore be used to quickly remove trace metals from the waste liquor of the hyperaccumulator. [ABSTRACT FROM AUTHOR]

We present a new autoclave that enables in situ characterization of hydrothermal fluids at high pressures and high temperatures at synchrotron x-ray radiation sources. The autoclave has been specifically designed to enable x-ray absorption spectroscopy in fluids with applications to mineral solubility and element speciation analysis in hydrothermal fluids in complex compositions. However, other applications, such as Raman spectroscopy, in high-pressure fluids are also possible with the autoclave. First experiments were run at pressures between 100 and 600 bars and at temperatures between 25 °C and 550 °C, and preliminary results on scheelite dissolution in fluids of different compositions show that the autoclave is well suited to study the behavior of ore-forming metals at P–T conditions relevant to the Earth's crust. [ABSTRACT FROM AUTHOR]

Time-dependent density functional theory (TD-DFT) and spectrophotometric methods were used for speciation analysis in systems disulfides (cystine, cystamine, homocystine, 3,3-dithiodipropionic acid) — [PdCl4]2− or [PtCl4]2−. We use the M06-2X and CAM-B3LYP density functionals with Def2-SVP basis set to reproduce the experimental UV-vis spectra; the polarized continuum solvation model (PCM) was fitted to take into account solvation effects of the medium (water). Used methods have shown the good agrees with the experiment — theoretical values of transition energies differ from real parameters within ±0.15 eV for functional CAM-B3LYP. Binuclear disulfide complexes of Pd(II) with cystine and cystamine have form S,N-coordination sites, instead of S,S-conformation. It was shown that Pd(II) thiolate complexes formed by cleavage of the disulfide bond exist as [PdCl3L] and [Pd2S2L2]. Pt(II)-disulfide systems have confirmed the presence of [Pt2Cl6(R-SS-R)] and [PtCl4(S-R)] complex species. The DFT/CAM-B3LYP/Def2-SVP/SMD level can be recommended for theoretical estimations of absorption spectra of complexes of palladium or platinum and sulfur-containing ligands. [ABSTRACT FROM AUTHOR]

The occurrence of 21 trace elements in native Mediterranean mussel (Mytilus galloprovincialis) from the Calich Lagoon, a typical brackish area of the northwest of Sardinia (Italy), was investigated. The seasonal variation of metals in bivalves was considered, and the highest values were found in spring and summer; in particular, a high significant (P < 0.001) temporal variation was reported for silver (Ag) and mercury (Hg). The highest and similar concentrations were registered for aluminium (Al, mean 32 mg kg−1wet weight), iron (Fe, mean 32 mg kg−1 w. w.), and zinc (Zn, mean 25 mg kg−1 w. w.). The maximum limits set by European Regulations for cadmium (Cd), mercury (Hg), and lead (Pb) were never exceeded. Speciation analysis revealed negligible risk related to inorganic arsenic (iAs). Therefore, M. galloprovincialis confirmed its role as suitable bioindicator to monitor the contamination of coastal environments. Although the recommended tolerable weekly intake (TWI) was not exceeded, the levels of aluminium should be carefully evaluated in monitoring plans in the studied lagoon. [ABSTRACT FROM AUTHOR]

