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  • 1
    Electronic Resource
    Electronic Resource
    An origin for arsenobetaine involving bacterial formation of an arsenic–carbon bond (2004)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 235 (2004), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Lysed-cell extract of a Pseudomonas sp. was shown to catalyse bioconversion of dimethylarsinoylacetate to arsenobetaine and dimethylarsinate. Provision of the universal methyl donor S-adenosylmethionine to bioconversion mixtures promoted both the rate and extent of arsenobetaine formation. These findings suggest that in the proposed biosynthesis of arsenobetaine from dimethylarsinoylethanol, oxidation (i.e. the formation of the carboxymethyl group of dimethylarsinoylacetate) would precede the reduction and methylation at the arsenic atom. The presence of enzyme(s) capable of methylating dimethylarsinoylacetate in a bacterial isolate from marine mussel (Mylitus edulis), highlights a possible direct involvement of prokaryotic organisms in the biosynthesis of organoarsenic compounds within marine animals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1574-6968.2004.tb09572.x
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  • 2
    Electronic Resource
    Electronic Resource
    Speciation of arsenic compounds by coupling high-performance liquid chromatography with inductively coupled plasma mass spectrometry (1998)
    Springer
    Microchimica acta 130 (1998), S. 71-79 
    Details
    ISSN: 1436-5073
    Keywords: arsenic ; speciation ; liquid chromatography ; ICP-MS
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract There is considerable evidence that toxicity and physiological behavior of arsenic depends on its chemical forms. Arsenic speciation became therefore the subject of increasing interest in recent years. A sensitive method for the determination of arsenic species has been developed. The proposed procedure involves the use of high-performance liquid chromatography and inductively coupled plasma mass spectrometry (HPLC-ICP-MS). Six arsenic compounds were separated by anion-exchange chromatography with isocratic elution using tartaric acid as mobile phase with an elution order: arsenocholine, arsenobetaine, dimethylarsinic acid, methylarsonic acid, arsenous acid and arsenic acid. The chromatographic parameters affecting the separation of the arsenic species were optimized. Analytical characterization of the method has been realized with standard solutions. The detection limits for six arsenic compounds were from 0.04 to 0.6 μg/L as As element. The repeatability (expressed by R.S.D) was better than 7% for all investigated compounds. The HPLC-ICP-MS system was successfully applied to the determination of arsenic compounds in environmental and biological samples in μg/L level.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01254593
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  • 3
    Electronic Resource
    Electronic Resource
    Studies on the voltammetric behaviour of a 2-mercaptoimidazole containing carbon paste electrode: determination of traces of silver (1994)
    Springer
    Fresenius' Zeitschrift für analytische Chemie 348 (1994), S. 736-741 
    Details
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The voltammetric behaviour of a 2-mercaptoimidazole (2-MI) containing carbon paste electrode was studied. When mixed to carbon paste as an electrode modifier, 2-MI can be reduced at negative potentials (−1 V vs. SCE), but it does not give a response in the potential range where Ag(0) is oxidized to Ag(I). Silver could be accumulated from 0.1 mol l−1 acetate buffer onto a 2-MI modified carbon paste electrode without a potential applied; after medium exchange, it was reduced at −1 V vs. SCE in 0.1 mol l−1 acetate buffer solution and determined by differential pulse anodic stripping voltammetry. With suitable preconcentration times, the detection limit was 0.1 μg l−1; a linear relation between current and concentration was found to exist within a range of 0.5 to 1000 μg l−1. In the presence of EDTA, common metal ions have no or only little effect on the voltammetric determination of silver.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00323695
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  • 4
    Electronic Resource
    Electronic Resource
    Can Humans Metabolize Arsenic Compounds to Arsenobetaine? (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 11 (1997), S. 327-335 
    Details
    ISSN: 0268-2605
    Keywords: arsenic ; urine ; HPLC-ICP-MS ; arsenobetaine ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Arsenic compounds were determined in 21 urine samples collected from a male volunteer. The volunteer was exposed to arsenic through either consumption of codfish or inhalation of small amounts of (CH3)3As present in the laboratory air. The arsenic compounds in the urine were separated and quantified with an HPLC-ICP-MS system equipped with a hydraulic high-pressure nebulizer. This method has a determination limit of 0.5 μg As dm-3 urine. To eliminate the influence of the density of the urine, creatinine was determined and all concentrations of arsenic compounds were expressed in μg As g-1 creatinine. The concentrations of arsenite, arsenate and methylarsonic acid in the urine were not influenced by the consumption of seafood. Exposure to trimethylarsine doubled the concentration of arsenate and increased the concentration of methylarsonic acid drastically (0.5 to 5 μg As g-1 creatinine). The concentration of dimethylarsinic acid was elevated after the first consumption of fish (2.8 to 4.3 μg As g-1 creatinine), after the second consumption of fish (4.9 to 26.5 μg As g-1 creatinine) and after exposure to trimethyl- arsine (2.9 to 9.6 μg As g-1 creatinine). As expected, the concentration of arsenobetaine in the urine increased 30- to 50-fold after the first consumption of codfish. Surprisingly, the concentration of arsenobetaine also increased after exposure to trimethylarsine, from a background of approximately 1 μg As g-1 creatinine up to 33.1 μg As g-1 creatinine. Arsenobetaine was detected in all the urine samples investigated. The arsenobetaine in the urine not ascribable to consumed seafood could come from food items of terrestrial origin that - unknown to us - contain arsenobetaine. The possibility that the human body is capable of metabolizing trimethyl- arsine to arsenobetaine must be considered. © 1997 by John Wiley & Sons, Ltd.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Arsenic Compounds in Terrestrial Organisms I: Collybia maculata, Collybia butyracea and Amanita muscaria from Arsenic Smelter Sites in Austria (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 11 (1997), S. 289-296 
