The Experts below are selected from a list of 204 Experts worldwide ranked by ideXlab platform
Masanori Ando - One of the best experts on this subject based on the ideXlab platform.
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high performance liquid chromatography inductively coupled plasma mass spectrometry for speciation of arsenic compounds in urine
Microchemical Journal, 2000Co-Authors: Gautam Samanta, Uttam Kumar Chowdhury, Badal Kumar Mandal, Dipankar Chakraborti, Chandra N Sekaran, Hiroshi Tokunaga, Masanori AndoAbstract:Abstract Speciation of urinary arsenic is very important to know the extent of human exposure to inorganic arsenic and also from toxicity point of view. A high performance liquid chromatography inductively coupled plasma mass spectrometry (HPLC-ICP-MS) system for speciation of arsenite, arsenate, monomethyl Arsonic Acid (MMAA), dimethyl arsenic Acid (DMAA) and arsenobetaine (AB) in a single run in urine samples has been developed. The method is based on anion exchange high performance liquid chromatography (HPLC) coupled on-line to inductively coupled plasma mass spectrometer (ICP-MS). Detection limits for the five arsenic species in urine samples are between 0.01 and 0.04 μg l −1 . To validate the method, Standard Reference Material, toxic metals in freeze-dried urine SRM 2670 containing both normal and elevated levels of arsenic have been analyzed for arsenic species. Our results of arsenic species in Standard Reference Material SRM 2670 have been compared with the results of seven other laboratories. The method has been applied to determine the arsenic species in urine samples of two groups of people from two arsenic-affected villages of two districts, out of the nine affected districts of West Bengal, India. These two groups were using arsenic-contaminated water a few years ago, but are now supposed to be using safe water for drinking and cooking, as safe sources have been installed. From their urine speciation, the nature of exposure of individuals to arsenic compound could be predicted. It is concluded that, even though these groups are using safe water, they cannot avoid, from time to time, arsenic contamination as many water sources of the surrounding areas are arsenic contaminated.
Gautam Samanta - One of the best experts on this subject based on the ideXlab platform.
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high performance liquid chromatography inductively coupled plasma mass spectrometry for speciation of arsenic compounds in urine
Microchemical Journal, 2000Co-Authors: Gautam Samanta, Uttam Kumar Chowdhury, Badal Kumar Mandal, Dipankar Chakraborti, Chandra N Sekaran, Hiroshi Tokunaga, Masanori AndoAbstract:Abstract Speciation of urinary arsenic is very important to know the extent of human exposure to inorganic arsenic and also from toxicity point of view. A high performance liquid chromatography inductively coupled plasma mass spectrometry (HPLC-ICP-MS) system for speciation of arsenite, arsenate, monomethyl Arsonic Acid (MMAA), dimethyl arsenic Acid (DMAA) and arsenobetaine (AB) in a single run in urine samples has been developed. The method is based on anion exchange high performance liquid chromatography (HPLC) coupled on-line to inductively coupled plasma mass spectrometer (ICP-MS). Detection limits for the five arsenic species in urine samples are between 0.01 and 0.04 μg l −1 . To validate the method, Standard Reference Material, toxic metals in freeze-dried urine SRM 2670 containing both normal and elevated levels of arsenic have been analyzed for arsenic species. Our results of arsenic species in Standard Reference Material SRM 2670 have been compared with the results of seven other laboratories. The method has been applied to determine the arsenic species in urine samples of two groups of people from two arsenic-affected villages of two districts, out of the nine affected districts of West Bengal, India. These two groups were using arsenic-contaminated water a few years ago, but are now supposed to be using safe water for drinking and cooking, as safe sources have been installed. From their urine speciation, the nature of exposure of individuals to arsenic compound could be predicted. It is concluded that, even though these groups are using safe water, they cannot avoid, from time to time, arsenic contamination as many water sources of the surrounding areas are arsenic contaminated.
Mary C Carson - One of the best experts on this subject based on the ideXlab platform.
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development of an ion chromatography inductively coupled plasma mass spectrometry method to determine inorganic arsenic in liver from chickens treated with roxarsone
Journal of Agricultural and Food Chemistry, 2012Co-Authors: Sean D Conklin, Nohora Shockey, Kevin M Kubachka, Karyn D Howard, Mary C CarsonAbstract:Roxarsone, (4-hydroxy-3-nitrophenyl)Arsonic Acid, is an arsenic-containing compound that has been approved as a feed additive for poultry and swine since the 1940s; however, little information is available regarding residual arsenic species present in edible tissues. We developed a novel method for the extraction and quantification of arsenic species in chicken liver. A strongly basic solution solubilized the liver, and ultrafiltration removed macromolecules and particulate material. Ion chromatography separated the species [arsenite, arsenate, monomethylArsonic Acid, dimethylarsinic Acid, (4-hydroxy-3-aminophenyl)Arsonic Acid, (4-hydroxy-3-acetaminophenyl)Arsonic Acid, and roxarsone] in the extracts, which were then detected by inductively coupled plasma-mass spectrometry. The extraction oxidized most arsenite to arsenate. For fortification concentrations at 2 μg kg(-1) and above, recoveries ranged from 70 to 120%, with relative standard deviations from 7 to 34%. We detected roxarsone, its 3-amino and 3-acetamido metabolites, inorganic arsenic, and additional unknown arsenic species in livers from roxarsone-treated chickens. Both the originating laboratory and a second laboratory validated the method.