Inductively coupled plasma mass spectrometry (ICP-MS) as a highly sensitive analytical technique has been widely used in the analysis of trace and ultra-trace inorganic elements, and its combination with chromatographic separation technology provides a powerful detection for element speciation analysis tool. This article describes the research progress of element speciation analysis using different ICP-MS combined technologies in recent years, including: (1) Gas Chromatography-Inductively Coupled Plasma Mass Spectrometry (GC-ICP-MS); (2) Capillary Electrophoresis-inductively coupled plasma mass spectrometry (CE-ICP-MS); (3) ion chromatography-inductively coupled plasma mass spectrometry (IC-ICP-MS); (4) high performance liquid chromatography-inductive coupling Plasma mass spectrometry technology (HPLC-ICP-MS). On this basis, the main research situation in the field of element speciation analysis in China is summarized, and the prospects for the development of element speciation analysis are prospected. Among these combined technologies, the sensitivity of GC-ICP-MS is high, and the sample transmission rate is close to 100%, but it is suitable for the separation of volatile or moderately volatile samples, and the application range is relatively narrow; the separation efficiency of CE-ICP-MS High, low consumption of samples and reagents, but limited by its injection volume, the lowest detection concentration is large; IC-ICP-MS mainly analyzes anions and cations and small molecule polar compounds, which is a useful supplement to liquid chromatography. The separation effect is good, fast and convenient, but the salts in the mobile phase of ion chromatography will cause the blockage of the ICP-MS injection tube and sampling cone, making the matrix effect serious; HPLC-ICP-MS is due to its wide range of applications and simplicity. The interface technology has become the most widely used combined technology in the study of element morphology analysis. This article believes that in the element speciation analysis research, the development of complex matrix sample pretreatment methods, the development of a series of element speciation analysis standard materials, and the establishment of multi-element speciation analysis methods are the development direction in the field of element speciation analysis. [ABSTRACT FROM AUTHOR]

A fast, efficient, and non-chromatographic method was presented in this study for nitrite, nitrate, and p-nitrophenol (N-compounds) extraction and speciation analysis of environmental samples. By applying ultrasound-assisted solid–liquid extraction (USLE), analytes were efficiently extracted from water, soil, or sediment collected in areas of environmental disaster. These analytes were selectively converted to NO(g) through UV photolysis (NO3−), H2O2/UV photocatalysis (PNP), and direct conversion (NO2−). Following conversion, NO(g) was separated from the liquid phase and determined by high-resolution continuum source molecular absorption spectrometry (HR-CS MAS). The LODs obtained were 0.097 ± 0.004 mg L−1 for nitrite, 0.119 ± 0.004 mg L−1 for nitrate, and 0.090 ± 0.006 mg L−1 for p-nitrophenol. On applying this speciation method to environmental samples, concentrations were found to be up to 0.99 ± 0.03 mg L−1 (NO2−), 49.80 ± 2.5 mg L−1 (NO3−), and 0.10 ± 0.02 mg L−1 (PNP). Finally, addition/recovery study of real water, soil, and sediment samples showed 101 ± 2% recovery for NO2−, 100 ± 1% for NO3−, and 96 ± 5% for PNP. [ABSTRACT FROM AUTHOR]

The protection of cultural relics in a chariot pit in the ancient ruins has become an important issue. In order to study the spatial distribution, speciation of heavy metals in soil at a cemetery where an ancient chariot was buried and the influence heavy metals have had on the cultural relics. Heavy metals in soil samples surrounding the cultural relic were analyzed via atomic absorption spectrometry (AAS) using a wet digestion method combined with a three-step sequential extraction procedure. Results for seven heavy metals (Cu, Pb, Zn, Cr, Fe, Mn and Sn) and the speciation of six heavy metals (Cu, Pb, Zn, Cr, Fe and Mn) indicated that their contents exceeded local soil background values, indicating that the soil around the site had been contaminated to a certain degree. Analysis of their speciation showed that Mn mainly existed in the form of a reducible fraction in the soil, while the other elements were mainly in the form of a residual fraction. Correlation analysis showed that, except for the HOAc soluble fraction, a significant positive correlation existed between the content of the different forms and their total amounts. Heavy metals present in the soil surrounding the ancient relic predominantly influence the relic due to their related chemical reactions. In particular, copper and iron have a significant influence on corrosion of the cultural relics in this chariot pit. [ABSTRACT FROM AUTHOR]

