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M. Potin-gautier - One of the best experts on this subject based on the ideXlab platform.
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Organotin speciation in French brandies and wines by solid-phase microextraction and gas chromatography--pulsed flame photometric detection.
Journal of Chromatography A, 2008Co-Authors: J. Heroult, M. Bueno, M. Potin-gautier, G. LespesAbstract:Abstract An analytical method devoted to Organotin compounds (OTC) determination in brandy and wine was developed. It is based on solid-phase microextraction (SPME) of ethylated Organotins. The following operating factors were examined: SPME mode/nature of fibre coating, sample volume/dilution, and sampling time. The optimisation work led to dilute the sample in an aqueous buffer (1/11, v/v ratio) in order to satisfactorily decrease the matrix effects due to competitive sorption of non-OTC species onto/into fibre coating. The optimised operating conditions consist of polydimethylsiloxane (PDMS) coated fibre used in headspace mode for 30 min. In wines, the limits of detection (LOD) and quantification (LOQ) ranged from 1 to 40 and 3 to 80 ng(Sn) L −1 respectively, according to the species. The analytical validation was made by evaluating the accuracy of OTC determination in spiked samples with various concentrations over the whole calibration range, i.e. from LOQ to 1000 ng(Sn) L −1 . Recovery was around 80–110% and precision (relative standard deviation, RSD) was between 12% and 25%. Despite the presence of two chromatographic peaks corresponding to sulphur compounds during brandy analysis, the selectivity of the method is adequate. The analysis confirmed the analytical performances and applicability of the method to wine and brandy samples. The obtained results emphasise the contamination of brandy and wine by Organotins, the storage in plastic container seeming to be confirmed as the main OTC source.
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Organotin speciation in French brandies and wines by solid-phase microextraction and gas chromatography-Pulsed flame photometric detection
Journal of Chromatography A, 2008Co-Authors: J. Heroult, M. Bueno, M. Potin-gautier, G. LespesAbstract:An analytical method devoted to Organotin compounds (OTC) determination in brandy and wine was developed. It is based on solid-phase microextraction (SPME) of ethylated Organotins. The following operating factors were examined: SPME mode/nature of fibre coating, sample volume/dilution, and sampling time. The optimisation work led to dilute the sample in an aqueous buffer (1/11, v/v ratio) in order to satisfactorily decrease the matrix effects due to competitive sorption of non-OTC species onto/into fibre coating. The optimised operating conditions consist of polydimethylsiloxane (PDMS) coated fibre used in headspace mode for 30 min. In wines, the limits of detection (LOD) and quantification (LOQ) ranged from 1 to 40 and 3 to 80 ng(Sn) L-1 respectively, according to the species. The analytical validation was made by evaluating the accuracy of OTC determination in spiked samples with various concentrations over the whole calibration range, i.e. from LOQ to 1000 ng(Sn) L-1. Recovery was around 80-110% and precision (relative standard deviation, RSD) was between 12% and 25%. Despite the presence of two chromatographic peaks corresponding to sulphur compounds during brandy analysis, the selectivity of the method is adequate. The analysis confirmed the analytical performances and applicability of the method to wine and brandy samples. The obtained results emphasise the contamination of brandy and wine by Organotins, the storage in plastic container seeming to be confirmed as the main OTC source. © 2007 Elsevier B.V. All rights reserved.
