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1.
Food Chem ; 345: 128781, 2021 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-33601653

RESUMO

A new iron-magnetic nanomaterial functionalized with organophosphorus compound was used as solid-phase for arsenic speciation analysis in seafood samples by ICP-MS. The procedure was optimized using chemometric tools and the variables pH = 4.0, 15 min extraction time, and 20 mg of mass of material were obtained as the optimum point. The inorganic arsenic (iAs) extracted using nanoparticles presented concentrations between 20 and 100 µg kg-1 in the evaluated samples. The method was validated for accuracy using CRMs DOLT-5 and DORM-4. It was possible to reuse the same magnetic nanomaterial for 6 successive cycles, and we obtained a detection limit of 16.4 ng kg-1. The proposed method is suitable for the use of inorganic speciation of As, presenting good accuracy, precision, relatively low cost, and acquittance to green chemistry principles.


Assuntos
Arsenicais/análise , Nanopartículas de Magnetita/química , Espectrometria de Massas , Penaeidae/química , Animais , Arsenicais/isolamento & purificação , Cromatografia Líquida de Alta Pressão , Óxido Ferroso-Férrico/química , Limite de Detecção , Penaeidae/metabolismo , Alimentos Marinhos/análise
2.
Food Chem ; 347: 129054, 2021 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-33484954

RESUMO

The novel molecularly imprinted microspheres for four phenylarsonic compounds have been firstly prepared with the reversible addition-fragmentation chain transfer polymerization in a suspension system. The resulting polymeric microspheres were characterized by infrared spectrum, scanning electron microscope and differential scanning calorimetry. With serial adsorption experiments, the polymeric microspheres showed highly specific molecular recognition, fast mass transfer rate and robust adsorption of the substrates. Then, the imprinted polymer was used as the solid-phase extraction adsorbent to extract the phenylarsonic compounds from the feeds, edible chicken and pork. The cartridge was washed with 2 mL ethyl acetate and eluted with 3 mL of methanol- acetic acid (90:10, v/v). The recoveries of the molecularly imprinted solid-phase extraction (MISPE) column ranged from 83.4% to 95.1%. This work provided a versatile approach for the specific extraction of the organoarsenic compounds from complicated matrices and exhibited a bright future for the application of MISPE column.


Assuntos
Ração Animal/análise , Arsenicais/análise , Carne/análise , Impressão Molecular , Polímeros/química , Extração em Fase Sólida/métodos , Adsorção , Animais , Ácido Arsanílico/análogos & derivados , Ácido Arsanílico/análise , Ácido Arsanílico/isolamento & purificação , Arsenicais/isolamento & purificação , Galinhas , Cromatografia Líquida de Alta Pressão , Músculos/química , Roxarsona/análise , Roxarsona/isolamento & purificação , Suínos
3.
Electrophoresis ; 42(4): 465-472, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33049065

RESUMO

Ti (IV)-modified vinyl phosphate magnetic nanoparticles (Fe3 O4 @SiO2 @KH570-PO4 -Ti (IV)) was prepared for simultaneous extraction of multiple arsenic species, followed by high performance liquid chromatography (HPLC)- inductively coupled plasma mass spectrometry (ICP-MS) analysis. Inorganic arsenic (iAs), dimethyl arsenic acid (DMA), monomethyl arsenic acid (MMA), p-amino phenyl arsenic acid (p-ASA), 4-hdroxyphenylarsenic acid (4-OH), phenyl arsenic acid (PAA), and 3-nitro-4-hydroxyphenylarsenic acid (ROX) were investigated as interest analytes. It was found that they were quantitatively adsorbed on Fe3 O4 @SiO2 @KH570-PO4 -Ti (IV) at pH 5, and desorbed completely with 0.1 mol/L sodium hydroxide solution. Enrichment factor of 100-fold was obtained by consuming 100 mL sample solution. Under the optimal conditions, the method combining MSPE with HPLC-ICP-MS presented a linear range of 1-5000 ng/L for seven arsenic species. The limits of detection were 0.39, 0.60, 0.23, 1.85, 0.54, 0.48, and 0.84 ng/L for DMA, MMA, p-ASA, iAs, 4-OH, PAA, ROX, with the relative standard deviations (c = 10 ng/L, n = 7) of 3.6, 3.9, 5.5, 12.4, 6.1, 5.8, 5.0, respectively. The accuracy of the method was validated by analyzing BCR 627 Tuna fish. The application potential of the method was further evaluated by chicken muscle and liver samples. No target arsenic species were detected in these samples, and good recoveries (80.6-123%) were obtained for the spiked samples at low, medium, and high concentration levels.


