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The oxidative dissolution of sulfide minerals consumes oxygen and can generate redox gradients in mine wastes that affect the mobility of redox-sensitive solutes. However, the controls of oxygen depletion on sulfide reactivity and sulfur mobilization remain poorly constrained, complicating the long-term assessment of drainage quality dynamics. We investigated pyrite and Fe-rich sphalerite weathering using aqueous S speciation and quantitative mineralogical analyses under controlled, ambient versus sub-oxic, conditions at 6 < pH < 9. Titration assays revealed that oxidation rates for pyrite (up to 10−10 mol m−2 s−1) were higher than for sphalerite (up to 10−11 mol m−2 s−1) and, for both minerals, decreased by two orders-of-magnitude under sub-oxic (<50 ppm O 2) conditions. Precipitation of secondary S-bearing minerals was restricted to elemental S, with no sulfate- or thiosulfate-salts detectable >0.01 wt%. Sulfate was the dominant aqueous S species produced in all experiments, but significant amounts of thiosulfate, tetrathionate, and sulfite were also found. These dissolved intermediate S species were abundant under both sub-oxic and oxic conditions, and broadly in line with known sulfide oxidation mechanisms, even though the weathering of pyrite produced several factors less incompletely oxidized S than that of sphalerite, under otherwise comparable conditions. This work shows that a range of intermediate S species may be produced even in low-reactivity conditions and may help optimize the management of such mine waste materials. [Display omitted] • Controlled weathering of Fe-rich sphalerite and pyrite under geochemical gradients. • Sulfide oxidation rates decrease by >2 orders-of-magnitude under oxygen limitation. • Formation of dissolved intermediate S species is mineral- and redox-dependent. • Negligible precipitation of incompletely oxidized S phases under studied conditions. [ABSTRACT FROM AUTHOR]

Environmental impacts caused by mining activities (mainly tailings and effluents) are presenting serious challenges for humanity worldwide. In Brazil, clay extraction activities in the Ceramic District of Santa Gertrudes (CDSG) have led to the formation of abandoned drainage wells causing environmental and human health concerns. In the 90's, it was discovered that in one of the production areas, known as the region of the lakes of Santa Gertrudes, several ceramic industries had contaminated lakes created by abandoned clay pits with industrial effluents containing toxic metals. In the present study, analysis of total and dissolved concentrations of Al, Cd, Co, Cu, Mn, Ni, Pb and Zn in the waters of these lakes were combined with the diffusive gradients in thin films (DGT) technique to assess the lability and bioavailability of the target elements, representing one of the first studies to investigate the real environmental impact of contamination caused by ceramic production wastes to an aquatic system. Furthermore, based on the total concentrations and main physicochemical characteristics of each lake, a speciation analysis was performed using the MINTEQ software which data was compared with other surface water systems. The results indicated the presence of metals associated with ceramic residues in total, dissolved and labile fractions. It was verified that Zn, Ni and Cu were the only target metals found in labile form and according to speciation were present in the form of "free" ions, and thus may present risk in terms of bioavailability, although the majority of the total concentrations are within the limits established by the national environmental agency. [Display omitted] • Water samples from the lakes of Santa Gertrudes Ceramic Pole were analyzed. • The total and dissolved (filtered) content of metals was evaluated. • Concentration of Al, Mn, Zn, Co, Cu, Cd, Ni and Pb were measured by ICP-MS. • DGT technique was used to evaluate the lability of the elements. • Speciation analysis was performed using MINTEQ software. [ABSTRACT FROM AUTHOR]

• Efficient large-scale use of low silicon-aluminum tailings for geopolymerization at ambient temperature. • Increased slag content enhances gel polymerization and get a compact structure dominated by C-(A)-S-H gel with higher polymerization degree and better bonding. • Higher metakaolin content intensifies zeolite phase formation and shows a non-homogeneous structure dominated by low Na/Si ratios N-A-S-H gels with weak bonding. • Facilitation of tailings dissolution and gel polymerization by raising alkali concentration. • Promising curing properties for lead (97%) and zinc (91%) in geopolymer pastes. This study delves into the effective utilization of low silicon–aluminum tailings, exploring their potential for large-scale applications in one-part ('just add water') geopolymers. Optimizing the raw material composition and alkali content is crucial. Higher slag content enhanced gel production and polymerization, resulting in a more homogeneous structure dominated by C-(A)-S-H gels with stronger bonding. While increased metakaolin content forms more zeolite phases and exhibited an incompatible structure filled with N-A-S-H gels with weaker bonding. Alkali concentrations also play a significant role in promoting tailings dissolution and gel polymerization. Excessive levels, however, hinder the process and restrict strength development. Ultimately, a reasonable mechanical strength of 52.8 MPa was achieved. The geopolymer paste effectively immobilizes Pb and Zn, demonstrating impressive immobilization rates of 97% and 91%, respectively. The chemical speciation analysis reveals the conversion from unstable to stable state. These findings highlight the potential applicability of low silicon–aluminum tailings in geopolymers. [ABSTRACT FROM AUTHOR]

The electroplating process of copper pyrophosphate (Cu 2 P 2 O 7 ) results in the production of a large volume of wastewater that contains a high concentration of copper (Cu). Currently, conventional lime precipitation creates a substantial amount of secondary pollution, which adds extra economic and environmental burdens. In this study, we suggest a straightforward method for on-site recovery of Cu from Cu 2 P 2 O 7 electroplating wastewater. By optimizing various parameters, characterizing the resulting product, assessing its electroplating capabilities, and analyzing the speciation during the reaction, we comprehensively investigated the feasibility and mechanism of this technique. The results demonstrated that, under the optimal conditions (Cu/P molar ratio of 0.96, pH of 5.0, and a reaction time of 5.0 min), the concentration of residual Cu remained stable between 22.2 and 27.7 mg/L, even when the initial Cu concentrations varied. The addition of Cu triggered a series of hydrolysis and ionization reactions, primarily leading to the formation of Cu 2 P 2 O 7 ·3H 2 O. The harvested Cu 2 P 2 O 7 ·3H 2 O proved to be suitable for practical electroplating applications, exhibiting comparable performance to commercially available Cu 2 P 2 O 7 ·3H 2 O. This demonstrates the feasibility of recovering high-purity Cu 2 P 2 O 7 ·3H 2 O from copper electroplating wastewater, offering a promising approach for on-site copper reuse and concurrently reducing the demand for natural copper resources. Furthermore, this approach significantly reduces the generation of solid waste, aligning with the principles of sustainable development., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The production of selenium-enriched fish can contribute to alleviating selenium deficiency in human diets. However, it is still unclear which selenium source, as an additive, can efficiently and cost-effectively produce high-quality selenium-enriched fish. This study evaluated the effects of selenium nanoparticles (SeNP), selenite, and selenomethionine (SeMet) on the growth, antioxidant capacity, selenium content, selenium speciation, and meat quality of grass carp. Ten diets were prepared, including a basal diet (BD) and three concentrations (0.1, 0.3, and 0.9 mg/kg) of SeNP, selenite, and SeMet. A total of 600 fish (250.79 ± 1.57 g) were randomly assigned to 30 tanks (3 tanks/group). Fish were fed the experimental diet three times daily for 60 d. In this study, SeNP most significantly promoted the growth and antioxidant capacity of grass carp, with 0.3 mg/kg SeNP identified as the optimal additive concentration. Additionally, SeNP demonstrated equally excellent bioavailability as SeMet and significantly increased the content of SeMet in grass carp ( Ctenopharyngodon idella ) muscle. Furthermore, compared to SeMet and selenite, dietary SeNP could more significantly enhance the content of selenocysteine (SeCys 2 ) and methylselenocysteine (MeSeCys) in grass carp muscle tissue. In addition, we have demonstrated that SeCys 2 and MeSeCys promote apoptosis of cancer cells (HeLa) through the mitochondrial apoptotic pathway (involving Bax and Bcl-2). Furthermore, as an additive, 0.3 mg/kg SeNP significantly improved the flesh quality of grass carp by reducing crude fat and heavy metal content, as well as increasing the levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and the ratio of n-3/n-6 polyunsaturated fatty acid (PUFA). In summary, SeNP is the most suitable additive for producing selenium-enriched fish., Competing Interests: We declare that we have no financial and personal relationships with other people or organizations that can inappropriately influence our work, and there is no professional or other personal interest of any nature or kind in any product, service and/or company that could be construed as influencing the content of this paper., (© 2024 The Authors.)