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Organotin speciation in French brandies and wines by solid-phase microextraction and gas chromatography-Pulsed flame photometric detection
Journal of Chromatography A, 2008Co-Authors: J. Heroult, M. Bueno, M. Potin-gautier, G. LespesAbstract:An analytical method devoted to Organotin compounds (OTC) determination in brandy and wine was developed. It is based on solid-phase microextraction (SPME) of ethylated Organotins. The following operating factors were examined: SPME mode/nature of fibre coating, sample volume/dilution, and sampling time. The optimisation work led to dilute the sample in an aqueous buffer (1/11, v/v ratio) in order to satisfactorily decrease the matrix effects due to competitive sorption of non-OTC species onto/into fibre coating. The optimised operating conditions consist of polydimethylsiloxane (PDMS) coated fibre used in headspace mode for 30 min. In wines, the limits of detection (LOD) and quantification (LOQ) ranged from 1 to 40 and 3 to 80 ng(Sn) L-1 respectively, according to the species. The analytical validation was made by evaluating the accuracy of OTC determination in spiked samples with various concentrations over the whole calibration range, i.e. from LOQ to 1000 ng(Sn) L-1. Recovery was around 80-110% and precision (relative standard deviation, RSD) was between 12% and 25%. Despite the presence of two chromatographic peaks corresponding to sulphur compounds during brandy analysis, the selectivity of the method is adequate. The analysis confirmed the analytical performances and applicability of the method to wine and brandy samples. The obtained results emphasise the contamination of brandy and wine by Organotins, the storage in plastic container seeming to be confirmed as the main OTC source. © 2007 Elsevier B.V. All rights reserved.
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Organotin speciation in Bizerte lagoon (Tunisia)
Science of the Total Environment, 2005Co-Authors: N. Mzoughi, G. Lespes, M. Bravo, M. Dachraoui, M. Potin-gautierAbstract:For the first time, Organotins have been assessed in samples collected from Bizerte lagoon, in Tunisia, during two seasons (summer and winter). The Organotin distribution was studied in marine sediments and mussels tissues of this lagoon. Butyl-, phenyl- and octyltins were determined using a rapid speciation analytical method based on one-step ethylation/extraction with sodium tetraethylborate in aqueous phase. Simultaneously to the ethylation, the extraction was performed by either liquid/liquid extraction (LLE) or head-space solid phase microextraction (HS-SPME). Gas chromatography with pulsed flame photometric detection (GC-PFPD) was used to perform quantitative determination. The technique has been validated using biological and sediment reference materials. The different samples from Bizerte lagoon were found to be moderately contaminated, especially by butyltins. This pollution was attributed to industrial activities, which are very important in this area. Organotins appeared accumulated in both sediments and mussels, while significant degradations of triOrganotins to monosubstituted ones was observed in water. © 2005 Elsevier B.V. All rights reserved.
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Organotin survey in the Adour-Garonne basin.
Water research, 2004Co-Authors: Ch. Bancon-montigny, Gaëtane Lespes, M. Potin-gautierAbstract:Abstract Organotin monitoring was performed in waters of 11 rivers of the southwest of France during a 9 months period, between February and October 2001. Surface sediments were studied during the summer. Eighteen sampling points were chosen as representative of specific industrial or agricultural activities. In most samples, Organotins were detected and butyltins are the most frequently present, with concentrations ranging over 0.2–30 ng(Sn)/L. Phenyltins were detected especially in spring and at the end of summer, which corresponds to likely diffusion from agricultural sources. Some high butyl- and phenyltin concentrations up to 700 ng(Sn)/L occurred during the spring where pesticides for agricultural activities were largely used. Octyltins were present in water frequently as well, with lower concentrations, probably originating from continuous leaching of plastics. Sediments appeared contaminated by the same species, with higher monobutyltin concentrations of about 30–40 μg(Sn)/kg which shows the importance of biological degradations occurring in surface sediments. This non-pesticidal Organotin compounds can also be introduced from leaching of Organotin-stabilized PVC by water. Using the different Organotin concentrations obtained and other physico-chemical parameters measured, such as temperature or water flow rate, a statistical study was performed by principal component analysis. The results obtained allow the main sources of Organotin diffusion to be identified and the hydrological cycle of these compounds better understand.
G. Lespes - One of the best experts on this subject based on the ideXlab platform.
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Organotin speciation in French brandies and wines by solid-phase microextraction and gas chromatography--pulsed flame photometric detection.