Assuntos
Arsênio , Arsenicais , Cromatografia Líquida de Alta Pressão/métodos , Nanopartículas de Magnetita/química , Espectrometria de Massas/métodos , Animais , Arsênio/análise , Arsênio/química , Arsênio/isolamento & purificação , Arsenicais/análise , Arsenicais/química , Arsenicais/isolamento & purificação , Galinhas , Limite de Detecção , Modelos Lineares , Fígado/química , Carne/análise , Músculos/química , Compostos Organofosforados/química , Reprodutibilidade dos Testes , Titânio/química , Atum , Compostos de Vinila/química
4.
Food Chem ; 338: 128028, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33091983

RESUMO

Direct determination of arsenic species in real samples is challenging due to their trace concentration and spectral interferences by coexisting ions. Herein, we proposed an ultrasound-assisted dispersive solid phase microextraction (DSPME) procedure for the analyses of the trace inorganic arsenic. The hydrothermally synthesized cadmium sulfide nanoparticles (CdS NPs) completely adsorbed both arsenic species within 20 s at the initial arsenic concentration of 100 µg L-1. The detection limit (3 S/m) of the proposed method was found to be 0.5 ± 0.2 and 0.8 ± 0.2 ng L-1 for As(III) and As(V), respectively. The accuracy of the method against the systematic and constant errors was confirmed by the analysis of the Standard Reference Material (SRM) (>95% recovery with <5% RSD). The Student's t-test values were found to be less than the critical Student's t value at a 95% confidence level. The method was successfully employed for the determination of arsenic in food samples.


Assuntos
Arsenicais/análise , Análise de Alimentos , Nanopartículas/química , Espectrofotometria/métodos , Adsorção , Arsenicais/isolamento & purificação , Compostos de Cádmio/química , Humanos , Concentração de Íons de Hidrogênio , Microextração em Fase Sólida , Sonicação , Sulfetos/química
5.
Int J Biol Macromol ; 164: 13-26, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32679323

RESUMO

A goethite/graphene oxide/chitosan (α-FeO(OH)/GO/CS) nanocomposite adsorbent was prepared and firstly used to remove As(III) from aqueous solution. The composite was characterized by FTIR, XPS, XRD, and EDS techniques. Batch experiments were conducted to investigate the effects of several factors (initial concentration, pH, m/v, contact time, co-existing ions, and temperature) on As(III) adsorption and to evaluate adsorption kinetic, equilibrium isotherm, and thermodynamics. Results showed that As(III) adsorption increased with the increasing initial concentration, contact time, and temperature, but decreased with the increasing m/v and co-existing ions concentrations of SO42-, PO43- and Fe3+. As(III) adsorption remained high at a wide pH range of 3-10. The adsorption was well fitted to a pseudo-second-order kinetic model and was endothermic and spontaneous. The best fit of As(III) adsorption with the Freundlich and Sips models indicated that it was monolayer adsorption, and the maximum adsorption capacity was 289.42 mg/g. As(III) removal was related to -NHCO-, CO, OH, and FeO groups, but the complexation between As(III) ions and hydroxyl iron oxide was the major contributor. After the fifth desorption, the removal efficiency was still as high as 79.6%, indicating excellent reusability. Thus, this composite had great potential for removing As(III) from aqueous solutions.


