The Experts below are selected from a list of 5550 Experts worldwide ranked by ideXlab platform
E Mader - One of the best experts on this subject based on the ideXlab platform.
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effects of Fibre Coating size on properties of glass Fibre vinyl ester composites
Composites Part A-applied Science and Manufacturing, 1999Co-Authors: Anders Sjogren, Roberts Joffe, Lars Berglund, E MaderAbstract:Abstract Effects of Fibre Coating (size) on transverse cracking has been investigated. Two glass Fibre/vinyl ester model composites were studied, denoted CA and NoCA and based on different size compositions. Various single Fibre tests were not able to quantify the interfacial failure of CA as the interface never failed. The CA size consisted of a film former and a methacrylsilane-coupling agent whereas the NoCA size did not contain any coupling agent. The study reveals limitations with single Fibre composite tests for Fibre/matrix combinations with high interfacial toughness. Cross-ply laminates based on NoCA demonstrated significant inferior transverse cracking toughness as compared with CA laminates. Composites based on commercially sized glass Fibre were also investigated and they performed almost as poorly as the NoCA material, demonstrating large potential for improvement in commercial composites. Results further indicate that the remarkable transverse cracking toughness of the CA material stems partly from strong Fibre/matrix adhesion but also from high ductility of the matrix region close to the Fibre surface.
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Effects of Fibre Coating (size) on properties of glass Fibre/vinyl ester composites
Composites Part A-applied Science and Manufacturing, 1999Co-Authors: Anders Sjogren, Roberts Joffe, Lars Berglund, E MaderAbstract:Abstract Effects of Fibre Coating (size) on transverse cracking has been investigated. Two glass Fibre/vinyl ester model composites were studied, denoted CA and NoCA and based on different size compositions. Various single Fibre tests were not able to quantify the interfacial failure of CA as the interface never failed. The CA size consisted of a film former and a methacrylsilane-coupling agent whereas the NoCA size did not contain any coupling agent. The study reveals limitations with single Fibre composite tests for Fibre/matrix combinations with high interfacial toughness. Cross-ply laminates based on NoCA demonstrated significant inferior transverse cracking toughness as compared with CA laminates. Composites based on commercially sized glass Fibre were also investigated and they performed almost as poorly as the NoCA material, demonstrating large potential for improvement in commercial composites. Results further indicate that the remarkable transverse cracking toughness of the CA material stems partly from strong Fibre/matrix adhesion but also from high ductility of the matrix region close to the Fibre surface.
Florence Pannie - One of the best experts on this subject based on the ideXlab platform.
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quantitative analysis of volatile selenium metabolites in normal urine by headspace solid phase microextraction gas chromatography inductively coupled plasma mass spectrometry
Talanta, 2009Co-Authors: Maite Ueno, Florence PannieAbstract:Abstract The combination of headspace–solid phase microextraction (HS–SPME) and gas chromatography–inductively coupled plasma mass spectrometry (GC–ICPMS) was evaluated for the determination of volatile selenium metabolites in normal urine samples, i.e. without selenium supplementation. HS–SPME operating conditions were optimised and a sampling time of 10 min was found to be suitable for simultaneous extraction of dimethylselenide (DMSe) and dimethyldiselenide (DMDSe). The amount of DMSe and DMDSe extracted onto Fibre Coating was calculated in clean matrix, i.e. Milli-Q water, on the basis of depletion experiments. When applied to normal urine samples, the developed method allowed the detection of four volatile selenium containing species, among which DMSe and DMDSe could be quantified by standard additions.
Florence Pannier - One of the best experts on this subject based on the ideXlab platform.
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Quantitative analysis of volatile selenium metabolites in normal urine by headspace solid phase microextraction gas chromatography-inductively coupled plasma mass spectrometry
Talanta, 2009Co-Authors: M. Bueno, Florence PannierAbstract:The combination of headspace-solid phase microextraction (HS-SPME) and gas chromatography-inductively coupled plasma mass spectrometry (GC-ICPMS) was evaluated for the determination of volatile selenium metabolites in normal urine samples, i.e. without selenium supplementation. HS-SPME operating conditions were optimised and a sampling time of 10 min was found to be suitable for simultaneous extraction of dimethylselenide (DMSe) and dimethyldiselenide (DMDSe). The amount of DMSe and DMDSe extracted onto Fibre Coating was calculated in clean matrix, i.e. Milli-Q water, on the basis of depletion experiments. When applied to normal urine samples, the developed method allowed the detection of four volatile selenium containing species, among which DMSe and DMDSe could be quantified by standard additions. © 2008 Elsevier B.V. All rights reserved.
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.
Jorgen Ogaard Madse - One of the best experts on this subject based on the ideXlab platform.
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application of head space solid phase microextraction for the analysis of volatile metabolites emitted by penicillium species
Journal of Microbiological Methods, 1996Co-Authors: Torbe Nilsso, Thomas Ostenfeld Larse, Luca Montanarella, Jorgen Ogaard MadseAbstract:Head-space solid-phase microextraction (HS-SPME) has been used to collect volatile organic compounds (VOCs) emitted from fungi of the genus Penicillium. Gas chromatography combined with mass spectrometry (GC-MS) was employed for the analysis of the profiles of volatile metabolites characteristic for each species. The results obtained by HS-SPME compared favourably with those obtained by Tenax adsorption. The following characteristic metabolites were detected: isopentyl alcohol, 1-octene-3-ol, 3-octanone, 3-octanol, 2-methylisoborneol and geosmin, together with the not previously reported acetates of 1-octene-3-ol and 3-octanol. Further, several mono- and sesquiterpene hydrocarbons and alcohols were identified, many of those for the first time from Penicillium species. The growth conditions were found to be of major importance for the quantitative aspects. Distribution coefficients between the Fibre Coating and air were determined for some typical fungal metabolites using polyacrylate and polydimethylsiloxane as Fibre Coatings. No significant differences in the results for the two Fibre Coatings were observed for non-polar to slightly polar compounds, whereas the more polar compounds were better extracted by the polyacrylate Fibre Coating. However, the equilibration times are longer with this Fibre Coating. Increasing responses were observed with decreasing volatility of the compounds for both types of Fibre Coating. Being a rapid, simple and practically non-interfering technique, HS-SPME has a great potential use in the analysis of biogenic VOC emissions, including chemotaxonomical studies.