Journal of Chromatography A, 2008Co-Authors: J. Heroult, M. Bueno, M. Potin-gautier, G. LespesAbstract:Abstract An analytical method devoted to Organotin compounds (OTC) determination in brandy and wine was developed. It is based on solid-phase microextraction (SPME) of ethylated Organotins. The following operating factors were examined: SPME mode/nature of fibre coating, sample volume/dilution, and sampling time. The optimisation work led to dilute the sample in an aqueous buffer (1/11, v/v ratio) in order to satisfactorily decrease the matrix effects due to competitive sorption of non-OTC species onto/into fibre coating. The optimised operating conditions consist of polydimethylsiloxane (PDMS) coated fibre used in headspace mode for 30 min. In wines, the limits of detection (LOD) and quantification (LOQ) ranged from 1 to 40 and 3 to 80 ng(Sn) L −1 respectively, according to the species. The analytical validation was made by evaluating the accuracy of OTC determination in spiked samples with various concentrations over the whole calibration range, i.e. from LOQ to 1000 ng(Sn) L −1 . Recovery was around 80–110% and precision (relative standard deviation, RSD) was between 12% and 25%. Despite the presence of two chromatographic peaks corresponding to sulphur compounds during brandy analysis, the selectivity of the method is adequate. The analysis confirmed the analytical performances and applicability of the method to wine and brandy samples. The obtained results emphasise the contamination of brandy and wine by Organotins, the storage in plastic container seeming to be confirmed as the main OTC source.
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Organotin speciation in French brandies and wines by solid-phase microextraction and gas chromatography-Pulsed flame photometric detection
Journal of Chromatography A, 2008Co-Authors: J. Heroult, M. Bueno, M. Potin-gautier, G. LespesAbstract:An analytical method devoted to Organotin compounds (OTC) determination in brandy and wine was developed. It is based on solid-phase microextraction (SPME) of ethylated Organotins. The following operating factors were examined: SPME mode/nature of fibre coating, sample volume/dilution, and sampling time. The optimisation work led to dilute the sample in an aqueous buffer (1/11, v/v ratio) in order to satisfactorily decrease the matrix effects due to competitive sorption of non-OTC species onto/into fibre coating. The optimised operating conditions consist of polydimethylsiloxane (PDMS) coated fibre used in headspace mode for 30 min. In wines, the limits of detection (LOD) and quantification (LOQ) ranged from 1 to 40 and 3 to 80 ng(Sn) L-1 respectively, according to the species. The analytical validation was made by evaluating the accuracy of OTC determination in spiked samples with various concentrations over the whole calibration range, i.e. from LOQ to 1000 ng(Sn) L-1. Recovery was around 80-110% and precision (relative standard deviation, RSD) was between 12% and 25%. Despite the presence of two chromatographic peaks corresponding to sulphur compounds during brandy analysis, the selectivity of the method is adequate. The analysis confirmed the analytical performances and applicability of the method to wine and brandy samples. The obtained results emphasise the contamination of brandy and wine by Organotins, the storage in plastic container seeming to be confirmed as the main OTC source. © 2007 Elsevier B.V. All rights reserved.