Assuntos
Arsenicais/isolamento & purificação , Quitosana/química , Grafite/química , Compostos de Ferro/química , Minerais/química , Nanocompostos/química , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Adsorção , Arsenicais/química , Concentração de Íons de Hidrogênio , Íons , Microscopia Eletrônica de Varredura , Espectroscopia Fotoeletrônica , Espectrometria por Raios X , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura , Termodinâmica , Poluentes Químicos da Água/química , Difração de Raios X
6.
Chemosphere ; 260: 127566, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32663674

RESUMO

Ball milling was used to fabricate a nanocomposite of 20% hickory biochar (600 °C) and 80% expanded vermiculite (20%-BC/VE). This novel composite adsorbent had much higher removal of As(V) from aqueous solutions than ball-milled biochar and expanded vermiculite. Characterization of these adsorbents showed that the enhanced As(V) adsorption was ascribed to much larger surface area and pore volume (2-6 times), notable changes in crystallinity, activation of cations, and increased functional groups in the nanocomposite compared with the ball-milled products of their pristine counterparts. The As(V) adsorption process by the 20%-BC/VE fitted well with the pseudo-second-order kinetic model (R2= 0.990) and Langmuir isotherm model (R2= 0.989) with a maximum adsorption capacity of 20.1 mg g-1. The 20%-BC/VE best performed at pH about 6. The adsorption efficiency was not sensitive to the competition of NO3-, Cl-, SO42-, as well as the coexistence of humic acid. However, the adsorption capacity for As(V) was significantly reduced by coexisting with PO43-. The 20%-BC/VE composite can potentially serve as a superior low-cost adsorbent for As(V) removal in real-world applications.


Assuntos
Silicatos de Alumínio/química , Arsenicais/isolamento & purificação , Carvão Vegetal/química , Nanocompostos/química , Poluentes Químicos da Água/isolamento & purificação , Adsorção , Cinética , Poluentes Químicos da Água/análise , Purificação da Água/métodos
7.
J Agric Food Chem ; 68(7): 1910-1934, 2020 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-31999115

RESUMO

Setting regulatory limits for arsenic in food is complicated, owing to the enormous diversity of arsenic metabolism in humans, lack of knowledge about the toxicity of these chemicals, and lack of accurate arsenic speciation data on foodstuffs. Identification and quantification of the toxic arsenic compounds are imperative to understanding the risk associated with exposure to arsenic from dietary intake, which, in turn, underscores the need for speciation analysis of the food. Arsenic speciation in seafood is challenging, owing to its existence in myriads of chemical forms and oxidation states. Interconversions occurring between chemical forms, matrix complexity, lack of standards and certified reference materials, and lack of widely accepted measurement protocols present additional challenges. This review covers the current analytical techniques for diverse arsenic species. The requirement for high-quality arsenic speciation data that is essential for establishing legislation and setting regulatory limits for arsenic in food is explored.


Assuntos
Arsenicais/química , Técnicas de Química Analítica/métodos , Análise de Alimentos/métodos , Contaminação de Alimentos/análise , Alimentos Marinhos/análise , Animais , Arsenicais/isolamento & purificação
8.
Anal Chem ; 91(13): 8280-8288, 2019 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-31199622

RESUMO

Surface-enhanced Raman spectroscopy (SERS), as a nondestructive and fast detection technique, is a promising alternative approach for arsenic detection, particularly for in situ applications. SERS-based speciation analysis according to the fingerprint SERS signals of different arsenicals has the potential to provide a superior technique in species preservation over the conventional chromatographic separation methods, albeit with some difficulties due to the similarity in SERS patterns. In this study, we explored a novel SERS method for arsenic speciation by using the separation potential of the coffee ring effect on negatively charged silver nanofilms (AgNFs). Four arsenic species, including arsenite (AsIII), arsenate (AsV), monomethylarsonic acid (MMAV), and dimethylarsinic acid (DMAV), were measured for fingerprint SERS signals in solution and on the films. Significant enhancement of SERS signals on the dried coffee ring stains by the AgNFs were observed except for AsIII, and more importantly, arsenicals migrated varying distances during coffee ring development, promoting better speciation. Sodium dodecyl sulfate was then introduced into the droplet to reduce the droplet surface tension, facilitating the migration of solution into the peripheral region. Under the combined interactions of arsenicals with the AgNFs, solvent, and surfactant, enhanced separation between arsenicals was observed as a result of the formation of two concentric rings. Combining the SERS fingerprint signals and physical separation of arsenicals on the surface, arsenic speciation was achieved using the AgNFs substrate-based SERS technology, demonstrating the potential of the coffee ring effect for rapid separation and analysis of small molecules by SERS.