• One-pot hydrothermal strategy was used to prepared magnetic adsorbent. • The MNC contained abundant functional groups and presented good magnetic properties. • Multiple forces co-contributed to the capture of MNC/MSPE towards Se(IV)/OPA complex. • Sensitive and reliable method for the speciation of Se(IV) and Se(VI) was developed. Speciation of Se(IV) and Se(VI) is essential due to their significant differences in reactivity, toxicity and bioavailability. Efficient extraction is the pivotal step in the quantification of inorganic selenium species. In this work, a new magnetic nano-composite (MNC) containing boronic acid group and aminated multwalled carbon nanotubes was facilely fabricated by means of one-pot hydrothermal strategy. The prepared MNC contained abundant functional groups and satisfactory magnetic saturation value. Combining with magnetic solid phase extraction (MSPE) format, the MNC displayed satisfactory capture performance towards the complex formed by the coordination of Se(IV) and o -phenylenediamine (OPA). Adsorption isotherm and adsorption kinetics were studied in detail to investigate the adsorption procedure of Se(IV)/OPA complex on MNC. Under the optimal preparation conditions of MNC and extraction parameters, the MNC/MSPE was connected with HPLC equipped with a diode array detector (DAD) to quantify trace Se(IV) and Se(VI) species in water and milk samples. Se(VI) was reduced to Se(IV) and then the total inorganic Se was quantified by the developed method. Subtraction method was used to measure the concentration of Se(VI). The achieved limits of detection were in the ranges of 0.0082–0.013 μg/L and 0.041–0.13 μg/kg for water and milk samples, respectively. Recoveries in actual samples spiked with different amounts of analytes varied from 81.0 % and 117 %, and the RSDs for repeatability varied from 1.0 % to 10 %. In comparison with existing studies based on MSPE, the established method presents some merits such as greenness in the preparation of magnetic adsorbent, rapid extraction procedure, low cost and satisfactory sensitivity in the speciation of inorganic Se species. [ABSTRACT FROM AUTHOR]

[Display omitted] • A 2,3-diaminonaphthalene post-synthetic modified magnetic MOF was fabricated. • The material was applied to the selective extraction of inorganic selenium. • The material exhibited selectivity toward Se(IV) at a pH of 2.5. • LOD and linear range were 8.0 ng/L and 25–8000 ng/L, respectively. • The analytical applicability was confirmed in various food, and water samples. In this work, a 2,3-diaminonaphthalene post-synthetic modified magnetic metal–organic framework was fabricated for fast and selective determination of inorganic selenium in real food and water samples. The results exhibited that selenium (IV) is adsorbed by the nano-material at a pH of 2.5, and in this way, selenium (IV) can be quantified selectively. After identifying the nanosorbent with FT-IR, CHNS, XRD, SEM, TEM, VSM, and BET surface analysis, parameters affecting the retention and desorption were optimized. Under optimal conditions, the detection limit of 8 ng/L was achieved for selenium (IV), and the method's precisions were less than 12.5 % intra-day RSD% and < 14.4 % for inter-day RSD%. The highest adsorption capacity was obtained as 264 mg/g. Finally, the desired adsorbent was used to extract and determine selenium species in water samples and total selenium in food samples. One of the most important advantages of the present method is its speed, ease, time-saving, and high accuracy. [ABSTRACT FROM AUTHOR]

Mercury is a pervasive and concerning pollutant due to its toxicity, mobility, and tendency to biomagnify in aquatic and terrestrial ecosystems. Speciation analysis is crucial to assess exposure and risks associated with mercury, as different mercury species exhibit varying properties and toxicities. This study aimed at developing a selective detection method for organic mercury species in a non-invasive biomonitoring matrix like human hair. The method is based on frontal chromatography (FC) in combination with inductively coupled plasma mass spectrometry (ICP-MS), using a low pressure, homemade, anion exchange column inserted in a standard ICP-MS introduction system, without requiring high-performance liquid chromatography (HPLC) hyphenation. In addition to the extreme simplification and cost reduction of the chromatographic equipment, the proposed protocol involves a fast, streamlined and fully integrated sample preparation process (in contrast to existing methods): the optimized procedure features a 15-min ultrasonic assisted extraction procedure and 5 min analysis time. Consequently, up to 100 samples could be analyzed daily, making the method highly productive and suitable for large-scale screening programs in public and environmental health. Moreover, the optimized procedure enables a limit of detection (LOD) of 5.5 μg/kg for a 10 mg hair microsample. All these features undeniably demonstrate a significant advancement in routine biomonitoring practices. To provide additional evidence, the method was applied to forty-nine human hair samples from individuals with varying dietary habits successfully finding a clear correlation between methylmercury levels (ranging from 0.02 to 3.2 mg/kg) in hair and fish consumption, in line with previous literature data. [Display omitted] • A high throughput procedure for organomercury speciation in human hair is presented. • Fast extraction (15 min) and analysis (5 min) ensure a 100 samples/day capability. • Microsamples of 10 mg can be determined with LOD of 5.5 μg/kg. • The method was validated by a standard reference material of human hair. • Successful application to a local case study (49 samples). [ABSTRACT FROM AUTHOR]

