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Kevin A. Francesconi - One of the best experts on this subject based on the ideXlab platform.
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arsenosugar phospholipids and arsenic hydrocarbons in two species of brown macroalgae
Environmental Chemistry, 2012Co-Authors: Sara Garcia Salgado, Georg Raber, Reingard Raml, Christoph Magnes, Kevin A. FrancesconiAbstract:Environmental context Although Organoarsenic Compounds occur in marine organisms at high concentrations, the origin and role of these Compounds is unknown. Arsenic-containing lipids (arsenolipids) are newly discovered Compounds in fish. We identify a range of arsenolipids in algae and propose that algae are the origin of these unusual arsenic Compounds in marine ecosystems. Abstract Fourteen arsenolipids, including 11 new Compounds, were identified and quantified in two species of brown algae, Wakame (Undaria pinnatifida) and Hijiki (Hizikia fusiformis), by high resolution mass spectrometry, high performance liquid chromatography–mass spectrometry and gas chromatography–mass spectrometry. Both algal species contained arsenosugar-phospholipids as the major type of arsenolipid, and arsenic-hydrocarbons were also significant components, particularly in Hijiki. The origin of the various arsenolipids, and the possible significance of their relative quantities, is briefly discussed.
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arsenic containing lipids are natural constituents of sashimi tuna
Environmental Science & Technology, 2010Co-Authors: Mojtaba S Taleshi, John S. Edmonds, Walter Goessler, Georg Raber, Maria Jos Ruizchancho, Kenneth B Jensen, Kevin A. FrancesconiAbstract:Arsenic occurs naturally in many types of seafood as water- and fat-soluble Organoarsenic Compounds. Although water-soluble Compounds have been well characterized, the fat-soluble Compounds, so-called arsenolipids, have until recently remained unknown. We report that sashimi-grade tuna fish, with a total arsenic content of 5.9 μg of As/g dry mass, contains approximately equal quantities of water- and fat-soluble arsenic. The water-soluble arsenic comprised predominantly arsenobetaine (>95%) with a trace of dimethylarsinate. Two fat-soluble Compounds, which together accounted for about 40% of the lipid-arsenic, were isolated and characterized. The first was identified as 1-dimethylarsinoylpentadecane [(CH3)2As(O)(CH2)14CH3] by comparison of HPLC/mass spectrometric data and accurate mass data with those of an authenticated synthesized standard. The second arsenolipid was postulated as 1-dimethylarsinoyl all-cis-4,7,10,13,16,19-docosahexane from mass spectrometric data and analogy with non-arsenic-containing...
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a novel arsenical in clam kidney identified by liquid chromatography electrospray ionisation mass spectrometry
Rapid Communications in Mass Spectrometry, 2001Co-Authors: Kevin A. Francesconi, John S. EdmondsAbstract:Kidneys of clams of the genus Tridacna accumulate metabolic products from symbiotic unicellular algae that grow in the mantles of the clams. These metabolites include Organoarsenic Compounds that are biosynthesised by algae from arsenate in seawater. The arsenic Compounds in aqueous extracts of the kidney of the giant clam T. derasa were investigated by liquid chromatography/electrospray ionisation mass spectrometry. About 50% of the water-soluble arsenic was present as dimethylarsinoylribosides and dimethylarsinate which are common algal metabolites. The major compound in the kidney (50% of water-soluble arsenic) was identified as a 5-dimethylarsinoyl-2,3,4-trihydroxycarboxylic acid, a new natural product. Copyright © 2001 John Wiley & Sons, Ltd.
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liquid chromatography electrospray mass spectrometry with variable fragmentor voltages gives simultaneous elemental and molecular detection of arsenic Compounds
Rapid Communications in Mass Spectrometry, 2000Co-Authors: Soren N Pedersen, Kevin A. FrancesconiAbstract:A single quadrupole high performance liquid chromatography electrospray mass spectrometry system with a variable fragmentor voltage facility was used in the positive ion mode for simultaneous recording of elemental and molecular mass spectral data for arsenic Compounds. The method was applicable to the seven Organoarsenic Compounds tested: four arsenic-containing carbohydrates (arsenosugars), a quaternary arsonium compound (arsenobetaine), dimethylarsinic acid, and dimethylarsinoylacetic acid. It was not suitable for the two inorganic arsenic species arsenite and arsenate. In the case of arsenosugars, qualifying ion data for a characteristic common fragment (m/z 237) was also simultaneously obtained. The method was used to identify and quantify the major arsenosugars in crude extracts of two brown algae. Copyright © 2000 John Wiley & Sons, Ltd.
Mawrong Lee - One of the best experts on this subject based on the ideXlab platform.