The redistribution and transformation of arsenic (As) during the Fe(II)-catalyzed transformation of As-adsorbed ferrihydrite remains unclear. This study investigated the re-crystallization process and products of As-adsorbed ferrihydrite accelerated by Fe(II) and the fate of arsenate and arsenite at pH 7 under anaerobic condition. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), and synchrotron based X-ray absorption near edge structure (XANES) were utilized for the As and Fe speciation analysis. Results showed that both As(V) and As(III) can retard the transformation of ferrihydrite. The concentration and speciation of As strongly influenced the mineralogy and morphology of produced crystalline Fe oxyhydroxides. The higher As(V) loading (Fe/As = 40–100) resulted in the conversion of most ferrihydrite to lepidocrocite instead of goethite. The adsorbed As(III) showed weak effect on the re-crystallization of ferrihydrite at the early stage. A considerable fraction of As(III) (70–80%) was oxidized to As(V) during the Fe(II) catalyzed transformation of As(III)-adsorbed ferrihydrite. The oxidation of As(III) to As(V) in turn retarded the transformation of the remaining ferrihydrite to goethite and induced the production of a small amount of lepidocrocite. A temporary release of As(V) was observed during the first 5 days and the released As(V) was re-adsorbed back to the crystalline products, whereas no As was released to the aqueous phase in the As(III)-ferrihydrite systems. During the re-crystallization of ferrihydrite, 1 M phosphate-extractable As decreased quickly by up to 90% in the solid phase, indicating that partial As transformed to more stable phase. Our results suggested that Fe(II)-catalytic transformation of As-adsorbed ferrihydrite could help reducing the mobility and toxicity of As in anoxic aquifers. Unlabelled Image • Concentration and speciation of As influence transformation of ferrihydrite. • More than 80% of As(III) is oxidized to As(V) by Fe(II)-activated ferrihydrite. • Considerable fraction of adsorbed As transformed to phosphate-unextractable phase. [ABSTRACT FROM AUTHOR]

The crucial point of this study was to verify the hypothesis that both thallium species are not affected by the procedure of photolysis when it is applied as a method of simplification of sample matrix containing surfactants, and that this method of sample pretreatment leads to reliable results of Tl speciation analysis. It is important especially because of high instability of Tl(III), which makes partial reduction of Tl(III)DTPA complex unavoidable. After conservation of Tl speciation by addition of DTPA the photolysis assisted with nanostructured hierarchically organized film was performed using "solar lamp" (Fe 2 O 3 /WO 3 /Fe 2 O 3 film, pH 6, 380–800 nm). The results imply that under proposed photolysis conditions Tl(I) is not oxidized in the presence of water matrix, SDS nor DTPA. Also, even 100-fold excess of Fe(III) ions over Tl(I) ions does not accelerate the oxidation of Tl(I) to Tl(III), and already 2 h of heterogeneous photolysis allow to limit the interferences caused by SDS and obtain reliable results. The data obtained by anodic stripping voltammetry (ASV) were verified using an inter-method comparison with SEC ICP MS. Moreover, after 2 h irradiation the reduction rate of Tl(III)DTPA standard solution increased only slightly from 2-3% to 4–6%. The presence of river water matrix causes a slightly higher (9%) reduction of the trivalent form. These changes are irrelevant in the context of instability of Tl(III) compounds. This study indicates that "soft decomposition" can be applied in speciation analysis of thallium in water matrix. Image 1 • Mineralization assisted with photocatalysts does not disrupt Tl speciation analysis. • Nano-semiconductors support decomposition of surfactants in water. • ASV serves as a "sensor" to non-complete organic matter simplification. • DTPA and Fe(III) ions do not accelerate the oxidation of Tl(I) during photolysis. • Photocatalysis assisted with solar light is a suitable water pretreatment. [ABSTRACT FROM AUTHOR]

Speciation and isotopic analyses of mercury (Hg) detected at high concentration (11–107 mg total Hg/kg) in the hair samples of Pakistani subjects were carried out to analyze whether the source of Hg was the skin cream or the soap they used. Liquid chromatography-ICP mass spectrometric speciation analysis revealed that the Hg in the hair was primarily inorganic. This result supported our assumption that skin care products were the source of the high concentration of Hg in hair, which was based on the statistical association found in our previous study because it is known that inorganic Hg compounds are added to some skin care products sold in some countries. Stable isotope ratios of the Hg in the hair samples of 6 subjects and 3 skin cream samples, which were reported to be used by the subjects, were measured by multi-collector ICP mass spectrometry after acid digestion. A comparison of the isotopic compositions of Hg in hair and skin cream in two subjects revealed that the composition in both samples matched in one subject, hence confirming that the products were the source of high Hg concentration in hair. However, the isotopic compositions of Hg in hair and skin cream did not match in the other subject demonstrating the presence of other exposure source(s). • Speciation and isotope ratios of mercury detected high concentration in hair were analyzed. • Mercury in the hair samples was mostly inorganic and methymercury was negligible. • High level of Hg was detected in some of the skin lightning creams the subjects used. • Isotopic ratios of hair and skin creams were consistent in one subject but not in the other. [ABSTRACT FROM AUTHOR]

This study concerns total arsenic (TAs) and arsenic species determination in three species of mushrooms collected in Yunnan, China. The purpose of this study was to check concentration level of arsenic in Boletus edulis , Tricholoma matsutake and Suillellus luridus , estimate arsenic bioaccessibility and find out which arsenic species occur in mushrooms to assess if they may pose a threat to human health. An analytical methodology based on ion chromatography (IC) hyphenated to inductively coupled plasma mass spectrometry (ICP-MS) with dynamic reaction cell (DRC) and size exclusion chromatography (SEC) with UV–Vis detection and ICP-DRC-MS detection. Ultrasound assisted extraction (UAE), microwave assisted extraction (MAE) and enzymatic assisted extraction (EAE) were applied. Quantification of As species in extracts was performed by IC/ICP-DRC-MS in the first dimension. Slightly better extraction efficiencies were obtained for MAE (from 75% to 90%) then for UAE. EAE was used for estimation of bioaccessibility by application of a modified BARGE bioaccessibility method (UBM) for in vitro studies. Bioaccessibility values were in the ranges of 73%–102%, 74%–115% and 18%–87% for step 1 (S1), for step 2 (S2) and for step 3 (S3) of EAE, respectively. Extracts obtained after EAE were subjected to SEC-UV-Vis/ICP-DRC-MS analysis as the second dimension. The main signal was obtained in the area of a molecular mass of ∼5 kDa for all mushroom extracts. Monitoring of an 50SO+ ion confirmed that this signal comes from As-protein. In sample of Boletus edulis additional signal occurred which is classified as unknown As-compound. Both signals require identification with another analytical technique. Image 1 • Speciation of As in mushroom samples from Yunnan, China. • Speciation analysis by IEC-ICP-DRC-MS and SEC-UV-Vis/ICP-DRC-MS. • Ultrasound, microwave and enzymatic assisted extraction of arsenic from mushroom samples. • Bioaccessibility of As from mushroom samples using modified BARGE method. [ABSTRACT FROM AUTHOR]