The dominant species of vanadium (V) are V(IV) and V(V) which exhibit different toxicity and biological effects. Thus, speciation of V(IV) and V(V) is highly essential. Efficient sample preparation is the core step in the quantification of V(IV) and V(V). In the present study, a new task specific microextraction column based on monolith mingled with Fe 3 O 4 nanoparticles (MBMC) was in situ synthesized in capillary and utilized as the extraction phase of magnetic field-assisted in-tube solid phase microextraction (MA-IT-SPME) of V(IV) and V(V) species which were coordinated with ethylene diamine tetraacetic acid (EDTA). The prepared MBMC presented porous and superparamagnetic properties, and possessed abundant functional groups. Results revealed that the exertion of magnetic field during adsorption and eluting steps boosted the extraction efficiency of V(IV)-EDTA and V(V)-EDTA chelates from 65.1 % to 55.7 %–90.0 % and 80.1 %, respectively. Under the beneficial extraction parameters, the established MA-IT-SPME was online hyphenated with HPLC/DAD to perform speciation of trace vanadium in water and vegetable samples, the achieved limits of detection were 0.054–0.060 μg/L and 1.4–1.5 μg/kg in water and vegetable samples, respectively, and the spiked recoveries varied from 82.5 to 118 %. In addition, relevant extraction mechanism under magnetic field was explored. In comparison with existing methods, the developed MA-IT-SPME technique displays some attractive merits such as automation, good anti-interference ability, high extraction efficiency, low cost and less use of organic solvent, in the capture of V species. The established online MBMC@MA-IT-SPME-HPLC/DAD system can become a competitive approach for sensitive speciation of V(IV) and V(V) at trace levels in complex samples. [Display omitted] • A novel microextraction column for MA-IT-SPME was synthesized. • Application of magnetic field during extraction procedure improved the extraction efficiency. • Extraction conditions were optimized and extraction mechanism was deduced. • Online MBMC@MA-IT-SPME-HPLC/DAD was established for simultaneous analysis of V(IV) and V(V). [ABSTRACT FROM AUTHOR]

Ramie (Boehmeria nivea L.) is a promising phytoremediation candidate due to its high tolerance and enrichment capacity for antimony (Sb). However, challenges arise as Sb accumulated mainly in roots, complicating soil extraction. Under severe Sb contamination, the growth of ramie may be inhibited. Strategies are needed to enhance Sb accumulation in ramie's aboveground parts and improve tolerance to Sb stress. Considering the beneficial effects of selenium (Se) on plant growth and enhancing resistance to abiotic stresses, this study aimed to investigate the potential use of Se in enhancing Sb uptake by ramie. We investigated the effects of Se (0.5, 1, 2, 5, or 10 μM) on ramie growth, Sb uptake and speciation, antioxidant responses, and ionomic profiling in ramie under 10 mg/L of SbIII or antimonate (SbV) stresses. Results revealed that the addition of 0.5 μM Se significantly increased shoot biomass by 75.73% under SbIII stress but showed minimal effects on shoot and root length in both SbIII and SbV treatments. Under SbIII stress, 2 μM Se significantly enhanced Sb concentrations by 48.42% in roots and 62.88% in leaves. In the case of SbV exposure, 10 μM Se increased Sb content in roots by 42.57%, and 1 μM Se led to a 91.74% increase in leaves. The speciation analysis suggested that Se promoted the oxidation of SbIII to less toxic SbV to mitigate Sb toxicity. Additionally, Se addition effectively minimized the excess reactive oxygen species produced by Sb exposure, with the lowest malondialdehyde (MDA) content at 0.5 μM Se under SbIII and 2 μM Se under SbV, by activating antioxidant enzymes including superoxide dismutase, catalase, peroxidase, and glutathione peroxidase. Ionomic analysis revealed that Se helped in maintaining the homeostasis of certain nutrient elements, including magnesium, potassium (K), calcium (Ca), iron (Fe), and copper (Cu) in the SbIII-treated roots and K and manganese (Mg) in the SbV-treated roots. The results suggest that low concentrations of Se can be employed to enhance the phytoremediation of Sb-contaminated soils using ramie. [Display omitted] • Se effectively mitigated Sb-induced ramie biomass inhibition. • Se enhanced Sb uptake in ramie and facilitated the conversion of SbIII to less toxic SbV. • Se upregulated SOD, CAT, POD, and GPX to counteract excessive ROS generated by Sb. • Se contributed to maintaining the homeostasis of Mg, K, Ca, Fe, Cu, and Mn. • Se dosage should be optimized for maximum effect as it is dose-dependent. [ABSTRACT FROM AUTHOR]