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a novel method of ultrasound assisted dispersive liquid liquid microextraction coupled to liquid chromatography mass spectrometry for the determination of trace Organoarsenic Compounds in edible oil
Analytica Chimica Acta, 2011Co-Authors: Weixun Wang, Tzungjie Yang, Tingting Jong, Mawrong LeeAbstract:A novel approach, ultrasound-assisted dispersive liquid-liquid microextraction combined with liquid chromatography-mass spectrometry (UA-DLLME with LC-MS) is demonstrated to be quite useful for the determination of trace amounts of Organoarsenic Compounds in edible oil. The Organoarsenic Compounds studied include dimethylarsinic acid (DMA), monomethylarsonic acid (MMA) and 3-nitro-4-hydroxyphenyl arsenic acid (Roxarsone). Orthogonal array experimental design (OAD) was utilized to investigate the parameter space of conditions for UA-DLLME. The optimum conditions were found to be 4 min of ultrasonic extraction using 1.25 mL of mixed solvent with 50 μL of buffer solution. Under these optimal conditions, the linear range was from 10 ng g(-1) to 500 ng g(-1) for DMA and Roxarsone, from 25 ng g(-1) to 500 ng g(-1) for MMA. Limits of detection of DMA, MMA and Roxarsone were 1.0 ng g(-1), 3.0 ng g(-1) and 5.8 ng g(-1), respectively. The precisions and recoveries also were investigated by spiking 3-level concentrations in edible oil. The recoveries obtained were over 89.9% with relative standard deviation (RSD) of 9.6%. The new approach was utilized to successfully detect trace amounts of Organoarsenic Compounds in various edible oil samples.
Kare Julshamn - One of the best experts on this subject based on the ideXlab platform.
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survey of inorganic arsenic in marine animals and marine certified reference materials by anion exchange high performance liquid chromatography inductively coupled plasma mass spectrometry
Journal of Agricultural and Food Chemistry, 2005Co-Authors: Jens Jorgen Sloth, Erik Huusfeldt Larsen, Kare JulshamnAbstract:A method for the determination of inorganic arsenic in seafood samples using high-performance liquid chromatography−inductively coupled plasma mass spectrometry is described. The principle of the method relied on microwave-assisted alkaline dissolution of the sample, which at the same time oxidized arsenite [As(III)] to arsenate [As(V)], whereby inorganic arsenic could be determined as the single species As(V). Anion exchange chromatography using isocratic elution with aqueous ammonium carbonate as the mobile phase was used for the separation of As(V) from other coextracted Organoarsenic Compounds, including arsenobetaine. The stability of Organoarsenic Compounds during the sample pretreatment was investigated, and no degradation/conversion to inorganic arsenic was detected. The method was employed for the determination of inorganic arsenic in a variety of seafood samples including fish, crustaceans, bivalves, and marine mammals as well as a range of marine certified reference materials, and the results w...
Weixun Wang - One of the best experts on this subject based on the ideXlab platform.
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a novel method of ultrasound assisted dispersive liquid liquid microextraction coupled to liquid chromatography mass spectrometry for the determination of trace Organoarsenic Compounds in edible oil
Analytica Chimica Acta, 2011Co-Authors: Weixun Wang, Tzungjie Yang, Tingting Jong, Mawrong LeeAbstract:A novel approach, ultrasound-assisted dispersive liquid-liquid microextraction combined with liquid chromatography-mass spectrometry (UA-DLLME with LC-MS) is demonstrated to be quite useful for the determination of trace amounts of Organoarsenic Compounds in edible oil. The Organoarsenic Compounds studied include dimethylarsinic acid (DMA), monomethylarsonic acid (MMA) and 3-nitro-4-hydroxyphenyl arsenic acid (Roxarsone). Orthogonal array experimental design (OAD) was utilized to investigate the parameter space of conditions for UA-DLLME. The optimum conditions were found to be 4 min of ultrasonic extraction using 1.25 mL of mixed solvent with 50 μL of buffer solution. Under these optimal conditions, the linear range was from 10 ng g(-1) to 500 ng g(-1) for DMA and Roxarsone, from 25 ng g(-1) to 500 ng g(-1) for MMA. Limits of detection of DMA, MMA and Roxarsone were 1.0 ng g(-1), 3.0 ng g(-1) and 5.8 ng g(-1), respectively. The precisions and recoveries also were investigated by spiking 3-level concentrations in edible oil. The recoveries obtained were over 89.9% with relative standard deviation (RSD) of 9.6%. The new approach was utilized to successfully detect trace amounts of Organoarsenic Compounds in various edible oil samples.
Jens Jorgen Sloth - One of the best experts on this subject based on the ideXlab platform.
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survey of inorganic arsenic in marine animals and marine certified reference materials by anion exchange high performance liquid chromatography inductively coupled plasma mass spectrometry
Journal of Agricultural and Food Chemistry, 2005Co-Authors: Jens Jorgen Sloth, Erik Huusfeldt Larsen, Kare JulshamnAbstract:A method for the determination of inorganic arsenic in seafood samples using high-performance liquid chromatography−inductively coupled plasma mass spectrometry is described. The principle of the method relied on microwave-assisted alkaline dissolution of the sample, which at the same time oxidized arsenite [As(III)] to arsenate [As(V)], whereby inorganic arsenic could be determined as the single species As(V). Anion exchange chromatography using isocratic elution with aqueous ammonium carbonate as the mobile phase was used for the separation of As(V) from other coextracted Organoarsenic Compounds, including arsenobetaine. The stability of Organoarsenic Compounds during the sample pretreatment was investigated, and no degradation/conversion to inorganic arsenic was detected. The method was employed for the determination of inorganic arsenic in a variety of seafood samples including fish, crustaceans, bivalves, and marine mammals as well as a range of marine certified reference materials, and the results w...