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1.
Plants and soil collected above an ore vein in Gasen (Austria) were investigated for total arsenic concentrations by inductively coupled plasma mass spectrometry (ICP‐MS). Total arsenic concentrations in all samples were higher than those usually found at non‐contaminated sites. The arsenic concentration in the soil ranged from ∼700 to ∼4000 mg kg−1 dry mass. Arsenic concentrations in plant samples ranged from ∼0.5 to 6 mg kg−1 dry mass and varied with plant species and plant part. Examination of plant and soil extracts by high‐performance liquid chromatography–ICP‐MS revealed that only small amounts of arsenic (<1%) could be extracted from the soil and the main part of the extractable arsenic from soil was inorganic arsenic, dominated by arsenate. Trimethylarsine oxide and arsenobetaine were also detected as minor compounds in soil. The extracts of the plants (Trifolium pratense, Dactylis glomerata, and Plantago lanceolata) contained arsenate, arsenite, methylarsonic acid, dimethylarsinic acid, trimethylarsine oxide, the tetramethylarsonium ion, arsenobetaine, and arsenocholine (2.5–12% extraction efficiency). The arsenic compounds and their concentrations differed with plant species. The extracts of D. glomerata and P. lanceolata contained mainly inorganic arsenic compounds typical of most other plants. T. pratense, on the other hand, contained mainly organic arsenicals and the major compound was methylarsonic acid. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

2.
Chlorella vulgaris was cultivated in a growth medium containing arsenate concentration of <0.01, 10, 100 and 1000 mg l?1. Illumination was carried out in 12 h cycles for 5 days. The health status of the culture was monitored by continuous pH and dissolved oxygen (DO) readings. Destructive sampling was used for the determination of biomass, chlorophyll, total arsenic and arsenic species. The chlorophyll a content, the DO and pH cycles were not significantly different for the different arsenate concentrations in the culture. In contrast, biomass production was significantly (p < 0.05) increased for the arsenic(V) treatment at 1000 mg l?1 compared with 100 mg l?1. The arsenic concentration in the algae increased with the arsenate concentration in the culture. However, the bioconcentration factor decreased a hundred‐fold with increase of arsenate from the background level to 1000 mg l?1. The arsenic species were identified by using strong anion‐exchange high‐performance liquid chromatography–inductively coupled plasma mass spectrometry analysis after methanol/water (1 : 1) extraction. The majority (87–100%) of the extractable arsenic was still arsenate; arsenite was found to be between 1 and 6% of total extractable arsenic in the algae. In addition to dimethylarsinic acid, one unknown arsenical (almost co‐eluting with methylarsonic acid) and three different arsenosugars have been identified for the first time in C. vulgaris growing in a culture containing a mixture of antibiotics and believed to be axenic. The transformation to arsenosugars in the algae is not dependent on the arsenate concentration in the culture and varies between 0.2 and 5% of total accumulated arsenic. Although no microbiological tests for bacterial contamination were made, this study supports the hypothesis that algae, and not associated bacteria, produce the arsenosugars. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

3.
In this work three mild extraction agents for determination of plant-available fractions of elements in soil were evaluated for arsenic speciation in soil samples. Pepper (Capsicum annum, L.) var. California Wonder was cultivated in pots, and aqueous solutions of arsenite, arsenate, methylarsonic acid, and dimethylarsinic acid, at a concentration of 15 mg As kg–1 soil, were added at the beginning of the experiment. Control pots (untreated) were also included. Deionized water, 0.01 mol L–1 CaCl2, and 0.05 mol L–1 (NH4)2SO4 were used to extract the plant-available fraction of the arsenic compounds in soil samples collected during the vegetation period of the plants. Whereas in control samples the extractable arsenic fraction did not exceed 1% of total arsenic content, soil amendment by arsenic compounds resulted in extraction of larger amounts, which varied between 1.4 and 8.1% of total arsenic content, depending on soil treatment and on the extracting agent applied. Among arsenic compounds determined by HPLC–ICPMS arsenate was predominant, followed by small amounts of arsenite, methylarsonic acid, and dimethylarsinic acid, depending on the individual soil treatment. In all the experiments in which methylarsonic acid was added to the soil methylarsonous acid was detected in the extracts, suggesting that the soil bacteria are capable of reducing methylarsonic acid before a further methylation occurs. No significant differences were observed between analytical data obtained by using different extraction procedures.  相似文献   

