Arsenic detection
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A slurry sampling procedure for arsenic speciation analysis in baby food by arsane generation, cryogenic trapping and detection with atomic absorption spectrometry is presented. Several procedures were tested for slurry preparation, including different reagents (HNO3, HCl and tetramethylammonium hydroxide - TMAH) and their concentrations, water bath heating and ultrasound-assisted agitation. The best results for inorganic arsenic (iAs) and dimethylarsinate (DMA) were reached when using 3molL-1 HCl under heating and ultrasound-assisted agitation. The developed method was applied for the analysis of five porridge powder and six baby meal samples. The trueness of the method was checked with a certified reference material (CRM) of total arsenic (tAs), iAs and DMA in rice (ERM-BC211). Arsenic recoveries (mass balance) for all samples and CRM were performed by the determination of the tAs by inductively coupled plasma mass spectrometry (ICP-MS) after microwave-assisted digestion and its comparison against the sum of the results from the speciation analysis. The relative limits of detection were 0.44, 0.24 and 0.16µgkg-1 for iAs, methylarsonate and DMA, respectively. The concentrations of the most toxic arsenic species (iAs) in the analyzed baby food samples ranged between 4.2 and 99µgkg-1 which were below the limits of 300, 200 and 100µgkg-1 set by the Brazilian, Chinese and European legislation, respectively.
- MeSH
- analýza potravin přístrojové vybavení metody MeSH
- arsen analýza MeSH
- arsenikové přípravky analýza MeSH
- design vybavení MeSH
- kojenec MeSH
- kontaminace potravin analýza MeSH
- kyselina kakodylová analýza MeSH
- lidé MeSH
- mikrovlny MeSH
- novorozenec MeSH
- potrava pro kojence analýza MeSH
- rýže (rod) chemie MeSH
- spektrofotometrie atomová přístrojové vybavení metody MeSH
- vibrace ultrazvukové přístrojové vybavení metody MeSH
- Check Tag
- kojenec MeSH
- lidé MeSH
- novorozenec MeSH
- Publikační typ
- časopisecké články MeSH
Extensive information is available on total arsenic in particulate matter (PM), but little is known about the relative contribution of each individual species. Recent studies often focus on inorganic arsenic as arsenite and arsenate, neglecting the organoarsenicals, i.e., methylarsine, dimethylarsine, and trimethylarsine or the corresponding oxidized forms methylarsonate, dimethylarsinate, and trimethylarsine oxide, although they were already first detected in PM in the mid-1970s. This work presents results from more than 300 daily PM10 and further size-resolved atmospheric PM samples in the size range from 15 nm to 10 μm collected in an urban environment in Austria during the course of a year. An ion-exchange-HPLC (with anion and cation exchange columns) and an ICPMS/MS system were used to study the seasonal variations of total arsenic and all species known to exist in PM. Inorganic arsenic was present in significant amounts in all samples with highest concentrations during winter, but also all organoarsenicals were detected throughout the year. We show that their contribution cannot be ignored, as particles smaller than <1 μm can contain up to 35% of the water+H2O2 extractable arsenic as methylated species, but only dimethylarsinate showed a clear seasonal trend throughout the year.
- MeSH
- arsen analýza MeSH
- peroxid vodíku MeSH
- pevné částice MeSH
- roční období MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Rakousko MeSH
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.
A proof of concept of a novel pervaporation sequential injection (PSI) analysis method for automatic non-chromatographic speciation analysis of inorganic arsenic in complex aqueous samples is presented. The method is based on hydride generation of arsine followed by its on-line pervaporation-based membrane separation and CCD spectrophotometric detection. The concentrations of arsenite (As(III)) and arsenate (As(V)) are determined sequentially in a single sample zone. The leading section of the sample zone merges with a citric acid/citrate buffer solution (pH 4.5) for the selective reduction of As(III) to arsine while the trailing section of the sample zone merges with hydrochloric acid solution to allow the reduction of both As(III) and As(V) to arsine at pH lower than 1. Virtually identical analytical sensitivity is obtained for both As(III) and As(V) at this high acidity. The flow analyzer also accommodates in-line pH detector for monitoring of the acidity throughout the sample zone prior to hydride generation. Under optimal conditions the proposed PSI method is characterized by a limit of detection, linear calibration range and repeatability for As(III) of 22 μg L(-1) (3sblank level criterion), 50-1000 μg L(-1) and 3.0% at the 500 μg L(-1) level and for As(V) of 51 μg L(-1), 100-2000 μg L(-1) and 2.6% at the 500 μg L(-1) level, respectively. The method was validated with mixed As(III)/As(V) standard aqueous solutions and successfully applied to the determination of As(III) and As(V) in river water samples with elevated content of dissolved organic carbon and suspended particulate matter with no prior sample pretreatment. Excellent relative recoveries ranging from 98% to 104% were obtained for both As(III) and As(V).
