The Experts below are selected from a list of 165 Experts worldwide ranked by ideXlab platform
James H. Weber - One of the best experts on this subject based on the ideXlab platform.
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Optimization of method for speciation of mercury(II), monomethylmercury cation, Dimethylmercury and diethylmercury by hydride generation
Applied Organometallic Chemistry, 1994Co-Authors: James H. Weber, Richard PukAbstract:This paper describes optimization details of an analytical method development of a hydride-generation procedure for speciation of mercury(II), monomethylmercury cation, Dimethylmercury, and diethylmercury using a heated quartz furnace with an atomic absorption spectrophotometer (AAS) as a detector. Typically a new analytical method is developed in steps such as the following: (1) determining analytes individually to confirm retention times and the lack of decomposition during the procedure; (2) comparing peak areas of all analytes as a function of quartz furnace temperature to optimize atomization for AAS detection; (3) conducting factorial experiments to determine which hydride-generation reaction conditions are important in maximizing peak areas and which conditions interact with each other; (4) using the simplex optimization method to give final optimization of reaction conditions. These steps result in conditions that maximize optimized peak areas for analytes while minimizing experimental error.
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Determination of mercury(II), monomethylmercury cation, Dimethylmercury and diethylmercury by hydride generation, cryogenic trapping and atomic absorption spectrometric detection
Analytica Chimica Acta, 1994Co-Authors: Richard Puk, James H. WeberAbstract:Abstract Mercury(II), monomethylmercury cation (MeHg), Dimethylmercury (Me 2 Hg) and diethylmercury (Et 2 Hg) were simultaneously determined from aqueous samples by hydride generation volatilization, trapping and separation on a chromatographic column, and detection by atomic absorption spectrophotometry in a heated quartz furnace. Simplex optimization showed us the most effective choice of hydride formation and purge conditions. Absolute detection limits are 50 pg for the three organomercury compounds and 110 pg for Hg(II). Calibration curves are linear from 0.05 to 5 ng, and the reproducibility range for 1 Hg of the four analytes is 3–7%. Large differences among measured MeHg concentrations in a recent interlaboratory study using different measurement methods confirm that a new, completely independent method for determining mercury compounds in environmental samples is important. The method was applied to estuarine samples of the marsh grass Spartina alterniflora and eelgrass ( Zostera marina L.) and found Hg(II), MeHg (eelgrass only) and Me 2 Hg. Our difficulties in determining Me 2 Hg suggest that it is more common in the aquatic environment than commonly believed.
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Critical review of analytical methods for determination of inorganic mercury and methylmercury compounds
Applied Organometallic Chemistry, 1994Co-Authors: Richard Puk, James H. WeberAbstract:This review describes determinations of mercury compounds under three categories: total mercury; separate determinations of inorganic mercury(II) and organomercury compounds by selective reduction; and speciation of inorganic mercury(II), monomethylmercury cation, and Dimethylmercury. Topics described for each category include sample treatment, separation, detection, and limit of detection. Finally, we note that most methods would not detect Dimethylmercury if it were present.
Richard Puk - One of the best experts on this subject based on the ideXlab platform.
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Optimization of method for speciation of mercury(II), monomethylmercury cation, Dimethylmercury and diethylmercury by hydride generation
Applied Organometallic Chemistry, 1994Co-Authors: James H. Weber, Richard PukAbstract:This paper describes optimization details of an analytical method development of a hydride-generation procedure for speciation of mercury(II), monomethylmercury cation, Dimethylmercury, and diethylmercury using a heated quartz furnace with an atomic absorption spectrophotometer (AAS) as a detector. Typically a new analytical method is developed in steps such as the following: (1) determining analytes individually to confirm retention times and the lack of decomposition during the procedure; (2) comparing peak areas of all analytes as a function of quartz furnace temperature to optimize atomization for AAS detection; (3) conducting factorial experiments to determine which hydride-generation reaction conditions are important in maximizing peak areas and which conditions interact with each other; (4) using the simplex optimization method to give final optimization of reaction conditions. These steps result in conditions that maximize optimized peak areas for analytes while minimizing experimental error.