4.
Pooled livers and pooled kidneys from rats or mice were homogenized and spiked with arsenite or arsenate in the concentration range 1.3–20 μmol dm?3. Methylarsenic and dimethylarsenic compounds were determined by the hydride generation technique in the homogenates after a 90 min incubation at 37°C. The rat homogenates methylated arsenite and arsenate more efficiently than the mouse homogenates. Monomethylated arsenic was present in larger amounts than dimethylated arsenic in the rat homogenates. In the absence of reduced glutathione (GSH), no methylation occurred. Addition of GSH promoted monomethylation and dimethylation, whereas dithiothreitol and mercaptoethanol (10 mmol dm?3) fostered only monomethylation. The amounts of monomethylated arsenic in the rat liver homogenates increased with increasing arsenite concentration (1.3–20 μmol dm?3) however, the percentage of arsenic that had been methylated decreased. A similar trend, but with much less monomethylarsenic formed, was observed for arsenate-spiked homogenates. Rat kidney homogenates methylated arsenite and arsenate to a much smaller extent than rat liver homogenates. The Km values for the monomethylation in rat liver homogenates were found to be 5.3 μmol dm?3 for arsenite and 59 μmol dm?3 for arsenate.  相似文献   

5.
Arsenic contamination of groundwater has long been reported in the Mushidabad district of West Bengal, India. We visited 13 arsenic‐affected families in the Makrampur village of the Beldanga block in Mushidabad during 18–21 December 2001 and collected five shallow tubewell‐water samples used general household purposes, four deep tubewell‐water samples used for drinking and cooking purposes, and 44 urine samples from those families. The arsenic concentrations in the five shallow tubewell‐water samples ranged from 18.0 to 408.4 ppb and those in the four deep tubewell‐water samples were from 5.2 to 9.6 ppb. The average arsenite (arsenic(III)), dimethylarsinic acid (DMA), monomethylarsonic acid (MMA) and arsenate (arsenic(V)) in urine were 28.7 ng mg?1, 168.6 ng mg?1, 25.0 ng mg?1 and 4.6 ng mg?1 creatinine respectively. The average total arsenic was 227.0 ng mg?1 creatinine. On comparison of the ratio of (MMA + DMA) to total arsenic, the average proportion was 86.7 ± 9.2% (mean plus/minus to residual standard deviation, n = 43). The exception was data for one boy, whose proportion was 8.0%. One woman excreted the highest total arsenic, at 2890.0 ng mg?1 creatinine. When using 43 of the urine samples (the exception being the one sample obtained from the boy) there were significantly positive correlations (p < 0.01) between arsenic(III) and MMA, between arsenic(III) and DMA and between MMA and DMA. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

6.
Eight extraction agents (water, methanol–water mixtures in various ratios, methanol, a 20 mmol l?1 ammonium phosphate buffer, and a methanol–phosphate buffer) were tested for the extraction of arsenic compounds from fruits, stems + leaves, and roots of pepper plants grown on soil containing 17.2 mg kg?1 of total arsenic. The arsenic compounds in the extracts were determined using high‐performance liquid chromatography–hydride generation inductively coupled plasma mass spectrometry. Whereas pure water was the most effective extraction agent for fruits (87 ± 3.3% extraction yield) and roots (96 ± 0.6% extraction yield), the 20 mM ammonium phosphate buffer at pH 6 extracted about 50% of the arsenic from stems + leaves. Decreasing extractability of the arsenic compounds was observed with increasing methanol concentrations for all parts of the pepper plant. In pepper fruits, arsenic(III), arsenic(V), and dimethylarsinic acid (DMA) were present (25%, 37%, and 39% respectively of the extractable arsenic). Arsenic(V) was the major compound in stems + leaves and roots (63% and 53% respectively), followed by arsenic(III) representing 33% and 42% respectively, and small amounts (not exceeding 5%) of DMA and methylarsonic acid were also detected. Hence, for a quantitative extraction of arsenic compounds from different plant tissues the extractant has to be optimized individually. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