• 31 interfaces are compared for the coupling of LC and ICP-MS/MS. • The extra-column variance varies from 6 to 8000 μL² depending on the interface. • Solute dispersion is proved to be a major issue for most commercial interfaces. • The effect of flow-rate and spray chamber temperature is highlighted. Liquid chromatography (LC) coupled with a specific detection such as inductively coupled plasma-mass spectrometry (ICP-MS/MS) is a technique of choice for elementary speciation analysis for complex matrices. The analysis of organic matrices requires the introduction of volatile solvents into the plasma which is an analytical challenge for this coupling technique. Detection sensitivity can be significantly affected by instrumental limitations. Among those, we were interested in the solute dispersion into the interface located between LC and ICP-MS/MS. This interface consists in both a Sample Introduction System (SIS) and a possible flow splitter. This study, divided into two parts, investigated the analytical performance (in terms of sensitivity and efficiency) generated by the coupling of LC and ICP-MS in the specific case of organic matrices. In Part I [ 1 ], we previously discussed the impact of extra column dispersion on the performance of LC-ICP-MS, first from a theoretical point of view and next, by assessing extra-column dispersion in 55 published studies on LC-ICP-MS. It was shown that SIS was rarely optimized with respect to its contribution to extra-column band broadening. The critical impact of flow splitting on extra-column dispersion was also pointed out. The present Part II is dedicated to the experimental comparison of commercially available SIS by assessing extra-column band broadening and hence the contribution of SIS to the loss in both efficiency and sensitivity. It is shown that the peak variance, due to SIS, can vary from 10 to 8000 μL² depending on the combination of both nebulizer and spray chamber. Whereas the highest values (i.e. > 2000 μL²) are much too high in high performance liquid chromatography (HPLC), even the lowest values (i.e. < 100 μL²) can be inappropriate in ultra-high pressure liquid chromatography (UHPLC) as highlighted in this study. In light of these results, it appears that nebulizer and spray chamber have to be chosen together with respect to the chromatographic technique (HPLC or UHPLC) and that both peak dispersion and peak intensity depend on key parameters including SIS device geometry, flow rate entering the interface or spray chamber temperature. [ABSTRACT FROM AUTHOR]

A novel Sr2+ fluorescent probe, N-(2-hydroxy-3-(1H-benzimidazol-2-yl)-phenyl)-1-aza-18-crown-6-ether (BIC), was synthesized and its fluorescence properties, equilibria, and local structure in solution were studied in detail. The fluorescence intensity of BIC in DMSO was enhanced selectively upon addition of Sr2+ but not Na+, K+, Mg2+, Ca2+, and Ba2+. To employ this rather hydrophobic BIC probe in aqueous media, a sodium laurate (LaNa) micellar solution was used as a good solvent. The detection limit of said LaNa micelle-BIC system (2.02 μM) is lower than that of the H2O system (309 μM), but higher than that of the DMSO system (0.04 μM). Therefore, it is clear that the LaNa micelles have an effect on the detection of Sr2+ by BIC in aqueous solutions. Further structural studies by extended X-ray absorption fine structure and speciation analyses revealed that BIC undergoes complexation equilibria corresponding to the formation of [Sr(BIC)]+ species in all solution types. It was concluded that the changes in the Sr2+-BIC fluorescence in solution are attributed to the formation of such [Sr(BIC)]+ complexes. [ABSTRACT FROM AUTHOR]

[Objective] Correlations between contents of heavy metals and sediments properties were analyzed. Speciation character and the bioavailability of heavy metals were discussed based on the rations secondary phase and primary phase(RSP) and potential ecological risk assessment. [Method]Taking the mangrove wetland sediments of Qinglan Harbor wetland in Hainan as the research object, speciation and contents of four heavy metals(Cu, Zn, Cd and Pb)in sediments of mangrove wetland were treated by BCR sequential extraction procedure. [Result] Between heavy metals it had different degrees of correlation and exhibited significantly positive correlation between Cd and Pb, suggesting that the pollution of Cd and Pb resulted from homologous pollutants. Cu and Cd were mainly in the acid soluble-extractable fraction;Pb was mainly in the reducible fraction;Zn was dominated by residual fraction;It showed that Cu, Cd and Zn in the sediments of the study area had serious potential hazards. There was significant correlation between the forms of Cd, Cu, Zn and PB of heavy metals in sediments. Contents of Cu and Cd existed as weak acid soluble fraction and oxide fraction exhibits significantly positive correlation with pH, indicating that sediments pH had a certain impact on chemical speciation of heavy metals. [Conclusion] These 4 kinds of heavy metals in the sediments have high bioactive state, and have strong biological activity, which are easy to be absorbed and used by plants. Cd, Cu, Zn and Pb have higher risk of release in the sediments of the research area, which should be paid enough attention. [ABSTRACT FROM AUTHOR]

Driven by the significant need for characterization of the chemical speciation of arsenic in food, this work developed a method for rapid determination of four common arsenic species, namely, arsenite, arsenate, monomethyl arsenic acid, and dimethyl arsenic acid, in vegetables using microwave‐assisted extraction, followed by detection with high‐performance liquid chromatography hyphenated to inductively coupled plasma‐mass spectrometry. Initial screening results showed that microwave‐assisted extraction using 1% HNO3 exhibited the highest overall efficiencies for all arsenic species without causing significant degradation of the organic ones. With the aid of response surface methodology, the optimum conditions established for extraction of arsenic species from vegetables were: 500 mg of freeze‐dried vegetable sample, extracted by closed vessel microwave‐assisted extraction using 10 mL of 2% v/v HNO3 at 90°C for 17 min. Application of the method in the analysis of 24 market vegetable samples indicates that the extraction efficiencies for total arsenic species were in the range of 91.4–106%. Arsenite and arsenate were found to be the predominant arsenic species in the vegetables, which suggests that vegetable consumption could be an important route of inorganic arsenic exposure for the population with a heavy vegetable diet in arsenic polluted regions. [ABSTRACT FROM AUTHOR]

• HPLC ICP-MS and HPLC NAA have been applied in arsenic speciation analysis. • For As, HPLC NAA gives results with better accuracy than HPLC ICP-MS. • HPLC NAA could be complementary to HPLC ICP-MS in the speciation analysis. • HPLC NAA is valuable analytical tool in QC/QA in the speciation analysis. Arsenic and its inorganic species: As (III), As (V), dimethylarsenic acid (DMA) and monomethylarsenic acid (MMA) were determined in hypoallergenic formulas and grain porridges commercially available on Polish market, dedicated for infant 0–8 months. After quantitative extraction with 0.5% HNO 3 , separation of individual species was performed by high performance liquid chromatography (HPLC), and their determination by neutron activation analysis (NAA) and inductively coupled plasma mass spectrometry (ICP-MS). Due to relatively low content of As in the analysed samples, it was only possible to determine DMA using the HPLC-ICP-MS mode. HPLC separation coupled with off-line determination by NAA enabled the determination of more extracted As species (especially inorganic) with good accuracy. Certified reference material (CRM) Rice Flour SRM 1568b (NIST) was used for the validation of both procedures. [ABSTRACT FROM AUTHOR]

The idea that populations must be geographically isolated (allopatric) to evolve into separate species has persisted for a long time. It is now clear that new species can also diverge despite ongoing genetic exchange, but few accepted cases of speciation in sympatry have held up when scrutinized using modern approaches. Here, we examined evidence for speciation of the Howea palms of Lord Howe Island, Australia, in light of new genomic data. We used coalescence‐based demographic models combined with double digest restriction site associated DNA sequencing of multiple individuals and provide support for previous claims by Savolainen et al. that speciation in Howea did occur in the face of gene flow. [ABSTRACT FROM AUTHOR]

• Selenoneine attenuates the induction of reactive species in Caenorhabditis elegans. • Ameliorative effect does not occur immediately, but 48 h post-treatment. • Significant uptake of selenoneine, but no metabolism and retention in the worms. • Possible involvement of molecular mechanisms with delayed consequences. Selenoneine (2-selenyl-N α , N α , N α -trimethyl-L-histidine), the selenium (Se) analogue of the ubiquitous thiol compound and putative antioxidant ergothioneine, is the major organic selenium species in several marine fish species. Although its antioxidant efficacy has been proposed, selenoneine has been poorly characterized, preventing conclusions on its possible beneficial health effects. Treatment of Caenorhabditis elegans (C. elegans) with selenoneine for 18 h attenuated the induction of reactive oxygen and nitrogen species (RONS). However, the effect was not immediate, occurring 48 h post-treatment. Total Se and Se speciation analysis revealed that selenoneine was efficiently taken up and present in its original form directly after treatment, with no metabolic transformations observed. 48 h post-treatment, total Se in worms was slightly higher compared to controls and no selenoneine could be detected. The protective effect of selenoneine may not be attributed to the presence of the compound itself, but rather to the activation of molecular mechanisms with consequences at more protracted time points. [ABSTRACT FROM AUTHOR]