- MeSH
- arseničnany izolace a purifikace MeSH
- arsenikové přípravky chemie MeSH
- arsenitany izolace a purifikace MeSH
- chemické látky znečišťující vodu izolace a purifikace MeSH
- kalibrace MeSH
- koncentrace vodíkových iontů MeSH
- kyselina citronová chemie MeSH
- limita detekce MeSH
- průtoková injekční analýza metody MeSH
- řeky chemie MeSH
- spektrofotometrie přístrojové vybavení metody MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- MeSH
- arsen metabolismus MeSH
- parodont metabolismus MeSH
- psi MeSH
- radiometrie MeSH
- radionuklidy MeSH
- zubní dřeň metabolismus MeSH
- zvířata MeSH
- Check Tag
- psi MeSH
- zvířata MeSH
The subject of the study was the ecological and human health consequences of environmental pollution from emissions arising from burning local coal with an arsenic content ranging from 900 to 1,500 g/tonne of dry substance. The first indication of environmental pollution by arsenic-containing emissions was the mass extinction of honeybee colonies. The neurotoxic and carcinogenic aspects of arsenic exposure were followed. On using a group diagnostics approach, significant hearing losses were detected in exposed children in both air and bone conduction audiometry at high frequency range (4,000 and 8,000 Hz, respectively). Exposure assessment of the local population of the Prievidza district, Central Slovakia, was based on biological monitoring. The criterion of higher exposure was arsenic content in hair exceeding concentrations of 3 microg/g of hair. In a 7.5-km radius of the exposed region, live about two-tenths of the district population who were considered as "exposed" and rest of the district served as the "reference" population. The subject of our analysis was a database of 1,503 non-melanoma skin cancer (NMSC) cases (756 in men and 747 in women) collected from 1977 to 1996 in the Prievidza district, Central Slovakia (population approximately 125,000). The age standardized incidence of NMSC (each confirmed by histological examination) in non-occupational settings ranged from 45.9 to 93.9 in men and from 34.6 to 81.4 in women. Analysis of our data demonstrates a positive correlation between human cumulative exposure to arsenic and incidence of NMSC.
- MeSH
- arsen analýza toxicita MeSH
- časové faktory MeSH
- databáze faktografické MeSH
- elektrárny MeSH
- financování organizované MeSH
- hodnocení rizik MeSH
- incidence MeSH
- látky znečišťující vzduch analýza otrava MeSH
- lidé MeSH
- monitorování životního prostředí metody MeSH
- nádory kůže epidemiologie chemicky indukované MeSH
- otrava arsenem epidemiologie patofyziologie MeSH
- sexuální faktory MeSH
- uhlí MeSH
- věkové rozložení MeSH
- vlasy, chlupy chemie MeSH
- vystavení vlivu životního prostředí škodlivé účinky MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Geografické názvy
- Slovenská republika MeSH
Arsenic is a non-essential element in plant nutrition. However, As was detected in many agricultural plants, where it may pose a serious health hazard for next members of the food chain. This review presents the recent knowledge of As uptake, metabolism and transport in plants. Arsenates are taken up by phosphate transporters while arsenites are transported to cells via aquaporins located on cytoplasmic membranes. Inside the root cells, arsenates are rapidly reduced with arsenate reductase or some non-specific reducing agents. They are complexed by phytochelatins and then transported to vacuoles. Hyperaccumulators, instead of producing phytochelatins to detoxify As, transport free As to shoots and, similarly, accumulate it in vacuoles. The review highlights the importance of research on As phytotoxicity evaluation in terms of its impact on agricultural production. Exposure to As results in growth and reduction of biomass production, inhibition of germination, impaired nutrient uptake and adverse effects on photosynthetic processes. These aspects are discussed in the review.