Assuntos
Arsênio/análise , Nanopartículas Metálicas/química , Arsênio/química , Arsenicais/análise , Arsenicais/isolamento & purificação , Prata , Análise Espectral Raman/métodos
9.
Phytochemistry ; 164: 243-251, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31128818

RESUMO

Lipid-like compounds containing a dimethylarsinoyl group, i.e. Me2As(O)-, have been identified by liquid chromatography/inductively coupled plasma mass spectrometry (LC/ICP-MS) and non-aqueous reversed-phase high-performance liquid chromatography (positive and/or negative high-resolution tandem electrospray ionization mass spectrometry (NARP-HPLC/HR-ESI+(-)-MS/MS) from three strains of green algae of the genus Coccomyxa (Trebouxiophyceae, Chlorophyta). The algae were cultivated in a medium containing 10 g arsenic/L, i.e. 133.5 mmol/L of Na2HAsO4.7H2O. After extraction by methyl-tert-butyl ether (MTBE), total lipids were analyzed by ICP-MS or ESI-MS without any further separation or fractionation. A total of 39 molecular species of arsenic triacylglycerols (AsTAG), 15 arsenic phosphatidylcholines (AsPC), 8 arsenic phosphatidylethanolamines (AsPE), 6 arsenic phosphatidylinositols (AsPI), 2 arsenic phosphatidylglycerols (AsPG) and 5 unknown lipids (probably ceramides) were identified. The structures of all molecular species were confirmed by tandem MS. Dry matter of the individual strains contained different amounts of total arsenolipids, i.e. C. elongata CCALA 427 (0.32 mg/g), C. onubensis (1.48 mg/g), C. elongata S3 (2.13 mg/g). On the other hand, there were only slight differences between strains in the relative abundances of individual molecular species. Possible biosynthesis of long-chain lipids with the end group Me2As(O) has also been suggested.


Assuntos
Arsenicais/isolamento & purificação , Chlorella/química , Lipídeos/isolamento & purificação , Arsenicais/química , Arsenicais/metabolismo , Chlorella/metabolismo , Lipídeos/química , Estrutura Molecular
10.
Artigo em Inglês | MEDLINE | ID: mdl-31046566

RESUMO

The multi-walled carbon nanotubes-branched polyethyleneimine (MWCNTs-BPEI) adsorbent composite material was employed to separate and pre-concentrate As(V) in water samples. The characterization of MWCNTs-BPEI by X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy and Raman spectroscopy showed successful modification of the composite. The MWCNTs-BPEI composite exhibited selective retention of As(V) in the presence of As(III) in water samples of pH 7 using 40 mg of composite as adsorbent. The pre-concentrated As(V) was quantified using inductively coupled plasma-mass spectrometry (ICP-MS). A limit of detection (LOD) of 0.0537 µg L-1 and limit of quantification (LOQ) of 0.179 µg L-1 were achieved along with pre-concentration factor of 23.3. A percentage recovery of 81.0% confirm the accuracy of the method. The As(V) concentrations in water were in the range of 0.0612-3.65 µg L-1. The As(V) concentrations determined using solid-phase extraction (SPE) procedure were in good agreement with the concentrations obtained using high performance liquid chromatography hyphenated to inductively coupled mass-mass spectrometry (HPLC hyphenated to ICP-MS).


Assuntos
Arsenicais/isolamento & purificação , Nanocompostos/química , Extração em Fase Sólida/métodos , Poluentes Químicos da Água/isolamento & purificação , Cromatografia Líquida de Alta Pressão , Limite de Detecção , Espectrometria de Massas , Nanotubos de Carbono/química
11.
Commun Biol ; 2: 131, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30993215