We investigated sulphate application, different statuses of soil microbial activity and their joint effects as variables associated with changes in potentially plant-available selenium (Seppa) and soil Se fractionation during the course of an incubation study. The time-resolved behaviour of added selenate (400 µg Se/kg as Na2SeO4) in two agricultural soils was elucidated by means of single extraction (50 mmol/L NH4H2PO4), sequential extraction procedure (SEP) and chemical speciation analysis in phosphate extracts. The decrease in phosphate-extractable Se, a consequence of soil aging, was inhibited by sulphate (by 34% and 29% in Chernozem and Cambisol, respectively) and by gamma-irradiation (by 46% and 20% in Chernozem and Cambisol, respectively) after 72 days of incubation as compared to the control treatments. Glucose amendment dramatically decreased Seppa only in the Chernozem. After 1 year, the initial soil treatment with respect to inhibited or stimulated microbially-mediated processes substantially controlled the distribution pattern of exogenous Se as observed using the SEP. Application of sulphur fertilisers and sources of labile organic matter is thus an essential agronomic practice to correct unfavourable amounts of Seppa. [ABSTRACT FROM AUTHOR]

Sedimentary redox proxies are usually employed to reconstruct the paleo-redox conditions of bottom water environments, assuming that porewater and bottom water dissolved oxygen concentrations are similar. Using a combination of geochemical and magnetic techniques, we investigate the relationship between iron speciation and mineralogy in recent (~1760–2009 CE) sediments retrieved from the Santa Barbara Basin (SBB) – a modern silled basin with low-oxygen (dissolved O 2 < 10 μmol/kg) and sporadically anoxic (no O 2 detected) bottom waters. Magnetic analyses reveal that biogenic magnetite is preserved in SBB sulfidic porewaters on at least decadal to centennial time scales. Highly-reactive Fe (oxyhydr)oxides remain preserved despite observed sulfidic porewaters, indicating incomplete pyrite conversion, and producing low Fe py [pyrite Fe]/Fe HR ratios. We attribute this observation to restricted porewater reaction kinetics under high sedimentation rates. Our results also reveal non-steady state diagenesis caused by instantaneous depositional events (e.g., turbidites and flood layers). The most reducing water column suggested by Fe speciation coincided with the Macoma layer, where in situ colonization of hypoxia-intolerant bivalve shells argues for the most oxygenated bottom water in the 250 year record. A turbidite potentially introduced fresh unsulfidized Fe HR that buffered upward-diffusing sulfide from underlying sediments. Subsequent pyrite precipitation following re-establishment of sulfidic porewaters could have facilitated a "false positive" interpretation. In comparison, redox-sensitive metal enrichments (Mo EF , U EF , and Re EF) were not obscured by post-depositional diagenesis and appear to accurately record redox geochemistry at the sediment-water interface. • Fe (oxyhydr)oxides preserved in SBB sulfidic porewaters on centennial timescales. • Incomplete pyrite conversion in sulfidic porewaters due to rapid burial leads to low Fe py /Fe HR. • Non-steady state diagenesis can overprint redox signals in Fe speciation. • Trace metal enrichments controlled by redox conditions at sediment water interface were not overprinted in SBB. [ABSTRACT FROM AUTHOR]

Cerium oxide nanoparticles (CeO2NPs), used in some diesel fuel additives to improve fuel combustion efficiency and exhaust filter operation, have been detected in ambient air and concerns have been raised about their potential human health impact. The majority of CeO2NP inhalation studies undertaken to date have used aerosol particles of larger sizes than the evidence suggests are emitted from vehicles using such fuel additives. Hence, the objective of this study was to investigate the effects of inhaled CeO2NP aerosols of a more environmentally relevant size, utilizing a combination of methods, including untargeted multi-omics to enable the broadest possible survey of molecular responses and synchrotron X-ray spectroscopy to investigate cerium speciation. Male Sprague–Dawley rats were exposed by nose-only inhalation to aerosolized CeO2NPs (mass concentration 1.8 mg/m3, aerosol count median diameter 40 nm) for 3 h/d for 4 d/week, for 1 or 2 weeks and sacrificed at 3 and 7 d post-exposure. Markers of inflammation changed significantly in a dose- and time-dependent manner, which, combined with results from lung histopathology and gene expression analyses suggest an inflammatory response greater than that seen in studies using micron-sized ceria aerosols. Lipidomics of lung tissue revealed changes to minor lipid species, implying specific rather than general cellular effects. Cerium speciation analysis indicated a change in Ce3+/Ce4+ ratio within lung tissue. Collectively, these results in conjunction with earlier studies emphasize the importance of aerosol particle size on toxicity determination. Furthermore, the limited effect resolution within 7 d suggested the possibility of longer-term effects. [ABSTRACT FROM AUTHOR]

Graphical abstract Thiol-functionalized nano-SiO 2 can effectively reduce the toxicity of heavy metal ions in soil. Highlights • SiO 2 –SH was used to passivate heavy metal ions in contaminated soil. • The speciation transformation of Ni, Cu and Zn was inferred. • The passivation process could be described by Webber-Morris equation. • Ni, Cu and Zn mainly interacted with –SH on SiO 2 –SH. Abstract Different speciation of heavy metal ions has different toxicity level. The different speciation contents can be used as an important basis to evaluate the passivation efficiency of passivator. In this study, Ni2+, Cu2+ and Zn2+ in soil was passivated with thiol-functionalized nano-silica by solidification/stabilization technology, and the behavior of heavy metal ions in soil were explored. The result shows that, passivation time, soil moisture and passivator dosage can influence the toxicity of heavy metal ions via changing the speciation of metal ions. Passivation time and passivator dosage will promote passivation efficiency, while too low or too high soil moisture are not conducive to the passivation. The change of soil moisture will affect the surface charge distribution of soil and passivator, thus influence the migration of metal ions. According to speciation analysis, four kinds of speciation could be transferred reciprocally and the transformation will cause impact on the toxicity of heavy metal ions in soil. We explained the behavior of different metal ions based on the percentage of various speciation of heavy metal ions and inferred the transformation process of such metal ions in the passivation process. At the same time, based on Webber-Morris equation, the kinetic process during passivation process was discussed. [ABSTRACT FROM AUTHOR]

In this work, a novel carboxyl-functionalized organic–inorganic hybrid monolithic column (TMOS-co-CES) was prepared via one-pot co-condensation of carboxyethylsilanetriol sodium salt (CES) and tetramethoxysilane (TMOS). The TMOS-co-CES monolithic column was used as a needle-solid phase microextraction (SPME) matrix followed by using an inductively coupled plasma mass spectrometer (ICP-MS) for simultaneous speciation analysis of inorganic chromium and antimony. Various parameters of SPME operation and analytical performance were investigated systematically. Under the optimum conditions, the TMOS-co-CES column can selectively adsorb low-valent chromium (Cr(III)) and antimony (Sb(III)) without adsorbing high-valent species (Cr(VI) and Sb(V)) over a wide pH range (4.0–9.0). In the elution step, the captured Cr(III) and Sb(III) can be substantially completely eluted using 10% nitric acid (v/v) as the eluent. The TMOS-co-CES monolithic column based SPME protocol has the merits of facile preparation, low cost, selective adsorption and high adsorption capacity. In addition, the TMOS-co-CES column operates under milder elution conditions, offers higher recovery for antimony species, and is more compatible with the ICP-MS instrument, compared with a previously reported thiol-functionalized hybrid monolithic column taking speciation analysis of antimony as an example. Therefore, the developed TMOS-co-CES monolithic column is more suitable than the thiol-functionalized monolithic column for the speciation analysis of chromium and antimony in environmental waters. [ABSTRACT FROM AUTHOR]

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The immobilization effect and mechanism of nano-hydroxyapatite(NHAP) on Pb in the ryegrass rhizosphere soil were studied by root-bag experiment. The speciation analysis results revealed that the residual Pb concentrations in the rhizosphere soil significantly increased after NHAP application. The acid-soluble and reducible Pb concentrations significantly decreased, indicating that NHAP had obviously immobilized Pb. Meanwhile, NHAP significantly promoted the secretion of tartaric acid from ryegrass roots, resulting the rhizosphere soil pH had been below that of the control group. This helped to relieve the stress of Pb on ryegrass, also promoted the dissolution of NHAP, resulting the formation of stable precipitation with more Pb ions. NHAP increased the rhizosphere soil pH by 0.03 to 0.17, which promoted the conversion of Pb to non-utilizable bioavailability. The total Pb mass balance indicated only a very small proportion Pb transferred to the shoots through ryegrass roots. The formation of pyromorphite by Pband NHAP in soil was accordingly to interpret the dominant mechanism for Pb immobilization. [ABSTRACT FROM AUTHOR]