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Organotin speciation in French brandies and wines by solid-phase microextraction and gas chromatography-Pulsed flame photometric detection
Journal of Chromatography A, 2008Co-Authors: J. Heroult, M. Bueno, M. Potin-gautier, G. LespesAbstract:An analytical method devoted to Organotin compounds (OTC) determination in brandy and wine was developed. It is based on solid-phase microextraction (SPME) of ethylated Organotins. The following operating factors were examined: SPME mode/nature of fibre coating, sample volume/dilution, and sampling time. The optimisation work led to dilute the sample in an aqueous buffer (1/11, v/v ratio) in order to satisfactorily decrease the matrix effects due to competitive sorption of non-OTC species onto/into fibre coating. The optimised operating conditions consist of polydimethylsiloxane (PDMS) coated fibre used in headspace mode for 30 min. In wines, the limits of detection (LOD) and quantification (LOQ) ranged from 1 to 40 and 3 to 80 ng(Sn) L-1 respectively, according to the species. The analytical validation was made by evaluating the accuracy of OTC determination in spiked samples with various concentrations over the whole calibration range, i.e. from LOQ to 1000 ng(Sn) L-1. Recovery was around 80-110% and precision (relative standard deviation, RSD) was between 12% and 25%. Despite the presence of two chromatographic peaks corresponding to sulphur compounds during brandy analysis, the selectivity of the method is adequate. The analysis confirmed the analytical performances and applicability of the method to wine and brandy samples. The obtained results emphasise the contamination of brandy and wine by Organotins, the storage in plastic container seeming to be confirmed as the main OTC source. © 2007 Elsevier B.V. All rights reserved.
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Kinetic degradation processes of butyl- and phenyltins in soils
Chemosphere, 2008Co-Authors: J. Heroult, M. Bueno, Y. Nia, L. Denaix, G. LespesAbstract:The degradation of Organotin compounds (OTC) in agricultural and forest soils is studied in sandy soil samples. Individual experiments involving the three butyl- and the three phenyltins were carried out during 90 d in controlled conditions (darkness, 28 °C, aerobic conditions, 13% moisture) and with spiking concentration representative of environmental levels (20-50 μg(Sn) kg-1). After the validation of first-order degradation kinetic model, mechanisms involved throughout the study were considered. Degradation pathways are proposed for butyl- and phenyltins and discussed according to literature data. The degradation of mono- (MBT, MPhT), di-Organotins (DBT, DPhT) and TBT is clearly identified as a single successive loss of an organic group whereas TPhT is directly degraded to MPhT. The half-life times were dependent on their substitution degree, ranging from 24 (TPhT) to 220 (MBT) d. The less substituted the OTC is, the more persistent it is. In the range 4.3-5.7, pH does not seem to influence OTC degradation under the present operating conditions. Finally this study shows the significant persistence in soil samples in our experimental conditions for most of studied Organotins and highlights the potential impact on soil quality. © 2008 Elsevier Ltd. All rights reserved.
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Organotin speciation in Bizerte lagoon (Tunisia)
Science of the Total Environment, 2005Co-Authors: N. Mzoughi, G. Lespes, M. Bravo, M. Dachraoui, M. Potin-gautierAbstract:For the first time, Organotins have been assessed in samples collected from Bizerte lagoon, in Tunisia, during two seasons (summer and winter). The Organotin distribution was studied in marine sediments and mussels tissues of this lagoon. Butyl-, phenyl- and octyltins were determined using a rapid speciation analytical method based on one-step ethylation/extraction with sodium tetraethylborate in aqueous phase. Simultaneously to the ethylation, the extraction was performed by either liquid/liquid extraction (LLE) or head-space solid phase microextraction (HS-SPME). Gas chromatography with pulsed flame photometric detection (GC-PFPD) was used to perform quantitative determination. The technique has been validated using biological and sediment reference materials. The different samples from Bizerte lagoon were found to be moderately contaminated, especially by butyltins. This pollution was attributed to industrial activities, which are very important in this area. Organotins appeared accumulated in both sediments and mussels, while significant degradations of triOrganotins to monosubstituted ones was observed in water. © 2005 Elsevier B.V. All rights reserved.
Karl Fent - One of the best experts on this subject based on the ideXlab platform.