7.
Humans are exposed to arsenic by inhalation and ingestion and are therefore may be affected by its toxicity. Arsenic may enter the human body by inhalation and ingestion. Cooking may alter the contents and chemical forms of arsenic. The determination of arsenic species in Lentinus edodes after microwave blanching was performed by high-performance liquid chromatography–inductively coupled plasma–mass spectrometry. Using a physiologically based extraction, the bioaccessibility of arsenic species in raw L. edodes and microwave blanching treated L. edodes were determined after the simulated gastrointestinal digestion. The arsenate (AsV), arsenite (AsIII), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), arsenobetaine, and arsenocholine did not undergo decomposition and transformation in this study. Furthermore, the total contents of arsenic in L. edodes samples were in the range of 0.1378?±?0.0044–0.2347?±?0.0144?mg/kg. Approximately 3.38–43.27% were released from samples into the blanching water after various microwave blanching treatments. The oxidation of AsIII and demethylation of DMA and MMA were observed in L. edodes during digestion, increasing the likelihood of arsenic toxicity in the liver. The health risk for arsenic in L. edodes was decreased after microwave blanching because the potentially available arsenic in microwave blanching treatments L. edodes samples (83.78?±?0.9103%) were lower than those in raw L. edodes samples (88.33?±?0.7983%). L. edodes subjected to microwave blanching prior to consumption significantly decreased the total arsenic content and the risk of arsenic exposure to consumers (p?相似文献   

8.
Arsenic (As) in soils and hair collected from schools in Ron Phibun district, Nakhon Si Thammarat province, Thailand, where former tin mining operation were located, was determined by hydride generation atomic absorption spectrophotometry. The relationship between As content in soils and hair with distance from secured landfill was also investigated. Soil and hair samples were collected from 6 schools in summer (February) and rainy season (July). For soils, silt+clay (<45 µm) fraction and sand (45 µm–2 mm) fraction were analyzed. The average concentrations of arsenic in soils during summer (21.70 ± 16.79 mg/kg) and rainy season (22.45 ± 14.17 mg/kg) were at the same concentration level. The average arsenic content in hair samples was 2.24 ± 0.05 mg/kg in rainy season which was higher than 1.05 ± 0.04 mg/kg in summer. It was found that arsenic contents in hair and soils are correlated with the distance from the secured landfill. Most importantly, a positive relationship between arsenic content in hair and soil was obtained for rainy season, which indicated that arsenic in soil corresponded to arsenic in hair. The cancer risk from soils ranged from 4.48 × 10?7 to 2.06 × 10?6 indicating low carcinogenic risk to school children.  相似文献   

9.
The effects of light on arsenic accumulation of Thraustochytrium CHN‐1 were investigated. Thraustochytrium CHN‐1, when exposed to blue light from light‐emitting diodes (LEDs), accumulated arsenate added to its growth medium to a much greater extent than Thraustochytrium cells exposed to fluorescent or red light, or when cultured in the dark. Arsenic compounds in Thraustochytrium CHN‐1 were analyzed by high‐performance liquid chromatography, with an inductively coupled plasma mass spectrometer serving as an arsenic‐specific detector. Arsenate, arsenite, monomethylarsonic acid (MMAA), dimethylarsinic acid (DMAA) and arsenosugar were identified. The order of arsenic species in Thraustochytrium CHN‐1 was arsenic(V)> arsenic(III)> MMAA > DMAA at an arsenic concentration of 10 mg dm?3 in the medium in blue LED light. As it is known that blue light induces the synthesis of certain metabolites in plants and microorganisms, this indicates that the accumulation of arsenic is an active metabolic process. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