In this work, fast sequential determination and chemical speciation analysis of inorganic arsenic and antimony in airborne particulate matter collected in outdoor and indoor environments using slurry sampling and detection by hydride generation atomic absorption spectrometry (HG-AAS) is proposed. A Doehlert design was applied to optimise the hydride generation conditions of As and Sb for fast sequential determination in the same aliquot of particulate matter samples after preparation of the slurry. The limits of quantification (LoQ) obtained for As and Sb were 0.3 and 0.9 ng m−3, respectively. The accuracy of the analytical method was confirmed by analysis of the certified reference material of urban particulate matter (SRM NIST 1648a), presenting concordance with certified values of 92.7±7.7% for As and 91.2±9.5% for Sb. Precision was expressed as relative standard deviation (% RSD, n=3), with our results presenting values better than 3.4% and 4.2% for total inorganic As and Sb, respectively. For all analysed samples, total As concentrations and its inorganic species were below the LoQ of the analytical method (<0.3 ng m−3). However, the averages of total inorganic Sb concentrations in airborne particulate matter, collected as total suspended outdoor particles (TSPoutdoor), inhalable particulate matter (PM10), and total suspended indoor particles (TSPindoor), were 3.1±0.5, 2.4±0.6, and 2.6±0.4 ng m−3, respectively. Trivalent Sb (Sb3+) was the predominant inorganic species in all samples investigated, with mean percentages of 76%, 72%, and 73% in TSPoutdoor, PM10, and TSPindoor, respectively. The presence of Sb and its predominant inorganic form (Sb3+) can be attributed to vehicular traffic close to the sampled urban areas. Therefore, fast sequential determination of As and Sb and their inorganic species in particulate matter samples prepared as slurry by FS-HG-AAS is an efficient, accurate, and precise method and can be successfully applied to routine analysis. [ABSTRACT FROM AUTHOR]

• A simple and robust HPLC-HG-AFS method was developed and validated to quantify the levels of arsenic species (AsIII, MMAV, DMAV and AsV) in urine samples from 66 APL patients. • DMAV and un-metabolized AsIII were dominant arsenic compounds excreted from urine of APL patient treated ATO. MMAV and DMAV are considered the end products of arsenic metabolism. • Good positive correlations were found between arsenic species levels in urine and those in plasma. Urinary arsenic can reflect the levels of arsenic in plasma. Arsenic trioxide [As 2 O 3 , arsenite (AsIII) in solution] has been applied successfully for the treatment of acute promyelocytic leukemia (APL). The arsenic speciation analysis of urine is critical to reveal the metabolic mechanism and the relationship between arsenic species and the clinical response. To characterize the arsenic species in urine, a simple and robust HPLC-HG-AFS method was developed and validated to quantify the levels of arsenic species [AsIII and its metabolites, monomethylarsonic acid (MMAV), dimethylarsinic acid (DMAV), and arsenate (AsV)] in urine samples from 66 patients with APL. Patients received As 2 O 3 (0.16 mg/kg/day) via continuous slow-rate infusion or conventional infusion. Urine samples were collected at steady state before the start of the next daily administration. The relative proportions (median) of arsenic species in urine were: AsIII, 33.00% (IQR: 24.34%–46.82%); DMAV, 36.42% (IQR: 25.82%–51.98%); MMAV, 23.89% (IQR: 19.52%–27.19%); and AsV, 2.22% (IQR: 1.293%–3.665%). The levels and proportions of arsenic species vary widely among individual patients. DMAV and un-metabolized AsIII were the dominant arsenic compounds excreted from the urine of patients with APL treated with As 2 O 3. AsV was the least abundant arsenic species in all urine samples. Good positive correlations were found between the levels and proportions of arsenic species in urine and those in plasma; thus, urinary arsenic can reflect the levels of arsenic in plasma. Urinary arsenic is a critical biomarker to evaluate the metabolism and toxicity of arsenic in the clinical application of As 2 O 3. [ABSTRACT FROM AUTHOR]

Abstract Windowsill particulate matter (PM) samples were collected from an area near large lead-smelting facilities in Jiyuan (JP), the urban area of Jiyuan (JU) and the peri-urban area of Mianchi (MC) in Henan, China to investigate the concentration and inhalation bioaccessibility of Cd, Cu, Pb and Zn. The <10 μm portions of the samples were extracted with simulated lung fluid to assess the in vitro inhalation bioaccessibility. Lower concentrations of heavy metals were found in the MC samples than in the JP and the JU samples. The average concentrations of Pb, Cd and Cu in the portions of the same size are in the order of JP samples > JU samples > MC samples. For Pb, Cd and Zn, the maximum inhalation bioaccessibility fraction values are all found in the MC samples, which ranged 3.87–8.79%, while those of the JP and the JU samples are <2%. The Pb speciation analysis with X-ray absorption spectrometry indicate mineral bound Pb, PbS and Pb 3 (PO 4) 2 are the predominant Pb species in the JP samples; for the JU sample, organic bound Pb is the predominant Pb species in the 45–125 μm portion, while mineral bound Pb is the predominant Pb species in the 10–45 μm portion; for the MC samples, organic bound Pb is the predominant Pb species, followed by PbS. The results indicate that there is significant accumulation of Pb, Cd, Cu and Zn associated with PM in the area near the lead smelter and in the urban area of Jiyuan, especially Pb and Cd, however, the inhalation bioaccessibility of these metals in samples from the lead smelting impacted area is low, this may be due to the higher proportion of less soluble species of the metals in the samples from this area. However, organic matter bound Pb found in some samples has higher bioaccessibility than other Pb species. Graphical abstract Image 1 Highlights • High concentrations of Pb and Cd were found in PM affected by lead smelting. • Pb and Cd in PMs affected by lead smelting have low bioaccessibility. • Predominant Pb species differs in PMs from smelting affected and peri-urban areas. • Interaction between soil and PMs may elevate the bioaccessibility of metals. [ABSTRACT FROM AUTHOR]

The later Cambrian Steptoean Positive Carbon Isotope Excursion (SPICE) event was an episode marked by pronounced changes to the global biogeochemical cycles of carbon and sulfur and significant extinctions on several paleocontinents including Laurentia (North America). While the exact cause(s) of these events remains debated, various lines of evidence suggest an increase in the areal extent of anoxia at the seafloor was a likely feature. Here, we explore whether changes in local oxygenation accompanied the onset of the SPICE in southern Laurentia using cores of the Nolichucky and Eau Claire Formations from Ohio and Kentucky, USA, that represent a transect into the Rome Trough/Conasauga intrashelf basin. At our study locations, the initial positive δ13C shift of the SPICE occurs in conjunction with increases in the abundance and δ34S of sedimentary pyrite. Further local redox conditions, tracked using iron speciation analysis, indicate anoxic conditions developed at the two proximal locations after the start of the paired isotopic excursions. However, the location near the basin center shows no indication for anoxia before or during the onset of the SPICE. While this signal may reflect the structure of local redox conditions within the basin, with the development of anoxia limited to the basin margins, we argue that authigenic iron enrichments were muted by sedimentary dilution and/or the enhanced authigenesis of iron‐bearing sheet silicates near the basin center, masking the signal for anoxia there. Regardless of the areal extent of anoxia within the basin, in either scenario the timing of the development of anoxic bottom waters was concurrent with local faunal turnover, features broadly consistent with a global expansion of anoxia playing a role in driving the isotopic trends and extinctions observed during the event. [ABSTRACT FROM AUTHOR]