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Organotin compounds in municipal wastewater and sewage sludge contamination fate in treatment process and ecotoxicological consequences
Science of The Total Environment, 1996Co-Authors: Karl FentAbstract:Abstract Organotin compounds find various applications in industry and agriculture, which may lead to contamination of municipal wastewater and sewage sludge. Here, an overview on the contamination of these media is given, and the behavior of Organotins in the treatment process is described. In raw municipal wastewater of the city of Zurich, Switzerland, mono- (MBT), di- (DBT) and tributyltin (TBT) were detected in the range of 140–560, 130–1030, and 60–220 ng/l, respectively. These compounds were primarily associated with suspended particulates, and transferred from wastewater to the sludge in the primary clarifier of the treatment plant. Both aerobic and anaerobic degradation were found to be insignificant. This has also been shown by a laboratory-scale sludge treatment system. After secondary and tertiary treatment, Organotin concentrations were in the range of
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Organotins in Municipal Wastewater and Sewage Sludge
Organotin, 1996Co-Authors: Karl FentAbstract:Direct entry of tributyltin (TBT) into the aquatic environment is primarily due to its use in antifouling paints on boats, which gives rise to contamination of waters and sediments of marinas, lakes, and coastal areas. To date, there is a lack of knowledge on other Organotin sources and on the contamination of other environmental compartments. Inputs from wastewater and sewage sludge as well as from landfills are not well known. As the consumption of TBT and other Organotins increases, these compounds are of growing importance in wastewater and sewage sludge. This chapter reviews speciation and contamination of wastewater and sludge, and describes the fate of Organotins in a treatment plant. Organotins were determined by capillary gas chromatography with flame photometric detection after extraction and derivatization. In untreated wastewater of the city of Zurich, Switzerland, substantial concentrations of butyltins were determined. Phenyltins, dioctyltin, and tricyclohexyltin were not detected. Average values on six sampling days were 245 ng l-1 monobutyltin (MBT), 523 ng l-1 dibutyltin (DBT), and 157 ng l-1 TBT. The mean daily load of Organotin was 122 g. Partitioning in wastewater showed that ~90% of the butyltins was associated with suspended solids in the influent, and then the percentage dropped at each successive stage of the treatment process. As a consequence, these compounds are removed from raw wastewater by sedimentation in the primary clarifier. Aerobic digestion did not lead to a significant elimination from wastewater, and anaerobic digestion was not very effective in reducing Organotins in sludge; hence, substantial Organotin levels were determined in digested sludge. Average concentrations were 0.78 mg kg-1 MBT, 0.98 mg kg-1 DBT, and 0.99 mg kg-1 TBT (dry weight). Organotins are therefore efficiently removed from wastewater (elimination 90%), but they become enriched in sewage sludge (daily load 59 g d-1). Sludge is disposed of in landfills and at sea and is used in agriculture as a soil amendment to a large extent, giving a transfer path into the aquatic and terrestrial environment unrecognized thus far. Mono-, di-, and tributyltin residues have also been determined in the leachate of a landfill where the total butyltin concentration was 373 ng l-1. The environmental input from landfills, however, is not as important as that from untreated wastewater and sewage sludge.
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Ecotoxicology of Organotin compounds.
Critical reviews in toxicology, 1996Co-Authors: Karl FentAbstract:Organotin compounds are ubiquitous contaminants in the environment. The high biological activity of some compounds toward aquatic organisms lead to deleterious impacts in aquatic ecosystems. Here, the aquatic ecotoxicology of Organotins is reviewed based on a multidisciplinary approach involving environmental chemical, toxicological, and ecological aspects. Basic results were obtained both with field and laboratory studies, and some of the most important recent results and conclusions are critically reviewed. The contamination of and fate in aquatic systems is reported and linked with effects at different levels of biological organization. Major emphasis is placed on the development of a concept of ecotoxicology that encompasses not only effect assessment alone, but also integrates environmental chemistry with aquatic toxicology. Thereby, the influence of speciation for bioavailability, basic modes of toxic action, and aquatic toxicity are discussed. This case study on Organotins allows to a certain extent generalizations to ecotoxicology in general.