10.
许文菊  袁若  柴雅琴 《中国化学》2009,27(1):99-104
本文以2,9,16,23-四硝基酞菁铜(II) (Cu(II)TNPc) 和2,9,16,23-四氨基酞菁铜(II) (Cu(II)TAPc) 为载体制备PVC聚合膜,构建了水杨酸根选择性电极,并探讨了该电极的选择性响应性能。研究了增塑剂的性质、载体的含量及阴、阳离子添加剂对电极电位响应的影响。结果表明,基于Cu(II)TNPc为载体的PVC膜电极对水杨酸根 (Sal-) 呈现出优先选择性电位响应。具有最佳电位响应的电极的膜组成是:(w/w) 3.0% Cu(II)TNPc,67.0% o-NPOE,29.5% PVC和0.5% NaTPB。基于该组成的电极的线性响应范围为1.0×10-1-9.0×10-7 mol·L-1,检测下限为7.2×10-7 mol·L-1,斜率为-59.8±0.5 mV/decade;其响应快速,稳定性好,适宜的pH范围是3.0-7.0。并成功运用于了实际样品中水杨酸含量的测定,获得令人满意的结果。  相似文献   

11.
The influences of reactant concentrations, solvent type, acid strength, pH conditions and ionic strength on the determination of apparent gas‐phase equilibrium constants K using electrospray ionisation mass spectrometry (ESI‐MS) were elucidated. As example serves the interaction of the tripeptide glutathione (GSH) with phenylarsine oxide (PAO). It was shown that rising initial concentrations of both reactants were not adequately compensated by increasing signal intensities of the reaction products in the mass spectra. The equilibrium constant for the formation of the phenylarsenic‐substituted peptide species decreased from 1.42 × 105 ± 1.81 × 104 l µmol?1 to 1.54 × 104 ± 1.5 × 103 l µmol?1 with rising initial GSH concentrations from 1 to 10 µM at fixed PAO molarity of 50 µM . K values resulting from a series with a fixed GSH molarity of 5 µM and a PAO molarity varied from 10 to 100 µM remained in a narrower range between 4.59 × 104 ± 2.15 × 104 l µmol?1 and 1.07 × 104 ± 4.0 × 103 l µmol?1. In contrast, consumption numbers calculated from the ion intensity ratios of reaction products to the unreacted peptide were not influenced by the initial reactant concentrations. In a water–acetonitrile–acetic acid mixture (48:50:2, v:v), the consumption of 5 µ M GSH increased from 8.3 ± 1.4% to 39.6 ± 1.6% with increased molar excess of PAO from 2 to 20, respectively. The GSH consumption was considerably enhanced in a changed solvent system consisting of 25% acetonitrile and 75% 10 mM ammonium formate, pH 5.0 (v:v) up to 80% of the original peptide amount at an only threefold molar arsenic excess. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

12.
The aim of this study was to develop a method for the characterization of internal exposure to arsenic, which is thought to play a role in the development of a kidney disease, known as Balkan Endemic Nephropathy, typical for a district in Bulgaria, and to investigate whether the As body burden differs in the offspring versus control individuals. For this case study, an analytical procedure for the determination of toxicologically relevant arsenic (the sum of arsenite, arsenate, monomethylarsonate, and dimethylarsinate) in urine by batch-type hydride generation atomic absorption spectrometry was developed. Optimization experiments for levelling off the sensitivity of inorganic arsenic and its mono- and dimethylated species in dilute HCl–L-cysteine medium were performed. The limit of detection for hydride forming arsenic fraction was 0.5?ng As, i.e. 0.25?µg?L?1 in 10?mL of 1?+?4 v/v diluted urine. The relative standard deviation was typically 1.5–1.8% for aqueous solution and 2–6% for urine samples at 1.0?µg?L?1 As. The sample throughput rate was 15?h?1. No statistical correlation and cross-correlation between individuals case-control and sex at 95% confidence were found: controls (n?=?99), mean 3.5?±?2.1 (SD), range 0.9–10.4, median 3.0?µg?L?1 As and cases (n?=?102), mean 3.6?±?2.2 (SD), range 0.5–11.0, median 3.2?µg?L?1 As. On the basis of this study, arsenic can be excluded as a factor involved in BEN development.  相似文献   