Iron (Fe) plays an important role within environmental systems. Synchrotron‐based X‐ray approaches, including X‐ray absorption spectroscopy (XAS), provide powerful tools for in situ analyses of Fe speciation, but beam damage during analysis may alter Fe speciation during its measurement. XAS was used to examine whether experimental conditions affect the analysis of Fe speciation in plant tissues. Even when analyzed in a cryostat at 12 K, it was found that FeIII can rapidly (within 0.5–1 min) photoreduce to FeII, although the magnitude of photoreduction varied depending upon the hydration of the sample, the coordination chemistry of the Fe, as well as other properties. For example, photoreduction of FeIII was considerably higher for aqueous standard compounds than for hydrated plant‐root tissues. The use of freeze‐dried samples in the cryostat (12 K) markedly reduced the magnitude of this FeIII photoreduction, and there was no evidence that the freeze‐drying process itself resulted in experimental artefacts under the current experimental conditions, such as through the oxidation of FeII, although some comparatively small differences were observed when comparing spectra of hydrated and freeze‐dried FeII compounds. The results of this study have demonstrated that FeIII photoreduction can occur during X‐ray analysis, and provides suitable conditions to preserve Fe speciation to minimize the extent of beam damage when analyzing environmental samples. All studies utilizing XAS are encouraged to include a preliminary experiment to determine if beam damage is occurring, and, where appropriate, to take the necessary steps (such as freeze drying) to overcome these issues. [ABSTRACT FROM AUTHOR]

Abstract Multi-elemental speciation analysis in a single run reduces costs, waste and time, and also sample consumption, which is favorable to a large set of instable samples. This work demonstrates mercury and arsenic speciation in a single run using high performance liquid chromatography with inductively coupled plasma mass spectrometric detection (HPLC/ICP-MS). Thiol compounds in mobile phases interfered with the elution of arsenite because of coordination action, which was overcome by gradient elution (elution of As(III) by thiol-free mobile phases at first). Four arsenic forms (As(III), DMA, MMA and As(V)) and three mercury species (Hg(II), MeHg and EtHg) were separated and detected by HPLC/ICP-MS using 4 mM tetrabutylammonium hydroxide (TBAH) (pH 6.0) in the first 1.0 min and 4 mM TBAH + 20 mM L -cysteine (pH 6.0) in the next 9.0 min. The detection limits were obtained at 0.078 for As(III), 0.081 for DMA, 0.078 for MMA and 0.15 μg L−1 for As(V), and 0.016 for Hg(II), 0.027 for MeHg and 0.032 μg L−1 for EtHg, and the reproducibilities (50 μg L−1 for each As-species and 10 μg L−1 for each Hg-species) were all lower than 3.7%. The proposed method was successfully applied for speciation analyses of arsenic and mercury in five lotus roots, which indicated DMA (3.5–7.9 μg kg−1) as the only arsenic species and MeHg (0.6–1.0 μg kg−1) as the only mercury species. Analyses of two certified reference materials demonstrated good agreement between determined values and certified values. All results prove its advantages including high sensitivity and high analytical efficiency, which are beneficial for routine speciation analyses of arsenic and mercury in a single run in environmental and food fields. Graphic Abstract fx1 Highlights • Speciation of arsenic and mercury was analyzed by HPLC-ICP-MS in one run. • Interference of Cys on the elution of As(III) was eliminated by gradient elution. • Four As species and three Hg species were simultaneously eluted within 10 min. • Arsenic and mercury speciation in lotus root was analyzed in one run. • DMA and MeHg were the only arsenic and mercury form in lotus root. [ABSTRACT FROM AUTHOR]

This paper describes an ion chromatography (IC) inductively coupled plasma mass spectrometry (ICP-MS) method, coupled with ultrasonic nebulization, for the speciation analysis of sulfur-namely sulfite (SO 3 2−), sulfate (SO 4 2−), and thiosulfate (S 2 O 3 2−). These ionic sulfur compounds were separated well within 4.5 min through IC when using a Hamilton PRP-X100 column as the stationary phase and a mobile phase comprising 60 mmol L−1 NH 4 NO 3 and 0.1% (v /v) formaldehyde solution (pH 7.0). The analyses were performed using a dynamic reaction cell (DRC) ICP-MS system. The sulfur-selective chromatogram was recorded at m / z 48, representing the 32S16O+ ion, formed through reactions with O 2 in the reaction cell. This approach of detecting 32S+ as its oxide ion 32S16O+ at m / z 48 avoided the effect of polyatomic isobaric interference towards the signal of 32S+ at m / z 32 caused by the ions 16O16O+ and 14N18O+. The limits of detection of the various species were in the range from 3.1 to 3.7 ng S mL−1(6.2 to 7.4 mg kg−1). Accuracy of the method was verified by comparing the sums of the concentrations of the individual sulfur compounds, as measured using this new procedure, with the total concentrations of sulfur in a standard reference material (NIST 1573a Tomato Leaves) and in several samples of dry foods purchased locally. After ultrasonication for 90 min, the sulfur species had leached quantitatively from the leaves and the dry foods into the mobile phase solution. The extraction efficiency was >95%. The spike recoveries of the various studied compounds ranged from 96 to 102%. Unlabelled Image • Speciation of sulfite, sulfate, thiosulfate in dry food. • Leaching of sulfur species from dry food by ultra sonication. • Ion chromatographic separation of sulfur species by Hamilton PRP-X100 column. • Determination of sulfur using DRC-ICP-MS at m / z 48 as 32S16O+. • Improved sensitivity using ultrasonic nebulization in ICP-MS. [ABSTRACT FROM AUTHOR]

This is the 11th Atomic Spectrometry Update (ASU) to focus on advances in elemental speciation and covers a period of approximately 12 months from December 2017. 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. The review does not cover fractionation, which is sometimes termed operationally defined speciation. 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. Therefore, molecular detection techniques are also included where they have provided a complementary approach to speciation analysis. As in previous years, As speciation continues to dominate the current literature with a significant number of publications concerning Hg and Se speciation and 'biomolecules', in which category a number of papers covered in the Se section could also belong. The number of elements covered in these updates also continues to rise with the speciation analysis of over 20 elements reported this year. [ABSTRACT FROM AUTHOR]

A sensitive and interference-free iodine speciation analysis in high salt matrix is crucial either for the application of iodine ion-exchange adsorption removal or in chlor-alkali industrial of caustic soda. In this study, we investigated the iodine speciation using the high performance liquid chromatography (HPLC) coupled with inductively coupled plasma mass spectrometry (ICP-MS). Peak splitting under high salt matrix was found and solved using the new efficient mobile phase of ammonium carbonate. A high-efficiency separation anion-exchange column (Dionex IonPac AS-14) for iodate and iodide with 100 mM (NH4)2CO3 solution at pH = 10 as mobile phase was confirmed, and the total running time of individual sample was within 8 min. Linear standard calibration plots were obtained in a concentration range of 1.0–100 μg L−1 for both iodate and iodide, and the detection limits were 0.05 μg L−1 for the former and 0.20 μg L−1 for the latter. A precise analytical procedure of HPLC-ICP-MS was developed to rapidly and exactly determine the iodine species of iodide and iodate at trace levels in high salt brine samples. [ABSTRACT FROM AUTHOR]

In this study, an artificial wetland filler matrix capable of effectively fixing phosphorus was prepared using a non-combustion process to save energy. To evaluate the adsorption performance of this filler, adsorption experiments were performed and the phosphorus adsorption mechanism characterization was studied. An alkaline environment was found to be conducive to the increase of adsorption capacity, but excessive alkalinity was not conducive to adsorption. Static adsorption experiments showed that the phosphorus removal rate could reach 95% in the simulated phosphorus-containing wastewater after adsorption completion. The adsorption process is closely simulated by the pseudo-second-kinetic adsorption model. The isothermal adsorption experiment data were consistent with the Langmuir and the Freundlich adsorption isotherms. The characterization results showed a large number of micropores and adsorption binding sites inside and on the surface of the filler. Speciation analysis on the adsorbed phosphorus revealed that chemisorption by calcium in this filler was the dominant adsorption mechanism. The research results of this study provide the basis and reference for the development of high-efficiency phosphorus removal filler in constructed wetlands. [ABSTRACT FROM AUTHOR]