Stephen F Donovan - One of the best experts on this subject based on the ideXlab platform.
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lewisite metabolites in urine by solid phase extraction dual column reversed phase liquid chromatography isotope dilution tandem mass spectrometry
Journal of Analytical Toxicology, 2016Co-Authors: Jason Palcic, Janet S Jones, Lindsay E Flagg, Stephen F Donovan, Redentor A Salonga, Walter E Mock, Victor S AsirvathamAbstract:: Lewisite (2-chlorovinyldichloroarsine) is a chemical warfare agent developed during World War I. A quantitative method using solid phase extraction (SPE) followed by dual column liquid chromatography (LC)-isotope dilution tandem mass spectrometry (MS-MS) was developed for the determination of (2-chlorovinyl)Arsonic Acid (CVAOA), a metabolite of Lewisite, in human urine. The sample was treated with hydrogen peroxide to oxidize any (2-chlorovinyl)arsonous Acid (CVAA) that remained in the trivalent arsenic oxidation state. There was 1.19% (arsenic purity) of bis-(2-chlorovinyl)arsinic Acid (BCVAOA), a minor Lewisite metabolite, in the stock CVAA material. The high-throughput method qualitatively assessed BCVAOA simultaneously utilizing normal-phase silica SPE followed by reversed-phase C18 LC for an orthogonal separation. The chromatographic method results in a 5.8-min cycle time with adequate retention (k' = 2.4) of CVAOA. The mass spectrometer was operated in positive electrospray ionization mode with quantitative m/z 186.9→61.0 and confirmation 186.9→91.0 mass transitions. This selective method demonstrated linearity, accuracy and reproducibility for the clinically relevant calibration range (25-3,200 µg/L as CVAA). The method detection limit was 3.3 µg/L as CVAA from a 10 µL injection. This LC-MS-MS emergency response method has a throughput of >240 samples (2.5 extracted 96-well plates) per day.
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lewisite exposure biomarkers in urine by liquid chromatography inductively coupled plasma tandem mass spectrometry with an accelerated matrix matched stability study
Journal of Analytical Atomic Spectrometry, 2015Co-Authors: Jason Palcic, Janet S Jones, Lindsay E Flagg, Stephen F DonovanAbstract:A simple and robust LC-ICP-MS/MS method is described for quantitative analysis of human urine for (2-chlorovinyl)Arsonic Acid (CVAOA), a metabolite of Lewisite. This method oxidizes (2-chlorovinyl)arsenous Acid (CVAA) with the addition of hydrogen peroxide to measure total Lewisite-1 metabolites as CVAOA, with m/z 75 → 91 detection specific for arsenic. The percentage of CVAA to CVAOA is clinically insignificant, because the amount of CVAA conversion to CVAOA is dependent upon residence time in the body. Once excreted into the urine, conversion of CVAA to CVAOA is dependent upon temperature and oxidative potential of the urine. The method also allowed for qualitative analysis for bis(2-chlorovinyl)arsinic Acid (BCVAOA) and (1-chlorovinyl)Arsonic Acid (gem-CVAOA), minor Lewisite metabolites. Traditional methods have ignored these minor metabolites; the bis-metabolites can comprise ∼30% of total Lewisite metabolites from chemical munitions and must be accounted for in the exposure measurement. The ion-pairing chromatography method results in a 5.73 min injection-to-injection cycle time with adequate retention (k′ = 2.9) of CVAOA. The weighted (1/x2) linear least squares regression results have correlation coefficients (r2 > 0.998) for the clinically relevant calibration range of 50–3500 μg L−1. The selectivity of the method is measured by chromatographic resolution from other common arsenic compounds that may interfere with the analysis. The 96-well plate preparation of 0.1 mL sample of human urine results in a method detection limit of 2.2 μg L−1. Quantitative results from proficiency testing specimens demonstrate the accuracy (−7.1 to +4.3%) of the method. Quality control data demonstrate inter-analyst precise (3.1 to 3.3%) quantitative results of the method. An accelerated Arrhenius matrix-matched stability study demonstrates Lewisite metabolites are stabile in urine far greater than a year. The trivalent arsenic, CVAA oxidation half-life is estimated at normal body temperature in vitro at 6.2 days. The combined sample preparation and analysis portions of this emergency response method have a throughput of 250 samples per day.