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occurrence of Organotins in municipal wastewater and sewage sludge and behavior in a treatment plant
Environmental Science & Technology, 1991Co-Authors: Karl Fent, Markus D MuellerAbstract:THe behavior of selected Organotin species in a wastewater treatment plant of Zurich, Switzerland, was studied. In untreated wastewater, monobutyltin (MBT), dibutyltin (DBT), and tributyltin (TBT) were detected in the range of 136-564, 127-1,026, and 64-217 ng/L, respectively, of which 81-92% were associated with suspended solids. During treatment, the fraction of Organotins in the particulate phase decreased with decreasing suspended solids concentration. All Organotin species monitored were found to be efficiently removed from wastewater, mainly by sedimentation in the primary clarifier. In the secondary effluent, levels of different Organotins were in the range of 7-47 ng/L. These compounds were transferred into sewage sludge, indicating that the most important process for the elimination of Organotins was adsorption into sludge. Residues of MBT, DBT, and TBT in digested sludges were in the range of 0.10-0.97, 0.41-1.24, and 0.28-1.51 mg/kg (dry weight), respectively.
William Bourguet - One of the best experts on this subject based on the ideXlab platform.
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Activation of RXR-PPAR heterodimers by Organotin environmental endocrine disruptors.
EMBO Reports, 2009Co-Authors: Albane Le Maire, Marina Grimaldi, Dominique Roecklin, Sonia Dagnino, Valérie Vivat-hannah, Patrick Balaguer, William BourguetAbstract:The nuclear receptor retinoid X receptor-alpha (RXR-alpha)-peroxisome proliferator-activated receptor-gamma (PPAR-gamma) heterodimer was recently reported to have a crucial function in mediating the deleterious effects of Organotin compounds, which are ubiquitous environmental contaminants. However, because Organotins are unrelated to known RXR-alpha and PPAR-gamma ligands, the mechanism by which these compounds bind to and activate the RXR-alpha-PPAR-gamma heterodimer at nanomolar concentrations has remained elusive. Here, we show that tributyltin (TBT) activates all three RXR-PPAR-alpha, -gamma, -delta heterodimers, primarily through its interaction with RXR. In addition, the 1.9 A resolution structure of the RXR-alpha ligand-binding domain in complex with TBT shows a covalent bond between the tin atom and residue Cys 432 of helix H11. This interaction largely accounts for the high binding affinity of TBT, which only partly occupies the RXR-alpha ligand-binding pocket. Our data allow an understanding of the binding and activation properties of the various Organotins and suggest a mechanism by which these tin compounds could affect other nuclear receptor signalling pathways.
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activation of rxr ppar heterodimers by Organotin environmental endocrine disruptors
EMBO Reports, 2009Co-Authors: Marina Grimaldi, Dominique Roecklin, Sonia Dagnino, Patrick Balaguer, William Bourguet, Albane Le Maire, Valerie VivathannahAbstract:The nuclear receptor retinoid X receptor-α (RXR-α)–peroxisome proliferator-activated receptor-γ (PPAR-γ) heterodimer was recently reported to have a crucial function in mediating the deleterious effects of Organotin compounds, which are ubiquitous environmental contaminants. However, because Organotins are unrelated to known RXR-α and PPAR-γ ligands, the mechanism by which these compounds bind to and activate the RXR-α–PPAR-γ heterodimer at nanomolar concentrations has remained elusive. Here, we show that tributyltin (TBT) activates all three RXR–PPAR-α, -γ, -δ heterodimers, primarily through its interaction with RXR. In addition, the 1.9 A resolution structure of the RXR-α ligand-binding domain in complex with TBT shows a covalent bond between the tin atom and residue Cys 432 of helix H11. This interaction largely accounts for the high binding affinity of TBT, which only partly occupies the RXR-α ligand-binding pocket. Our data allow an understanding of the binding and activation properties of the various Organotins and suggest a mechanism by which these tin compounds could affect other nuclear receptor signalling pathways.