Arsenic (As) pollution is a serious concern worldwide. Recent studies under environmentally relevant conditions revealed that, in the aquatic plant Ceratophyllum demersum, pigments are the first observable target of toxicity, prior to any effect on photosynthetic parameters or to oxidative stress. Lethal toxicity was initiated by a change of As species and their distribution pattern in various tissues. Here, the localization of As was investigated at the subcellular level through X-ray fluorescence using a submicron beam and a Maia detector. Further, it was possible to obtain useful tissue structural information from the ratio of the tomogram of photon flux behind the sample to the tomogram of Compton scattering. The micro-X-ray fluorescence tomograms showed that As predominantly accumulated in the nucleus of the epidermal cells in young mature leaves exposed to sublethal 1 µM As. This suggests that As may exert toxic effects in the nucleus, for example, by interfering with nucleic acid synthesis by replacing phosphorous with As. At higher cellular concentrations, As was mainly stored in the vacuole, particularly in mature leaves. An analysis of precursors of chlorophyll and degradation metabolites revealed that the observed decrease in chlorophyll concentration was associated with hindered biosynthesis, and was not due to degradation. Coproporphyrinogen III could not be detected after exposure to only 0.5 µM As. Levels of subsequent precursors, for example, protoporphyrin IX, Mg-protoporphyrin, Mg-protoporphyrin methyl ester, and divinyl protochlorophyllide, were significantly decreased at this concentration as well, indicating that the pathway was blocked upstream of tetrapyrrole synthesis.
The As concentrations, along with 34 other elements, and the As speciation were investigated in wild-grown samples of the parasitic mushroom Tolypocladium ophioglossoides with inductively coupled plasma mass spectrometry (ICPMS) and high performance liquid chromatography coupled to ICPMS. The As concentrations were 0.070-3.44 mg kg-1 dry mass. More remarkable was the As speciation, where up to 56% of the extracted As were found to be an unknown As species, which was marginally retained under anion- and also cation-exchange conditions. After testing several different chromatographic settings, the compound was finally isolated and identified as 2-(sulfoxyethyl) trimethylarsonium ion (in short: arsenocholine-O-sulfate) with high resolution mass spectrometry. The compound was synthesized and further quantified in all investigated samples via ion-pair chromatography coupled to ICPMS. In addition to the high abundance of arsenocholine-O-sulfate in T. ophioglossoides, small amounts of this As species were also detected in one sample of the host mushroom, Elaphomyces asperulus. In a sample of another parasitic mushroom, Ophiocordyceps sinensis, arsenocholine-O-sulfate could not be detected, but the main species was another unknown compound that was oxidized to inorganic As(V) with hydrogen peroxide. This is the first discovery of arsenocholine-O-sulfate in nature. It is possible that it is present in many other organisms, at least in low concentrations, and just has not been detected there yet because of its unusual chromatographic behavior. The existence of arsenocholine-O-sulfate brings up questions again about the biotransformation pathways of As in the environment and the specific behavior of fungi.
OBJECTIVE: This study aims to study the preparation method of arsenic trioxide (As2O3) polylactic-co-glyconlic acid (PLGA) microspheres and 10-hydroxycamptothecin (HCPT) PLGA microspheres and explore their therapeutic effects as embolic agents for VX2 hepatocellular carcinoma in rabbits. METHODS: As2O3 and HCPT PLGA microspheres were prepared by multiple emulsion solvent evaporation method. Scanning electron microscopy (SEM) and particle size distribution were used to analyze the morphology, the drug sustained release ability was observed by the release of microspheres in vitro. The rabbit model of VX2 hepatocellular carcinoma was established and the hepatocellular carcinoma was treated with combined microspheres. The therapeutic effects were detected by qPCR, western blotting, HE staining and immunohistochemical methods. RESULTS: The PLGA microspheres loaded with As2O3 and HCPT were successfully prepared by optimizing the ratio. The particle size was between 30 and 50 μm. In vitro release results showed that PLGA microspheres loaded with As2O3 released completely in 10 days and PLGA microspheres loaded with HCPT released completely in 12 days. Western blotting and qPCR results showed that the expression of ALDH1A1 and Nanog decreased significantly in treatment group. HE staining and immunohistochemical analysis showed that the expression of CD31, HIF and VEGF decreased significantly and the apoptosis of tissues was obvious. CONCLUSION: The combination of As2O3 and HCPT PLGA microspheres as embolization for VX2 hepatocellular carcinoma in rabbits has significant therapeutic effect.
- MeSH
- hepatocelulární karcinom farmakoterapie MeSH
- kamptothecin aplikace a dávkování analogy a deriváty MeSH
- kopolymer kyseliny glykolové a mléčné * MeSH
- králíci MeSH
- mikrosféry * MeSH
- modely nemocí na zvířatech MeSH
- nádory jater farmakoterapie MeSH
- oxid arsenitý aplikace a dávkování MeSH
- protinádorové látky aplikace a dávkování MeSH
- zvířata MeSH
- Check Tag
- králíci MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