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Determination of mercury(II), monomethylmercury cation, Dimethylmercury and diethylmercury by hydride generation, cryogenic trapping and atomic absorption spectrometric detection
Analytica Chimica Acta, 1994Co-Authors: Richard Puk, James H. WeberAbstract:Abstract Mercury(II), monomethylmercury cation (MeHg), Dimethylmercury (Me 2 Hg) and diethylmercury (Et 2 Hg) were simultaneously determined from aqueous samples by hydride generation volatilization, trapping and separation on a chromatographic column, and detection by atomic absorption spectrophotometry in a heated quartz furnace. Simplex optimization showed us the most effective choice of hydride formation and purge conditions. Absolute detection limits are 50 pg for the three organomercury compounds and 110 pg for Hg(II). Calibration curves are linear from 0.05 to 5 ng, and the reproducibility range for 1 Hg of the four analytes is 3–7%. Large differences among measured MeHg concentrations in a recent interlaboratory study using different measurement methods confirm that a new, completely independent method for determining mercury compounds in environmental samples is important. The method was applied to estuarine samples of the marsh grass Spartina alterniflora and eelgrass ( Zostera marina L.) and found Hg(II), MeHg (eelgrass only) and Me 2 Hg. Our difficulties in determining Me 2 Hg suggest that it is more common in the aquatic environment than commonly believed.
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Critical review of analytical methods for determination of inorganic mercury and methylmercury compounds
Applied Organometallic Chemistry, 1994Co-Authors: Richard Puk, James H. WeberAbstract:This review describes determinations of mercury compounds under three categories: total mercury; separate determinations of inorganic mercury(II) and organomercury compounds by selective reduction; and speciation of inorganic mercury(II), monomethylmercury cation, and Dimethylmercury. Topics described for each category include sample treatment, separation, detection, and limit of detection. Finally, we note that most methods would not detect Dimethylmercury if it were present.
Donald A. Drum - One of the best experts on this subject based on the ideXlab platform.
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Are toxic biometals destroying your children’s future?
BioMetals, 2009Co-Authors: Donald A. DrumAbstract:Cadmium, arsenic, lead, and mercury have been linked to autism, attention deficit disorder, mental retardation and death of children. Mercury in thimerosal found in many vaccines and flu shots contributes significantly to these problems. Decomposition of the thimerosal can produce more toxic compounds, either methylethylmercury or diethylmercury, in the body. These compounds have a toxicity level similar to Dimethylmercury. Within the human body, a mitochondrial disorder may release the more toxic form of mercury internally. Young children and pregnant women must minimize internal exposure to the vaccines and flu shots containing mercury.
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Are toxic biometals destroying your children's future?
Biometals : an international journal on the role of metal ions in biology biochemistry and medicine, 2009Co-Authors: Donald A. DrumAbstract:Cadmium, arsenic, lead, and mercury have been linked to autism, attention deficit disorder, mental retardation and death of children. Mercury in thimerosal found in many vaccines and flu shots contributes significantly to these problems. Decomposition of the thimerosal can produce more toxic compounds, either methylethylmercury or diethylmercury, in the body. These compounds have a toxicity level similar to Dimethylmercury. Within the human body, a mitochondrial disorder may release the more toxic form of mercury internally. Young children and pregnant women must minimize internal exposure to the vaccines and flu shots containing mercury.
Alfred V. Hirner - One of the best experts on this subject based on the ideXlab platform.