In this study, a simple, pH-controlled, and natural deep eutectic solvent-based microextraction (NADES-ME) procedure is proposed before the spectrophotometric analysis of methylmercury (MeHg) and total mercury in fish and environmental waters. The method is based on charge-transfer sensitive ion-pair formation between MeHg and 3-(dimethylamino)-7-(methylamino)phenothiazin-5-ium chloride (Azure B – AzB) in the presence of chelating citrate-phosphate buffer at pH 6.0, and then extraction of the formed ion-pair complex with the NADES. The important variables affecting extraction efficiency were evaluated and optimised. At optimal conditions (300 µL of 1.0 × 10−3 mol L−1 AzB, 600 µL NADES (betaine-sorbitol, 1:3) containing 10% water (v/v) as extractant, 375 µL acetonitrile as aprotic solvent for sonication of 7 min at power of 300 W/40 kHz, and centrifugation at 4000 rpm for 3 min, respectively), the figures of merit for MeHg include a good linearity in the concentration range of 0.7–340 µg L−1, limits of detection and quantification of 0.25 and 0.83 µg L−1, and pre-concentration and sensitivity enhancement factors of 120 and 95, respectively. Figures of merit for total Hg (iHg, where Hg22+ ions are predominantly present in natural oxygen-rich waters such as freshwaters and seawater as well as elemental Hg and Hg2+ ions at very low amounts) after pre-oxidation at pH 5.0 include linearity range of 3–270 µg L−1 with limits of detection and quantification of 0.92 and 3.10 µg L−1, and pre-concentration and sensitivity enhancement factors of 120 and 35, respectively. The reliability (with recovery of 92–98.7% and RSD of 1.9–5.5%) was statistically validated by analysis of two standard reference materials (SRMs) with and without spiking. The method was successfully applied to the speciation analysis of total Hg, iHg and MeHg in fish and environmental waters. [ABSTRACT FROM AUTHOR]

A sensitive and accurate simultaneous continuous analysis for six arsenic species including arsenobetaine (AsB), arsenocholine (AsC), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), arsenite (AsIII), and arsenate (AsV) has been developed by high performance liquid chromatography with inductively coupled plasma mass spectrometry (HPLC-ICP-MS). An anion-exchange column of Hamilton PRP-X100 (Switzerland) was applied for separation of the six arsenic species with gradient elution of 1.25 mmol/L Na2HPO4 and 11.0 mmol/L KH2PO4 as the mobile phase A and 2.5 mmol/L Na2HPO4 and 22.0 mmol/L KH2PO4 as the mobile phase B. The linearity ranges for AsB, AsC, MMA, DMA, AsIII, and AsV were between 0.5 and 50.0 μg/L, and the detection limits of the six arsenic species were all within 0.01–0.35 ng/L. The relative standard deviations (RSDs) were within 2.26–3.68% and the recovery rates of samples ranged from 95 to 103%. The proposed method was applied for the arsenic speciation analysis of sediment pore-water samples, which were taken from the supernatant after centrifugation and filtration. [ABSTRACT FROM AUTHOR]

The stability of water films has been the focus of many researchers in the recent decades. Unfortunately, there is no consensus on the stability of these foam films or on the mechanisms responsible for stabilizing water films. This paper examines the reported results on this matter and scrutinizes them based on speciation analysis of the dissolved species and the recent achievements in the adsorption of inorganic ions on the air/water interface. Our results confirm the key role of surface contamination, interface approach velocity and evaporation in the drainage and lifetime of these water films. It confirms the stabilizing effect of contamination and the destabilizing effect of air-water interface approach velocity. Moreover, the negative sign of the surface/zeta potential of the air/water interface and its dependence on the pH value were explained. Interferogram of foam film of distilled water. Unlabelled Image • Speciation analysis of fresh DI and distilled water, and degassed DI water • Experimental data on the negative electrical charge of air bubbles and thin foam films from DI or distilled water • Theoretical proof of the negative charge of the air bubbles and thin foam films • Controversial experimental data on the drainage and stability of foam films from DI and distilled water • Criterion for validity of the experimental data [ABSTRACT FROM AUTHOR]

Reference measurements for methyl mercury in four new type of environmental matrix-matching certified reference materials (CRMs) were performed and values of methyl mercury mass fractions were assigned. Hyphenated technique high-performance liquid chromatography (HPLC) and inductively coupled plasma mass spectrometry (ICP-MS) was applied. To ensure the highest metrological quality, species-specific isotope dilution mass spectrometry (SS-IDMS) as primary method of measurements was evaluated. SI-traceable and accurate reference measurements of methyl mercury contents in environmental origin materials: river bottom sediment (M-2 BotSed), herring tissue (M-3 HerTis), cormorant tissue (M-4 CormTis) and codfish tissue (M-5 CodTis) are straightforward related to units of the mol and the kilogram. Results for MeHg (as Hg) obtained by two pair of isotopes: n(200Hg)/n(201Hg) ratio and n(202Hg)/n(201Hg) ratio, excellent agreed within calculated expanded uncertainty and were found to be (as Hg) (C ± U C (U C %)): (15.6 ± 1.0) μg kg−1 (6.4%) in M-2 BotSed, (216 ± 6) μg kg−1 (2.8%) in M-3 HerTis, (2106 ± 54) μg kg−1 (2.6%) in M-4 CormTis and (294 ± 8) μg kg−1 (2.7%) in M-5 CodTis. These data are particularly important in point of speciation analysis requirements, due to high toxicity of methyl mercury and its harmful effects on human health and entire ecosystem. Moreover, as there is still a noticeable lack of CRMs, it is necessary to introduce matrix-matching CRMs related to methyl mercury content in environmental samples for the quality control, monitoring study and risks assessment. As fishes and cormorant are bioindicators of methyl mercury contamination and sediments are pollution indicators, assigned reference values in appropriate CRMs provide unique matrix fit for the research purpose • Reference values of methyl mercury contents in environmental CRMs of unique matrices for speciation analysis were assigned. • Species-specific isotope dilution mass spectrometry as a primary method of measurements was evaluated. • HPLC for mercury species separation was applied to overcome the problem with artificial mercury formation. • Method validation and traceability of obtained values for methyl mercury to the system of reference SI was demonstrated. [ABSTRACT FROM AUTHOR]

A nondestructive method for speciation of sulphur (S), elemental sulphur and sulphate; and determination of total sulphur in mineral supplements for cattle by wavelength dispersive X-ray fluorescence (WD-XRF) spectrometry is proposed. Using direct solids analysis it was possible to perform S speciation with high analytical frequency, simplicity and precision. The intensities ratio for the different electronic transitions (S Kα 1,2 , S Kβ and S Kβ′) and principal component analysis (PCA) of the spectra obtained for samples and standards of different inorganic species of S allowed the speciation and quantification of S in mineral supplements for cattle. Matrix effects were minimized using matrix-matching method and univariate and partial least squares (PLS) treatments. The samples containing predominantly sulphate species were used as standards for calibration. For mineral supplement samples that contain predominantly elemental sulphur species, a sample set or S 8 diluted in Na 2 CO 3 : NaCl (1:1 w/w) were used with standards. No statistically significant difference was observed between method proposed and inductively coupled plasma optical emission spectrometry (ICP OES) reference values at 95% confidence level (Student's t -test, n = 3). The limits of quantification ≤2 g kg−1 S, standard error of calibration ≤3.5 g kg−1 S, standard error of Cross Validation ≤4.7 g kg−1 S values obtained for the models proposed. The relative standard error ≤ 9% were obtained for the proposed method, demonstrating good precision. The method was successfully applied and a good alternative to direct speciation and analysis for determination of S in mineral supplements for cattle. Unlabelled Image • Sulphur speciation in mineral supplement samples • Univariate and multivariate calibration approaches • X-ray fluorescence employing direct solid sample analysis • Proposed method with suitable limits of detection for S [ABSTRACT FROM AUTHOR]