13.
The arsenic species present in samples of the crayfish Procambarus clarkii caught in the area affected by the toxic mine‐tailing spill at Aznalcóllar (Seville, Southern Spain) were analyzed. The total arsenic contents ranged between 1.2 and 8.5 µg g?1 dry mass (DM). With regard to the different species of arsenic, the highest concentrations were for inorganic arsenic (0.34–5.4 µg g?1 DM), whereas arsenobetaine, unlike the situation found in marine fish products, was not the major arsenic species (0.16 ± 0.09 µg g?1 DM). Smaller concentrations were found of arsenosugars 1a (0.18 ± 0.11 µg g?1 DM), 1b (0.077 ± 0.049 µg g?1 DM), 1c (0.080 ± 0.089 µg g?1 DM), and 1d (0.14 ± 0.13 µg g?1 DM). The presence of two unknown arsenic species was revealed (U1: 0.058 ± 0.058 µg g?1 DM; U2: 0.12 ± 0.12 µg g?1 DM). No significant differences were seen with respect to the total arsenic contents between the sexes. However, significant differences in the total arsenic contents were revealed between the area affected by the spill and the area not affected, the contents being greater in the affected area. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

14.
Blue mussels (Mytilus edulis) were exposed to 100 μg As dm?3 in the form of arsenite, arsenate, methylarsonic acid, dimethylarsinic acid, arsenobetaine, arsenocholine, trimethylarsine oxide, tetramethylarsonium iodide or dimethyl-(2-hydroxyethyl)arsine oxide in seawater for 10 days. The seawater was renewed and spiked with the arsenic compounds daily. Analyses of water samples taken 24 h after spiking showed that arsenobetaine and arsenocholine had been converted to trimethylarsine oxide, whereas trimethylarsine oxide and tetramethylarsonium iodide were unchanged. Arsenobetaine was accumulated by mussels most efficienty, followed in efficiency by arsenocholine and tetramethylarsonium iodide. None of the other arsenic compounds was significantly accumulated by the mussels. Extraction of mussel tissues with methanol revealed that control mussels contained arsenobetaine, a dimethyl-(5-ribosyl)arsine oxide and an additional arsenic compound, possibly dimethylarsinic acid. Mussels exposed to arsenobetaine contained almost all their experimentally accumulated arsenic as arsenobetaine, and mussels exposed to tetramethylarsonium iodide contained it as the tetramethylarsonium compound. Mussels exposed to arsenocholine had arsenobetaine as the major arsenic compound and glycerylphosphorylarsenocholine as a minor arsenic compound in their tissues. The results show that arsenobetaine and arsenocholine are efficiently accumulated from seawater by blue mussels and that in both cases the accumulated arsenic is present in the tissues as arsenobetaine. Consequently arsenobetaine and/or arsenocholine present at very low concentrations in seawater may be responsible for the presence of arsenobetaine in M. edulis and probably also among other marine animals. The quantity of arsenobetaine accumulated by the mussels decreases with increasing concentrations of betaine. HPLC-ICP-MS was found to be very powerful for the investigation of the metabolism of arsenic compounds in biological systems.  相似文献   

15.

Herein, we measured the enthalpy relaxation of three styrene oligomers with different molecular weights (styrene oligomer with Mw?=?4.53?×?102: PSA-300, styrene oligomer with Mw?=?5.89?×?102: PSA-500, and styrene oligomer with Mw?=?1.01?×?103: PSA-1000) near their respective glass transition temperatures (Tg) using an adiabatic calorimeter. We determined the relaxation rates and the amounts of configurational enthalpy released from the temperature dependence of the temperature drift rates around Tg. Based on our experimental findings, we found the amounts of configurational enthalpy release per monomer unit to be 0.8, 3.5, and 1.6 kJ mol?1 for PSA-300, PSA-500, and PSA-1000, respectively. These values were 3.9–18 times larger than that of glycerol, which is a typical glass-forming liquid.