Dimethylsilanediol (DMSD) is the degradation product of methylsiloxane polymers and oligomers such as volatile cyclic methylsiloxanes (cVMS). To better understand the environmental fate of this key degradation product, we conducted a three-part study on the movement of DMSD in soil. The objective of this third and final study was to determine the fate of DMSD in soil-plant systems under constant irrigation. Soil columns were constructed using two soils with the upper 20 cm layers spiked with 14C-labeled DMSD. Corn seedlings were transplanted into the soil columns and placed in a field plot underneath a transparent cover that prevented rainwater from reaching the soil columns while allowing soil water to be volatilized freely. The soil-plant columns were regularly irrigated with known amounts of DMSD-free plant growth solution to sustain the plant growth. At pre-determined time intervals (15–67 days), the plant and soil columns were sectioned and the distribution of 14Corganosilicon species in the soil profile and plant parts was determined using a combination of Liquid Scintillation Counting and High-Performance Liquid Chromatography-Flow Scintillation Analysis, while soil water loss was determined gravimetrically. It was found that the majority (>92 %) of DMSD initially spiked into the soil was removed from the soil-plant systems. Although DMSD was transported from the soil to the plant, it was subsequently volatilized from the plant via transpiration, with only a small fraction (∼5%) remaining at the conclusion of the experiments. In addition, little non-extractable DMSD was found in the top layer of soil in the soil-plant systems, suggesting that the air-drying of soil is a necessary pre-condition for the formation of such non-extractable silanol residue on topsoil. [Display omitted] • In the presence of plants, DMSD is found to be removed from irrigated soil via evapotranspiration process. • In contrast with bare soil, little non-extractable DMSD is found in the surface soil layer. • At any given time, only a small amount of the total spiked DMSD was found in plants. • DMSD concentration in the plant was found to decrease exponentially as the plant grew. • Speciation analysis suggests that most of DMSD was volatilized as DMSD. [ABSTRACT FROM AUTHOR]

The ability of an organism to biomethylate toxic inorganic arsenic (As) determines both, the amount of As available for uptake higher up the food chain and the toxicity of bioavailable As. An exposure study was conducted to determine ability of farmed crickets to metabolize dietary arsenate. Crickets were exposed to 1.3 ± 0.1, 5.1 ± 2.5 and 36.3 ± 5.6 mg kg−1 dietary arsenate and quantitation of total As showed retention of 0.416 ± 0.003, 1.3 ± 0.04 and 2.46 ± 0.09 mg kg−1, respectively. Speciation analysis revealed that crickets have well developed ability to biomethylate dietary arsenate and the most abundant methylated As compound was DMA followed by MMA, TMAO and an unknown compound. Arsenobetaine, although present in all feed, control and As-rich, was measured only in the control crickets. To assess the bio-accessibility of the As species, crickets were subjected to simulated gastrointestinal digestion. The results showed that majority of As was extracted in saliva, followed by gastric and intestinal juice, which mass fraction was equal to residue. Over 78% of total As was shown to be bio-accessible with methylated species reaching 100% and iAs over 79% bio-accessibility. Additionally, arsenite and arsenate have shown different distributions between sequential leachate solutions. Bioaccumulation of As was observed in the studied crickets although it does not seem to occur to the same extent at higher exposure levels. [Display omitted] • Field crickets can metabolize dietary arsenate. • As Bioaccumulation factor decreased with increased exposure level. • AsBet measured in all feed and control crickets but not in the exposed crickets. • ≥ 80% of total As in exposed crickets is bio-accessible. • The major fraction of bio-accessible As is the most toxic inorganic As. [ABSTRACT FROM AUTHOR]