Dianne F Jolley - One of the best experts on this subject based on the ideXlab platform.
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toxicity biotransformation and mode of action of arsenic in two freshwater microalgae chlorella sp and monoraphidium arcuatum
Environmental Toxicology and Chemistry, 2005Co-Authors: Jacqueline L Levy, Merrin S Adams, William A Maher, Jason K. Kirby, Jennifer L Stauber, Dianne F JolleyAbstract:The toxicity of As(V) and As(III) to two axenic tropical freshwater microalgae, Chiarella sp. and Monoraphidium urcuatum. was determined using 72-h growth rate-inhibition bioassays. Both organisms were tolerant to As(III) (72-h concentration to cause 50% inhibition of growth rate (IC50). of 25 and 15 mg As(III)/L, respectively). Chiarella sp. also was tolerant to As(V) with no effect on growth rate over 72 h at concentrations up to 0.8 mg/L (72-h IC50 of 25 mg As(V)/L). Monoraphidium arcuatum was more sensitive to As(V) (72-h IC50 of 0.25 mg As(V)/L). An increase in phosphate in the growth medium (0.15-1.5 mg ~-/L) decreased toxicity, i.e., the 72-h IC50 value for M. arcuatum increased from 0.25 mg As(V)/L to 4.5 mg As(V)/L, while extracellular As and intracellular As decreased, indicating competition between arsenate and phosphate for cellular uptake. Both microalgae reduced As(V) to As(III) in the cell, with further biological transformation to methylated species (monomethyl Arsonic Acid and dimethyl arsinic Acid) and phosphate arsenoriboside. Less than 0.01 % of added As(V) was incorporated into algal cells, suggesting that bioaccumulation and subsequent methylation was not the primary mode of detoxification. When exposed to As(V), both species reduced As(V) to As(III); however, only M. arcuatum excreted As(III) into solution. Intracellular arsenic reduction may be coupled to thiol oxidation in both species. Arsenic toxicity most likely was due to arsenite accumulation in the cell, when the ability to excrete and/or methylate arsenite was overwhelmed at high arsenic concentrations. Arsenite may bind to intracellular thiols, such as glutathione, potentially disrupting the ratio of reduced to oxidized glutathione and, consequently, inhibiting cell division. Keywords-Arsenic Algae Toxicity Phosphate Biotransformation
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toxicity biotransformation and mode of action of arsenic in two freshwater microalgae chlorella sp and monoraphidium arcuatum
Environmental Toxicology and Chemistry, 2005Co-Authors: Jacqueline L Levy, Merrin S Adams, William A Maher, Jason K. Kirby, Jennifer L Stauber, Dianne F JolleyAbstract:The toxicity of As(V) and As(III) to two axenic tropical freshwater microalgae, Chlorella sp. and Monoraphidium arcuatum, was determined using 72-h growth rate-inhibition bioassays. Both organisms were tolerant to As(III) (72-h concentration to cause 50% inhibition of growth rate [IC50], of 25 and 15 mg As[III]/L, respectively). Chlorella sp. also was tolerant to As(V) with no effect on growth rate over 72 h at concentrations up to 0.8 mg/L (72-h IC50 of 25 mg As[V]/L). Monoraphidium arcuatum was more sensitive to As(V) (72-h IC50 of 0.25 mg As[V]/L). An increase in phosphate in the growth medium (0.15-1.5 mg PO4(3-)/L) decreased toxicity, i.e., the 72-h IC50 value for M. arcuatum increased from 0.25 mg As(V)/L to 4.5 mg As(V)/L, while extracellular As and intracellular As decreased, indicating competition between arsenate and phosphate for cellular uptake. Both microalgae reduced As(V) to As(III) in the cell, with further biological transformation to methylated species (monomethyl Arsonic Acid and dimethyl arsinic Acid) and phosphate arsenoriboside. Less than 0.01% of added As(V) was incorporated into algal cells, suggesting that bioaccumulation and subsequent methylation was not the primary mode of detoxification. When exposed to As(V), both species reduced As(V) to As(III); however, only M. arcuatum excreted As(III) into solution. Intracellular arsenic reduction may be coupled to thiol oxidation in both species. Arsenic toxicity most likely was due to arsenite accumulation in the cell, when the ability to excrete and/or methylate arsenite was overwhelmed at high arsenic concentrations. Arsenite may bind to intracellular thiols, such as glutathione, potentially disrupting the ratio of reduced to oxidized glutathione and, consequently, inhibiting cell division.