This work utilizes the liquid–liquid extraction technique of aqueous two-phase systems (ATPS) formed by a polymer and electrolyte to develop a novel methodology for the extraction, determination, and speciation analysis of inorganic arsenic. To optimize the methodology, the following parameters were studied: pH of the system, nature of the ATPS-forming electrolyte and the polymer, tie-line length (TLL) of the system, type and concentration of extractants, and the mass ratio of the top and bottom phases. The highest extraction (%E = 98%) was obtained for an ATPS composed of L64 + Na 2 SO 4 + H 2 O, at pH = 6.00, TLL = 33.55% w/w using the ammonium pyrrolidine dithiocarbamate (APDC) extractant in a molar ratio (APDC/As(III)) of 960, and with a mass ratio of 1/4. In these same conditions, As(V) was not extracted satisfactorily (%E = 18%) to ATPS top phase, with a separation factor equal to 530 after three extractions, showing the great potential of the system for the speciation analysis of inorganic arsenic. Moreover, the method was validated employing HG-ICP OES with a coefficient of determination of 0.9957 and limits of detection and quantification equal to 0.20 μg kg−1 and 0.66 μg kg−1, respectively, proving that the method is capable of detecting the low concentrations required by legislation. The relative standard deviation (RSD) values varied between 4.88 and 9.45%, and the RSD in inter-day precision was 11.07%, which are in accordance with the limits of the validation guide used by the National Institute of Metrology, Quality and Technology, COD-CGCRE-008. Furthermore, relative error rates ranged from −7.44 to 9.90% and recovery percentages were between 92.6 and 110% for the accuracy studies. This method was also applied in a spiked tap water sample, presenting a recovery value equal to 87.10%. • Extraction of 98% of the As(III) using aqueous two-phase system • Inorganic arsenic speciation analysis employing APDC as extractant • High separation factor (S As(III)/As(V) = 530) after three successive extractions [ABSTRACT FROM AUTHOR]

Abstract The capability of inductively coupled plasma tandem mass spectrometry (ICP-MS/MS) to achieve total concentration and speciation using direct injection of petroleum products after solvent dilution for severely interfered isotopes was demonstrated here with different applications cases. For the direct determination of heavy elements (Z > 70) in organic matrices, the ICP-MS/MS was less sensitive than the ICP-HRMS. For light elements (Z < 40), the sensitivity was similar or better using ICP-MS/MS and for interfered elements (Si, S, Ca, Fe), the use of the two quadrupoles combined to the octopole reaction/collision cell (ORC) with He, O 2 or H 2 gave similar or better detection limits (LOD) than the ICP-HRMS in medium resolution. Comparable or better sensitivity were obtained replacing the 1.5 mm by the 1 mm injector diameter and especially for lighter elements (Z < 30) using the ICP-MS/MS. LOD in xylene were ranging from 0.004 μg/kg (V) to 0.9 μg/kg (Al) and appeared in the lowest values published in the literature using ICP-MS/MS in hydrocarbons. To demonstrate the performance of the ICP-MS/MS using direct injection of petroleum products after dilution in hydrocarbon solvent, three application cases were presented. Sulfur at very low levels in reformates was successfully monitored in oxygen mode using the oxide ion (32S → 48SO). The background equivalent concentration (BEC) origin was attributed to solvent contamination by sulfur and was confirmed by ultra-violet fluorescence (UVF) method. Using H 2 for Ni (58Ni → 58Ni) and O 2 for V (51V → 67VO) as reactant gas, the direct injection ICP-MS/MS method easily confirmed Ni and V concentrations measured using wavelength dispersive X-rays fluorescence (WDXRF) and allowed the determination of 14 elements in the asphaltene fraction, with concentrations ranging from 0.3 mg/kg (Al and Pb) to 37.4 mg/kg for Fe. For speciation of Ni, V and S, gel permeation chromatography (GPC) hyphenated to ICP-MS/MS is particularly powerful using O 2 (2.5 mL/min) both for vacuum residue and hydrotreated (HDT) vacuum residue. Contrary to GPC-ICP-HRMS where two injections of sample were required (medium resolution for S and V and low resolution for Ni), GPC-ICP-MS/MS easily allowed the acquisition of the 3 elements in one mode during the same run and considerably reduce the analysis cost and time. Both for total and speciation analysis, the direct injection of petroleum products after solvent dilution ICP-MS/MS method is a significant advantage and appealing in high-volume petroleum laboratories. Graphical abstract Unlabelled Image Highlights • The application of direct dilution injection of petroleum products using ICP-MS/MS • Sensitivity for interfered elements is similar or better by ICP-MS/MS than ICP/HRMS • LOD in xylene are ranging from 0.004 µg/kg (V) to 0.9 µg/kg (Al) • Total concentrations by ICP-MS/MS are in agreement with normalized methods • One GPC-ICP-MS/MS analysis is adequate for S, Ni and V speciation in complex matrices [ABSTRACT FROM AUTHOR]

Two simple approaches to speciation analysis of mercury in flue gases have been developed distinguishing between elemental mercury Hg0 and oxidized form of mercury (often HgCl 2) either in off-line or on-line measurement arrangements. Both approaches employ atomic absorption spectrometry (AAS) as a detector. The off-line approach combines a pair of sorbents from which the first one traps oxidized for of mercury (HgCl 2) selectively on a raw alumina sorbent while the second one retains Hg0 quantitatively on a gold-coated alumina filling. Trapped amount of Hg in both sorbents is subsequently determined by AAS employing the advanced mercury analyzer AMA-254. Both sorbents can be regenerated for repeated use. Selectivity and capacity of both sorbents was investigated by means of model gases and compared to other materials. The accuracy and precision of this approach have been proven by analysis of a model flue gas mixture. The on-line approach to speciation analysis is based on direct introduction of flue gases into the AAS spectrometer equipped with an externally heated quartz tube atomizer. The temperature of the atomizer's optical arm or temperature of the gas line upstream the atomizer allow speciation analysis since Hg0 as atomic Hg-vapor can be detected at ambient temperature while HgCl 2 as a molecular species requires heating of the atomizer or gas line to 900 °C. Unlabelled Image • On-line and off-line approaches to Hg speciation analysis in flue gases by AAS. • Allow to distinguish dominating species in flue gases - elemental Hg from HgCl 2. • Atomizer or gas line temperature control speciation analysis in on-line approach. • Off-line approach based on selective Hg species sorption in a pair of sorbents. • Alumina used for HgCl 2 , Au-coated alumina for elemental Hg, AAS detection follows. [ABSTRACT FROM AUTHOR]

Corrosion products, such as 110 mAg, 58Co, 60Co, 51Cr, 54Mn and 125Sb have great contribution to the radioactivity of primary coolant in nuclear power plant (NPP). It is considered that some of these nuclides are probably in colloidal form, since they cannot be effectively removed by the conventional ion exchange process in NPP. In this paper, the chemical speciation and behavior of these nuclides in the primary coolant was investigated by simulation calculation and validation experiments. In the reductive circumstance of primary coolant during power operation and re-operation preparatory stage in a normal operation process of reactor, nuclides such as 51Cr, 54Mn, 58Co and 60Co are mainly present as ions of Mn2+ and Cr2+, as well as Co2+ with the possibility of forming Co(OH) n 2-n colloid in a high activity. Meanwhile, 110 mAg can be reduced to Ag0 with a form of nano-silver cluster or nano-silver metal particles in a size of 10–100 nm, and 125Sb mainly exists in the form of soluble anion SbO 2 - or hydrolyzed granular Sb 2 O 3. During shutdown oxidation process, 110 mAg and 125Sb can be oxidized by the added hydrogen peroxide into Ag+ ions and anion SbO 3 - leading to an increased solubility in coolant. Meanwhile 51Cr and 54Mn can be oxidized into Cr(III) and Mn (IV), which can form the co-existing state of many hydroxyl complexes, such as Cr(OH)n3-n, Mn(OH) n 4-n or MnO 2. It indicated that metallic silver particles Ag0 and some metal hydrated hydroxide, such as Co(OH)n2-n, Cr(OH) n 3-n and Mn(OH) n 4-n may be responsible for the formation of colloids in the primary coolant. • Ag exists mainly as Ag0 particles in size of 10–100 nm in primary coolant. • 110 mAg emission increase since Ag0 is oxidized into Ag+ by H 2 O 2 in shutdown process. • Colloids of Co(OH)n2-n, Cr(OH) n 3-n and Mn(OH) n 4-n may be formed in core coolant. • Sb mainly exists in SbO 2 - or hydrolyzed granular Sb 2 O 3 at power operation stage. • Anion SbO 3 - is formed in shutdown process due to the oxidation by H 2 O 2 in coolant. [ABSTRACT FROM AUTHOR]

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