RESUMO

The emergence and spread of antimicrobial resistance highlights the urgent need for new antibiotics. Organoarsenicals have been used as antimicrobials since Paul Ehrlich's salvarsan. Recently a soil bacterium was shown to produce the organoarsenical arsinothricin. We demonstrate that arsinothricin, a non-proteinogenic analog of glutamate that inhibits glutamine synthetase, is an effective broad-spectrum antibiotic against both Gram-positive and Gram-negative bacteria, suggesting that bacteria have evolved the ability to utilize the pervasive environmental toxic metalloid arsenic to produce a potent antimicrobial. With every new antibiotic, resistance inevitably arises. The arsN1 gene, widely distributed in bacterial arsenic resistance (ars) operons, selectively confers resistance to arsinothricin by acetylation of the α-amino group. Crystal structures of ArsN1 N-acetyltransferase, with or without arsinothricin, shed light on the mechanism of its substrate selectivity. These findings have the potential for development of a new class of organoarsenical antimicrobials and ArsN1 inhibitors.


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Arsenicais/química , Arsenicais/farmacologia , Burkholderia gladioli/metabolismo , Ácido Glutâmico/análogos & derivados , Acetilação , Antibacterianos/isolamento & purificação , Arsenicais/isolamento & purificação , Burkholderia gladioli/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Escherichia coli/metabolismo , Genes Bacterianos/genética , Glutamato-Amônia Ligase/análise , Humanos , Testes de Sensibilidade Microbiana , Mycobacterium bovis/efeitos dos fármacos , Óperon , Células THP-1
12.
Nano Lett ; 19(4): 2674-2681, 2019 04 10.
Artigo em Inglês | MEDLINE | ID: mdl-30908918

RESUMO

We report on experimental determination of the strain and bandgap of InAsP in epitaxially grown InAsP-InP core-shell nanowires. The core-shell nanowires are grown via metal-organic vapor phase epitaxy. The as-grown nanowires are characterized by transmission electron microscopy, X-ray diffraction, micro-photoluminescence (µPL) spectroscopy, and micro-Raman (µ-Raman) spectroscopy measurements. We observe that the core-shell nanowires are of wurtzite (WZ) crystal phase and are coherently strained with the core and the shell having the same number of atomic planes in each nanowire. We determine the predominantly uniaxial strains formed in the core-shell nanowires along the nanowire growth axis and demonstrate that the strains can be described using an analytical expression. The bandgap energies in the strained WZ InAsP core materials are extracted from the µPL measurements of individual core-shell nanowires. The coherently strained core-shell nanowires demonstrated in this work offer the potentials for use in constructing novel optoelectronic devices and for development of piezoelectric photovoltaic devices.


Assuntos
Arsenicais/isolamento & purificação , Medições Luminescentes/métodos , Nanofios/química , Arsenicais/química , Estruturas Metalorgânicas/química , Tamanho da Partícula , Análise Espectral Raman , Difração de Raios X
13.
Homeopathy ; 108(1): 12-23, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30290377

RESUMO

INTRODUCTION: According to the "silica hypothesis" formulated to explain homeopathy, the information of starting materials would be transferred to cells by silica nanoparticles detached from the glassware walls by serial dilution and agitation through epitaxy. We compared the biological activity, electrical current and silicon microparticle content (by means of scanning electron microscopy/energy-dispersive X-ray spectroscopy) of high dilutions (HDs) of arsenic prepared in plastic and glass vials to investigate the role of silica in their biological effects in vitro. MATERIALS AND METHODS: Co-cultures of macrophages and yeast (Saccharomyces cerevisiae) were treated with different HDs of arsenic prepared in plastic and glass vials. Macrophage morphology, phagocytosis index, nitric oxide (NO), and cytokine production were evaluated. RESULTS: Measurable amounts of silicon microparticles were detected only in the HDs prepared in glass vials, but ultra-centrifugation eliminated them. Specific and non-specific results were observed. Non-specific pro-inflammatory effects were seen in all dilutions prepared in plastic vials, including elevation of pro-inflammatory cytokines, NO and macrophage phagocytic index. Only the 200th centesimal dilution of arsenic produced specific decrease in interleukin-6 production in macrophages, and it was independent of the vial type or the presence of microparticles of silica in the medicine samples. The nature of the vials had an impact on the electric flow in the respective fluids. CONCLUSION: The non-specific, pro-inflammatory effects might be attributed to organic residuals detached from the vials' plastic walls during manipulation. Instead, specific silica-independent effects of the homeopathic medicine can be attributed to the decrease of interleukin-6 after treatment with the 200th centesimal dilution of arsenic.