  相似文献   

16.
Flow injection analysis (FIA) and high-performance liquid chromatography double-focusing sector field inductively coupled plasma mass spectrometry (HPLC-DF-ICP-MS) were used for total arsenic determination and arsenic speciation of xylem sap of cucumber plants (Cucumis sativus L.) grown in hydroponics containing 2 μmol dm−3 arsenate or arsenite, respectively. Arsenite [As(III)], arsenate [As(V)] and dimethylarsinic acid (DMA) were identified in the sap of the plants. Arsenite was the predominant arsenic species in the xylem saps regardless of the type of arsenic treatment, and the following concentration order was determined: As(III) > As(V) > DMA. The amount of total As, calculated taking into consideration the mass of xylem sap collected, was almost equal for both treatments. Arsenite was taken up more easily by cucumber than arsenate. Partial oxidation of arsenite to arsenate (<10% in 48 h) was observed in the case of arsenite-containing nutrient solutions, which may explain the detection of arsenate in the saps of plants treated with arsenite.  相似文献   

17.
Abstract

A simple, sensitive and selective method for the determination of microamounts of arsenic (III) in the environment is described. Arsenic forms a yellow coloured complex with N-phenylbenzo-hydroxamic acid (PBHA) at pH 4.5-5.2 which can be extracted from chloroform. The effective molar absorptivity of As-PBHA extract is 1.1 × 1mol?1cm?1 at 410 nm. Many common ions associated with arsenic do not interfere. The effect of pH, reagent concentration and solvent is described. The arsenic in trace quantities is estimated in the industrial effluents, soil and glass samples.  相似文献   

18.

Reaction of [NH4]2[MoS4], CuCl and PyPPh2 in the solid state produces a cube-like cluster. The cluster crystallizes in the orthorhombic space group P212121 with four formula units in a cell of dimensions a = 12.8980(10) , b = 17.6820(10), c = 22.665(2) Å. Anisotropic refinement for all nonhydrogen atoms yielded the values R = 0.0397 and R w = 0.1185 for 8803 observed reflections. The structure is built up from three [Cu(Ph2PPy)]+ units bridged by MoS2? 4 to form a tetranuclear symmetrical cube-like molecule. Investigation of the third-order optical nonlinear value showed that it exhibits a considerable nonlinear absorptive and self-defocusing effect with α2 = 1.3 × 10?11 m w?1 and n 2 = ? 3.2 × 10?18 m2 w?1 in a 1.5 × 10?4 M DMF solution.  相似文献   

19.
The concentrations of total arsenic and arsenic species in the complete organism of the crayfish Procambarus clarkii and its various parts (hepatopancreas, tail, and remaining parts) were analyzed in order to discover the distribution of arsenic and its species. With this information it will be possible to establish where the chemical forms of this metalloid tend to accumulate and what risks may derive from the contents and species present in the edible parts of this crustacean. The total arsenic content in the complete organism and in the various parts analyzed ranged from 2.5 to 12 µg g?1 dry mass (DM), with inorganic arsenic representing 18 to 34% of total arsenic. The arsenical composition varied according to the part of the crayfish considered. The hepatopancreas had the highest levels of total arsenic (9.2–12 µg g?1 DM) and inorganic arsenic (2.7–3.2 µg g?1 DM). The tail (edible part) had the lowest levels of both total arsenic (2.5–2.6 µg g?1 DM) and inorganic arsenic (0.46–0.64 µg g?1 DM). The predominant organoarsenical species were the dimethylarsinoylribosides: glycerol riboside in the hepatopancreas, sulfate riboside in the tail, and sulfonate and phosphate ribosides in the remaining parts. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

20.
Three mushroom species from two old arsenic smelter sites in Austria were analyzed for arsenic compounds. The total arsenic concentrations were determined by ICP–MS. Collybia maculata contained 30.0 mg, Collybia butyracea 10.9 mg and Amanita muscaria 21.9 mg As kg−1 dry mass. The arsenic compounds extracted with methanol/water (9:1) from the dried mushroom powders were separated by HPLC on anion-exchange and reversed-phase columns and detected by ICP-MS using a hydraulic high-pressure nebulizer. In Collybia maculata almost all arsenic is present as arsenobetaine. Collybia butyracea contained mainly arsenobetaine (8.8 mg As kg−1 dry mass) and dimethylarsinic acid (1.9 mg As kg−1). Amanita muscaria contained arsenobetaine (15.1 mg As kg−1), traces of arsenite, dimethylarsinic acid and arsenate, and surprisingly arsenocholine (2.6 mg As kg−1) and a tetramethylarsonium salt (0.8 mg As kg−1). © 1997 by John Wiley & Sons, Ltd.  相似文献   

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