Sulfide mineral reactivity and dissolved sulfur (S) speciation in tailings systems remain poorly constrained across redox gradients, especially in heterogeneous materials. We characterized the S-bearing mineralogy, prevailing geochemical conditions, and dissolved, intermediate (incompletely oxidized) S speciation, at three legacy tailings in Ontario and two in Nova Scotia, Canada. Tailings in Cobalt, Ontario, contained up to 3.5 wt-% sulfide minerals, mainly authigenic chalcopyrite and cobaltite/gersdorfitte. Sulfate (up to 537 ppm) dominated dissolved S in surface and porewaters from these sites, but significant fractions of thiosulfate and tetrathionate, at >40% of total S, could be detected in tailings porewaters. Tailings at the Goldenville and Montague sites in Nova Scotia contained up to 7.5 wt-% sulfide minerals, mainly pyrite and arsenopyrite, but contained smaller fractions of intermediate S (<15% on average, mostly thiosulfate and sulfite). Across all sites, overlying surface waters contained both lower total S levels, as well as lower intermediate-S fractions, than tailings porewaters. Redox conditions appeared to exert a dominant control on aqueous S speciation, and correlations of intermediate S with dissolved Fe levels and tailings mineralogy suggested the latter presented lesser influences on S dynamics. This work demonstrates that incomplete S oxidation and resultant intermediate S species play an important role for S mobility in sub-oxic tailings systems and at legacy mine sites and should therefore be considered in long-term reactivity and water quality predictions. [Display omitted] • Analysis of mineralogy and aqueous S species in >50 samples from 5 tailings sites. • Intermediate, non-sulfate S occurred in sub-oxic conditions at up to 73% of total S. • Low-Fe porewater had largest non-sulfate S fractions; oxic surface waters smallest. • Diagenetic sulfide precipitation likely decreased intermediate S mobility at depth. [ABSTRACT FROM AUTHOR]

Imitation milks based on vegetables have become relevant in recent years as a substitute for cow´s milk. Total and inorganic content of arsenic (As) determination in food is of utmost importance due to toxicological concerns. This study aimed to (1) optimize and validate a methodology for speciation analysis using anion exchange high performance liquid chromatography coupled to plasma mass spectrometry and (2) analyze the arsenic content in milk and imitation milks. Determination of As (III) and As (V) was done following a simple and innovative treatment, which consisted on the dilution of a small volume of sample in mobile phase and further filtration. Furthermore, acid microdigestion for total As determination with small amounts of acid and sample was optimized. The detection limits of the method ranged from 0.2 to 0.7 µg L−1. Regarding to arsenic content we found that imitation milks based on peanuts and nuts presented the lowest inorganic As content (between 1.7 and 1 µg L−1) whereas the highest values were found in imitations based on soy, rice and vetch (27.3, 13 and 8 µg L−1, respectively). The cow's milk presented intermediate levels of inorganic As (4 µg L−1). Also, almond- and quinoa-based imitation milks showed inorganic As values below detection limits, so these imitation milks may be the safest to consume with respect to arsenic content. • Speciation analysis of arsenic in milk and imitation milks. • Acid microdigestion of samples using small volumes of sample and reagents. • Comparison of inorganic As in imitation milks. • Simple and fast sample pretreatment for chromatographic analysis. [ABSTRACT FROM AUTHOR]