Assuntos
Arsenicais/isolamento & purificação , Condutividade Elétrica , Silício/isolamento & purificação , Citocinas/isolamento & purificação , Homeopatia/métodos , Humanos , Microscopia Eletrônica de Varredura/métodos
14.
J Chromatogr Sci ; 56(9): 853-857, 2018 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-30084966

RESUMO

Arsenic exists in the form of various chemical species differing in their physicochemical behavior, toxicity, bioavailability and biotransformation. The determination of arsenic species is an important issue for environmental, clinical and food chemistry. However, differentiation of these species is a quite complex analytical task. Numerous speciation procedures have been studied that include electrochemical, chromatographic, spectrometric and hyphenated techniques. Ion exchange chromatography is one of the techniques used to speciate inorganic arsenic i.e., arsenic (III) and arsenic (V). Both of these arsenic species are stable and exist as anions, arsenic (III) as arsenite (AsO33-) and arsenic (V) as arsenate (AsO43-). The proposed method can be used to perform the speciation of arsenic (III) and arsenic (V). It is a two-step process, first arsenic (V) is determined, followed by total arsenic determination by treating the sample with potassium permanganate solution to oxidize the arsenic (III) present in the sample to arsenic (V) and determining it as arsenic (V). Addition of potassium permanganate solution to the ground water samples for oxidizing the arsenic (III) to arsenic (V) is the newly adopted sample preparation technique and further determining it by ion exchange chromatography with conductivity detection. This method can be used for arsenic speciation in water samples from rivers and under the ground. Analytical validation and performance of the method is also discussed.


Assuntos
Arsenicais/análise , Cromatografia por Troca Iônica/métodos , Água Subterrânea/química , Poluentes Químicos da Água/análise , Arsenicais/química , Arsenicais/isolamento & purificação , Desenho de Equipamento , Limite de Detecção , Modelos Lineares , Reprodutibilidade dos Testes , Poluentes Químicos da Água/química , Poluentes Químicos da Água/isolamento & purificação
15.
Talanta ; 188: 107-110, 2018 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-30029352

RESUMO

The arsenic speciation was determined in macrofungi of the Ramaria genus with HPLC coupled to inductively coupled plasma mass spectrometry. Besides arsenic species that are already known for macrofungi, like arsenobetaine or arsenocholine, two compounds that were only known from marine samples so far (trimethylarsoniopropanate and dimethylarsinoylacetate) were found for the first time in a terrestrial sample. An unknown arsenical was isolated and identified as homoarsenocholine. This could be a key intermediate for further elucidation of the biotransformation mechanisms of arsenic.


Assuntos
Arsenicais/isolamento & purificação , Acetatos/química , Acetatos/isolamento & purificação , Arsenicais/química , Basidiomycota/química
16.
Anal Bioanal Chem ; 410(9): 2283-2290, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29430602

RESUMO

Arsenic and its species were investigated for the first time in nine collections of Elaphomyces spp. ("deer truffles") from the Czech Republic with inductively coupled plasma mass spectrometry (ICPMS) and high-performance liquid chromatography coupled to ICPMS. The total arsenic concentrations ranged from 12 to 42 mg kg-1 dry mass in samples of E. asperulus and from 120 to 660 mg kg-1 dry mass in E. granulatus and E. muricatus. These concentrations are remarkably high for terrestrial organisms and demonstrate the arsenic-accumulating ability of these fungi. The dominating arsenic species in all samples was methylarsonic acid which accounted for more than 30% of the extractable arsenic. Arsenobetaine, dimethylarsinic acid, and inorganic arsenic were present as well, but only at trace concentrations. Surprisingly, we found high amounts of trimethylarsine oxide in all samples (0.32-28% of the extractable arsenic). Even more remarkable was that all but two samples contained significant amounts of the highly toxic trivalent arsenic compound methylarsonous acid (0.08-0.73% of the extractable arsenic). This is the first report of the occurrence of trimethylarsine oxide and methylarsonous acid at significant concentrations in a terrestrial organism. Our findings point out that there is still a lot to be understood about the biotransformation pathways of arsenic in the terrestrial environment. Graphical abstract Trimethylarsine oxide and methylarsonous acid in "deer truffles".