O. F. X. Donard - One of the best experts on this subject based on the ideXlab platform.
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Toxicity of butyltin, phenyltin and inorganic tin compounds to sulfate-reducing bacteria isolated from anoxic marine sediments
Applied Organometallic Chemistry, 2000Co-Authors: J.-f. Lascourrèges, Pierre Caumette, O. F. X. DonardAbstract:The toxicity of butyltin, phenyltin and inorganic tin compounds to three pure strains of sulfate-reducing bacteria (SRB), isolated from a tributyltin (TBT)-polluted sediment, was determined. The isolated strains were identified as belonging to the genus Desulfovibrio. A new toxicological index (GR25) was developed to assay the toxicity of Organotin compounds. Deleterious effects on suspended anaerobic cell cultures were observed for concentrations ranging between 500 and 600 μM for tin tetrachloride, 55 and 260 μM for triOrganotins, 30 and 90 μM for diOrganotins, and 1 and 6 μM for mono-Organotins. Whereas the number of substituents influenced the toxicity of Organotins, the type of substituent (butyl or phenyl) proved to have little or no impact. Trisubstituted compounds (tributyl-and triphenyl-tin) were less toxic to these strains of SRB than the monosubstituted forms (monobutyl- and monophenyl-tin). This is the opposite trend to that currently reported for aerobic organisms. Under the given anoxic conditions, the toxicity of Organotin compounds obtained yielded a significant negative correlation with the total surface area (TSA) of the tested molecules. Comparison of the TBT toxicity data observed for different microbial groups suggests that the tolerance of bacteria to Organotin compounds might be related to Organotin-cell wall interactions as well as to aerobic or anaerobic metabolise pathways.
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Organotin compounds in trimethyltlin-treated rats and in human brain in Alzheimer's Disease
Human and Experimental Toxicology, 1997Co-Authors: F. Martin, O. F. X. Donard, F.m. Corrigan, J. Kelly, J.a.o. Besson, D.f. HorrobinAbstract:As blood tin concentrations are elevated in Alzheimer's disease and as some low molecular weight Organotin compounds are neurotoxic, we have attempted to detect Organotins in brain in Alzheimer's Disease. First we measured the concentration of trimethyltin (TMT) in the brains of rats which had been exposed to memory-impairing concentrations of TMT and, as the method of linking hydride generation, cryogenic trapping, gas chromatographic separation and atomic absorption spectrophotometric detection permitted the measurements of Organotin compounds when the total tin was greater than 0.2 nanograms, we applied these techniques to human brain tissue, some of which showed neuropathological evidence of Alzheimer's Disease. No low molecular weight Organotin compounds were detected in the human brain tissue, but it is possible that tin may be complexed with large organic molecules, the hydrides of which would not be volatile, but which could be identified by liquid chromatography.
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Aqueous ethylation of Organotin compounds in simple solution for speciation analysis by cryofocussing and detection by atomic absorption spectrometry — comparison with hydride generation
Fresenius' Journal of Analytical Chemistry, 1995Co-Authors: F. M. Martin, O. F. X. DonardAbstract:A 2^3 factorial experimental design has been used to determine the optimum reaction conditions for Organotin ethylation in simple aqueous solutions for speciation by Cryogenic Trapping/ Gas Chromatography/Atomic Absorption Spectrometry (CT/GC/AAS). The factors chosen and their levels of variation (− and +) were the pH of the solution (levels 3 and 5), the amount of NaBEt_4 added (levels 1 and 9 mg) to the Organotins and the time of ethylation reaction (levels 10 and 20 min). Optimum conditions were investigated for monomethyltin (MMT), diethyltin (DET) and dibutyltin (DBT) in mixed solution at a concentration of 10 ng of each Sn compound in 50 ml of solution (200 ng·l^−1). The influence of the different factors on the yield of the ethylation reaction in the ranges investigated depends on the degree of substitution and the nature of the alkyl groups of the Organotins. The ethylation reaction for DET and DBT is more efficient at high pH levels, MMT gives higher yields at lower pH. Both MMT and DET require a high amount of reagent, while reagent concentration has no real influence on the DBT signal. Comparison of hydride generation and ethylation as derivatisation procedures for Organotin speciation has been performed in simple solutions. Under these analytical conditions, hydride generation is shown to be slightly more sensitive than ethylation by a factor of 1.4 for MMT and DET and 2 for DBT. However derivatisation using ethylation provides more reproducible results and is not affected by inorganic interferents.