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Research Article Toxicity of Volatile Methylated Species of Bismuth, Arsenic, Tin, and Mercury in Mammalian Cells In Vitro
2013Co-Authors: U. Zimmermann, Albert W. Rettenmeier, Alfred V. HirnerAbstract:Copyright © 2011 E. Dopp et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The biochemical transformation of mercury, tin, arsenic and bismuth through formation of volatile alkylated species performs a fundamental role in determining the environmental processing of these elements. While the toxicity of inorganic forms of most of these compounds are well documented (e.g., arsenic, mercury) and some of them are of relatively low toxicity (e.g., tin, bismuth), the more lipid-soluble organometals can be highly toxic. In the present study we investigated the cyto- and genotoxicity of five volatile metal(loid) compounds: trimethylbismuth, dimethylarsenic iodide, trimethylarsine, tetramethyltin, and Dimethylmercury. As far as we know, this is the first study investigating the toxicity of volatile metal(loid) compounds in vitro. Our results showed that Dimethylmercury was most toxic to all three used cell lines (CHO-9 cells, CaCo, Hep-G2) followed by dimethylarsenic iodide. Tetramethyltin was the least toxic compound; however, the toxicity was also dependend upon the cell type. Human colon cells (CaCo) were most susceptible to the toxicity of the volatile compounds compared to the other cell lines. We conclude from our study that volatile metal(loid) compounds can be toxic to mammalian cells already at very low concentrations but the toxicity depends upon the metal(loid) species and the exposed cell type. 1
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Toxicity of Volatile Methylated Species of Bismuth, Arsenic, Tin, and Mercury in Mammalian Cells In Vitro
Journal of toxicology, 2011Co-Authors: Elke Dopp, U. Von Recklinghausen, Jörg Hippler, Roland A. Diaz-bone, Jessica Richard, U. Zimmermann, Albert W. Rettenmeier, Alfred V. HirnerAbstract:The biochemical transformation of mercury, tin, arsenic and bismuth through formation of volatile alkylated species performs a fundamental role in determining the environmental processing of these elements. While the toxicity of inorganic forms of most of these compounds are well documented (e.g., arsenic, mercury) and some of them are of relatively low toxicity (e.g., tin, bismuth), the more lipid-soluble organometals can be highly toxic. In the present study we investigated the cyto- and genotoxicity of five volatile metal(loid) compounds: trimethylbismuth, dimethylarsenic iodide, trimethylarsine, tetramethyltin, and Dimethylmercury. As far as we know, this is the first study investigating the toxicity of volatile metal(loid) compounds in vitro. Our results showed that Dimethylmercury was most toxic to all three used cell lines (CHO-9 cells, CaCo, Hep-G2) followed by dimethylarsenic iodide. Tetramethyltin was the least toxic compound; however, the toxicity was also dependend upon the cell type. Human colon cells (CaCo) were most susceptible to the toxicity of the volatile compounds compared to the other cell lines. We conclude from our study that volatile metal(loid) compounds can be toxic to mammalian cells already at very low concentrations but the toxicity depends upon the metal(loid) species and the exposed cell type.
Elke Dopp - One of the best experts on this subject based on the ideXlab platform.
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Toxicity of Volatile Methylated Species of Bismuth, Arsenic, Tin, and Mercury in Mammalian Cells In Vitro
Journal of toxicology, 2011Co-Authors: Elke Dopp, U. Von Recklinghausen, Jörg Hippler, Roland A. Diaz-bone, Jessica Richard, U. Zimmermann, Albert W. Rettenmeier, Alfred V. HirnerAbstract:The biochemical transformation of mercury, tin, arsenic and bismuth through formation of volatile alkylated species performs a fundamental role in determining the environmental processing of these elements. While the toxicity of inorganic forms of most of these compounds are well documented (e.g., arsenic, mercury) and some of them are of relatively low toxicity (e.g., tin, bismuth), the more lipid-soluble organometals can be highly toxic. In the present study we investigated the cyto- and genotoxicity of five volatile metal(loid) compounds: trimethylbismuth, dimethylarsenic iodide, trimethylarsine, tetramethyltin, and Dimethylmercury. As far as we know, this is the first study investigating the toxicity of volatile metal(loid) compounds in vitro. Our results showed that Dimethylmercury was most toxic to all three used cell lines (CHO-9 cells, CaCo, Hep-G2) followed by dimethylarsenic iodide. Tetramethyltin was the least toxic compound; however, the toxicity was also dependend upon the cell type. Human colon cells (CaCo) were most susceptible to the toxicity of the volatile compounds compared to the other cell lines. We conclude from our study that volatile metal(loid) compounds can be toxic to mammalian cells already at very low concentrations but the toxicity depends upon the metal(loid) species and the exposed cell type.