Assuntos
Arsenicais/análise , Eurotiales/química , Arsenicais/isolamento & purificação , Cromatografia Líquida de Alta Pressão/métodos , Monitoramento Ambiental/métodos , Espectrometria de Massas/métodos
17.
J Ethnopharmacol ; 210: 340-350, 2018 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-28864167

RESUMO

ETHNOPHARMOCOLOGICAL RELEVANCE: Herbo-metallic preparations have a long history in the treatment of diseases, and are still used today for refractory diseases, as adjuncts to standard therapy, or for economic reasons in developing countries. AIM OF THE REVIEW: This review uses cinnabar (HgS) and realgar (As4S4) as mineral examples to discuss their occurrence, therapeutic use, pharmacology, toxicity in traditional medicine mixtures, and research perspectives. MATERIALS AND METHODS: A literature search on cinnabar and realgar from PubMed, Chinese pharmacopeia, Google and other sources was carried out. Traditional medicines containing both cinnabar and realgar (An-Gong-Niu-Huang Wan, Hua-Feng-Dan); mainly cinnabar (Zhu-Sha-An-Shen Wan; Zuotai and Dangzuo), and mainly realgar (Huang-Dai Pian; Liu-Shen Wan; Niu-Huang-Jie-Du) are discussed. RESULTS: Both cinnabar and realgar used in traditional medicines are subjected to special preparation procedures to remove impurities. Metals in these traditional medicines are in the sulfide forms which are different from environmental mercurials (HgCl2, MeHg) or arsenicals (NaAsO2, NaH2AsO4). Cinnabar and/or realgar are seldom used alone, but rather as mixtures with herbs and/or animal products in traditional medicines. Advanced technologies are now used to characterize these preparations. The bioaccessibility, absorption, distribution, metabolism and elimination of these herbo-metallic preparations are different from environmental metals. The rationale of including metals in traditional remedies and their interactions with drugs need to be justified. At higher therapeutic doses, balance of the benefits and risks is critical. Surveillance of patients using these herbo-metallic preparations is desired. CONCLUSION: Chemical forms of mercury and arsenic are a major determinant of their disposition, efficacy and toxicity, and the use of total Hg and As alone for risk assessment of metals in traditional medicines is insufficient.


Assuntos
Arsenicais/farmacologia , Medicina Tradicional/métodos , Compostos de Mercúrio/farmacologia , Sulfetos/farmacologia , Animais , Arsenicais/administração & dosagem , Arsenicais/isolamento & purificação , Relação Dose-Resposta a Droga , Interações Medicamentosas , Etnofarmacologia , Humanos , Compostos de Mercúrio/administração & dosagem , Compostos de Mercúrio/isolamento & purificação , Sulfetos/administração & dosagem , Sulfetos/isolamento & purificação
18.
J Hazard Mater ; 321: 764-772, 2017 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-27720469

RESUMO

Acid mine drainages (AMD) are major sources of pollution to the environment. Passive bio-remediation technologies involving sulfate-reducing bacteria (SRB) are promising for treating arsenic contaminated waters. However, mechanisms of biogenic As-sulfide formation need to be better understood to decontaminate AMDs in acidic conditions. Here, we show that a high-As AMD effluent can be decontaminated by an indigenous SRB consortium. AMD water from the Carnoulès mine (Gard, France) was incubated with the consortium under anoxic conditions and As, Zn and Fe concentrations, pH and microbial activity were monitored during 94days. Precipitated solids were analyzed using electron microscopy (SEM/TEM-EDXS), and Extended X-Ray Absorption Fine Structure (EXAFS) spectroscopy at the As K-edge. Total removal of arsenic and zinc from solution (1.06 and 0.23mmol/L, respectively) was observed in two of the triplicates. While Zn precipitated as ZnS nanoparticles, As precipitated as amorphous orpiment (am-AsIII2S3) (33-73%), and realgar (AsIIS) (0-34%), the latter phase exhibiting a particular nanowire morphology. A minor fraction of As is also found as thiol-bound AsIII (14-23%). We propose that the formation of the AsIIS nanowires results from AsIII2S3 reduction by biogenic H2S, enhancing the efficiency of As removal. The present description of As immobilization may help to set the basis for bioremediation strategies using SRB.