    Details
    ISSN: 0268-2605
    Keywords: mushrooms ; arsenic ; arsenobetaine ; arsenocholine ; hydraulic high-pressure nebulizer ; HPLC-HHPN-ICP-MS ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Arsenic Compounds in Terrestrial Organisms II: Arsenocholine in the Mushroom Amanita muscaria (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 11 (1997), S. 459-470 
    Details
    ISSN: 0268-2605
    Keywords: arsenocholine ; mushroom ; arsenobetaine ; arsenic compounds ; hydraulic high-pressure nebulizer ; ICP-MS ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Arsenic compounds were identified and quantified in the mushroom Amanita muscaria, collected close to a facility that had roasted arsenic ores. The powdered dried mushrooms were extracted with methanol/water (9:1), the extracts were concentrated and the concentrates were dissolved in water. The resulting solutions were chromatographed on anion-exchange, cation-exchange and reversed- phase columns. Arsenic was detected on-line with an ICP-MS detector equipped with a hydraulic high-pressure nebulizer. Arsenite, arsenate, dimethylarsinic acid and the tetramethylarsonium cation were minor arsenic compounds (∼2% each of the total 22 mg kg-1 dry mass), and arsenobetaine, arsenocholine (∼15% each) and several unidentified arsenic compounds (∼60%) were the major arsenic compounds in Amanita muscaria. The presence of arsenocholine (detected for the first time in a terrestrial sample) was ascertained by matching retention times in the anion-exchange, cation- exchange and reversed-phase chromatograms with the retention time of synthetic arsenocholine bromide and chromatographing extracts spiked with arsenocholine bromide. © 1997 John Wiley & Sons, Ltd.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Speciation and health risk considerations of arsenic in the edible mushroom Laccaria amethystina collected from contaminated and uncontaminated locations (1998)
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 12 (1998), S. 285-291 
    Details
    ISSN: 0268-2605
    Keywords: mushroom ; arsenic speciation ; HPLC-ICP-MS ; dimethylarsinic acid ; arsenobetaine ; trimethylarsine oxide ; toxicological evaluation ; soil contamination ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Samples of the edible mushroom Laccaria amethystina, which is known to accumulate arsenic, were collected from two uncontaminated beech forests and an arsenic-contaminated one in Denmark. The total arsenic concentration was 23 and 77 μg  As g-1 (dry weight) in the two uncontaminated samples and 1420 μg As g-1 in the contaminated sample. The arsenic species were liberated from the samples using focused microwave-assisted extraction, and were separated and detected by anion- and cation-exchange high-performance liquid chromatography with an inductively coupled plasma mass spectrometer as arsenic-selective detector. Dimethylarsinic acid accounted for 68-74%, methylarsonic acid for 0.3-2.9%, trimethylarsine oxide for 0.6-2.0% and arsenic acid for 0.1-6.1% of the total arsenic. The unextractable fraction of arsenic ranged between 15 and 32%. The results also showed that when growing in the highly arsenate-contaminated soil (500-800 μg As g-1) the mushrooms or their associated bacteria were able to biosynthesize dimethylarsinic acid from arsinic acid in the soil. Furthermore, arsenobetaine and trimethylarsine oxide were detected for the first time in Laccaria amethystina. Additionally, unidentified arsenic species were detected in the mushroom. The finding of arsenobetaine and trimethylarsine oxide in low amounts in the mushrooms showed that synthesis of this arsenical in nature is not restricted to marine biota. In order to minimize the toxicological risk of arsenic to humans it is recommended not to consume Laccaria amethystina mushrooms collected from the highly contaminated soil, because of a genotoxic effect of dimethylarsinic acid observed at high doses in animal experiments. © 1998 John Wiley & Sons, Ltd.No Abstract.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Arsenic compounds in terrestrial organisms. III: Arsenic compounds in Formica from an old arsenic smelter site (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 11 (1997), S. 859-867 
    Details
    ISSN: 0268-2605
    Keywords: Formica sp. ; ants ; arsenobetaine ; arsenic compounds ; HPLC-HHPN-ICP-MS ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Total arsenic concentrations in the freeze-dried pulverized ants (Formica sp.) and material from an ant-hill collected at a former arsenic roasting facility were determined by inductively coupled plasma mass spectrometry (ICP-MS) after microwave digestion with nitric acid and hydrogen peroxide. The ants contained 12.6±0.9 mg As/kg dry mass, the ant-hill material 5420±90 mg As/kg dry mass. Total arsenic concentrations in needles of Picea abies and Larix decidua (spruce and larch needles) were also determined, because needles are the main constituents of the upper layer of ant-hill material. Needles of Picea abies contained 1.17 mg As/kg dry mass and needles of Larix decidua 3.71 mg As/kg. The Formica sp. and ant-hill material were extracted with water or methanol/water (9:1). The extracts were chromatographed on a cation-exchange and an anion-exchange column. Water extracted 20% of the arsenic from the ants and only 3% from the ant-hill material. With methanol/water (9:1) only 7% of the arsenic was released by the ants and 0.5% by the ant-hill material. The arsenic compounds in the column effluents that were introduced into the plasma via a hydraulic high-pressure nebulizer (HHPN) were quantified on-line by ICP-MS. Arsenite and arsenate were the major arsenic compounds in the extract. Dimethylarsinic acid and traces of methylarsonic acid and arsenobetaine were also detected. The extracts of the ant-hill material contained the same compounds. Additionally, traces of trimethylarsine oxide were found. The presence of arsenobetaine was confirmed by spiking an extract of the ants with synthetic arsenobetaine bromide. © 1997 John Wiley & Sons, Ltd.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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