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Aqueous ethylation of Organotin compounds in simple solution for speciation analysis by cryofocussing and detection by atomic absorption spectrometry - comparison with hydride generation
Fresenius' Journal of Analytical Chemistry, 1995Co-Authors: F. M. Martin, O. F. X. DonardAbstract:A 23 factorial experimental design has been used to determine the optimum reaction conditions for Organotin ethylation in simple aqueous solutions for speciation by Cryogenic Trapping/ Gas Chromatography/Atomic Absorption Spectrometry (CT/GC/AAS). The factors chosen and their levels of variation (- and +) were the pH of the solution (levels 3 and 5), the amount of NaBEt4 added (levels 1 and 9 mg) to the Organotins and the time of ethylation reaction (levels 10 and 20 min). Optimum conditions were investigated for monomethyltin (MMT), diethyltin (DET) and dibutyltin (DBT) in mixed solution at a concentration of 10 ng of each Sn compound in 50 ml of solution (200 ng·l-1). The influence of the different factors on the yield of the ethylation reaction in the ranges investigated depends on the degree of substitution and the nature of the alkyl groups of the Organotins. The ethylation reaction for DET and DBT is more efficient at high pH levels, MMT gives higher yields at lower pH. Both MMT and DET require a high amount of reagent, while reagent concentration has no real influence on the DBT signal. Comparison of hydride generation and ethylation as derivatisation procedures for Organotin speciation has been performed in simple solutions. Under these analytical conditions, hydride generation is shown to be slightly more sensitive than ethylation by a factor of 1.4 for MMT and DET and 2 for DBT. However derivatisation using ethylation provides more reproducible results and is not affected by inorganic interferents. © 1995 Springer-Verlag.
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Interference mechanisms and reduction during the speciation of Organotin compounds by hydride generation, cryoseparation and detection by atomic absorption spectrometry
Journal of Analytical Atomic Spectrometry, 1994Co-Authors: F. M. Martin, O. F. X. DonardAbstract:Interferences generated by inorganic elements during the speciation of Organotins and the effect of masking agents have been studied using hydride generation (HG) on-line with cryogenic trapping (CT), gas chromatographic (GC) separation and detection by atomic absorption spectrometry (AAS). This study was performed on a mixture of Organotin species (monomethyltin (MMT), monobutyltin (MBT), dibutyltin (DBT) and tributyltin (TBT) at concentration levels of 5 ng of Sn of each in 50 ml of solution (100 ng I-1). Interfering elements (Al, As, Cd, Co, Cr, Cu, Fe, Ni, Pb, Sb, Se or Zn) (100 μg), investigated individually in solution in the presence of the Organotins, do not lead to the same signal depression for each Organotin compound studied, possibly owing to different interference mechanisms. Interferences generated by inorganic elements can be partitioned between the solution and gaseous phases, showing that interferences may occur both during the solution and the gaseous steps for all Organotins studied. Masking agents (EDTA and L-cysteine) to reduce interferences have been successfully used for Organotin speciation. The presence of ethylenediaminetetraacetic acid (EDTA) in the reaction flask suppresses most of the interferences by forming complexes with the inorganic species and preventing them from reacting and altering the formation of DBT and TBT hydrides. However, EDTA also forms complexes with MMT and MBT. L-Cysteine improves the reproducibility and sensitivity of MBT determination and prevents the interfering effects of inorganic elements on the speciation of Organotins. Interferences mechanisms are discussed.