Assuntos
Arsênio/isolamento & purificação , Resíduos Industriais/análise , Mineração , Bactérias Redutoras de Enxofre/metabolismo , Poluentes Químicos da Água/metabolismo , Zinco/isolamento & purificação , Arsenicais/química , Arsenicais/isolamento & purificação , Biodegradação Ambiental , Descontaminação , Desulfovibrio , Concentração de Íons de Hidrogênio , Nanofios , Sulfetos/química , Sulfetos/isolamento & purificação , Poluentes Químicos da Água/química , Difração de Raios X , Compostos de Zinco/química , Compostos de Zinco/isolamento & purificação
19.
Chemosphere ; 168: 529-538, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27852449

RESUMO

The iron-reducing bacterium Acidiphilium cryputum JF-5 and a sulfate reducing bacterium (SRB) collected and purified from the mine drainage of a copper mine in the northwest of Sichuan Province, China, were used to biologically synthesize nano-sized FeS-coated limestone to remove As(V) from solution. The adsorption efficiency of As(V) is improved from 6.64 µg/g with limestone alone to 187 µg/g with the FeS coated limestone in both batch and column experiments. The hydraulic conductivity of the columns are also improved by the presence of the nano-sized FeS coatings, but the solution neutralization performance of the limestone can be reduced by passivation by gypsum and Fe(III) precipitates. Calculations for FeS-coated limestone dissolution experiments show that the process can be described as nCa.sol = At1/2 - nCa,gyp. The results suggest that FeS-coated limestone may be an effective medium for remediating As(V)-bearing solutions such as acid mine drainage in systems such as Permeable Reactive Barriers.


Assuntos
Arsenicais/isolamento & purificação , Carbonato de Cálcio/química , Compostos Ferrosos/química , Mineração , Nanopartículas/química , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Acidiphilium/crescimento & desenvolvimento , Adsorção , Biodegradação Ambiental , China , Desulfovibrio vulgaris/crescimento & desenvolvimento , Água Subterrânea/química , Água Subterrânea/microbiologia , Oxirredução
20.
J Chromatogr A ; 1462: 44-54, 2016 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-27495368

RESUMO

The application of different ionic liquids (ILs) as modifiers for chromatographic separation and determination of arsenite [As(III)], arsenate [As(V)], dimethylarsonic acid (DMA) and monomethylarsonic acid (MMA) species in wine samples, by reversed-phase high performance liquid chromatography coupled to hydride generation atomic fluorescence spectrometry detection (RP-HPLC-HG-AFS) was studied in this work. Several factors influencing the chromatographic separation of the As species, such as pH of the mobile phase, buffer solution concentration, buffer type, IL concentration and length of alkyl groups in ILs were evaluated. The complete separation of As species was achieved using a C18 column in isocratic mode with a mobile phase composed of 0.5% (v/v) 1-octyl-3-methylimidazolium chloride ([C8mim]Cl) and 5% (v/v) methanol at pH 8.5. A multivariate methodology was used to optimize the variables involved in AFS detection of As species after they were separated by HPLC. The ILs showed remarkable performance for the separation of As species, which was obtained within 18min with a resolution higher than 0.83. The limits of detection for As(III), As(V), MMA and DMA were 0.81, 0.89, 0.62 and 1.00µg As L(-1). The proposed method was applied for As speciation analysis in white and red wine samples originated from different grape varieties.


Assuntos
Arsênio/análise , Arsênio/isolamento & purificação , Líquidos Iônicos/química , Espectrometria de Fluorescência/métodos , Espectrofotometria Atômica/métodos , Vinho/análise , Arsênio/química , Arsenicais/análise , Arsenicais/isolamento & purificação , Arsenitos/análise , Arsenitos/isolamento & purificação , Soluções Tampão , Cromatografia Líquida de Alta Pressão , Concentração de Íons de Hidrogênio , Limite de Detecção , Vitis/química , Vitis/classificação
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