The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform
Joanne R Bone - One of the best experts on this subject based on the ideXlab platform.
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liquid chromatography Flame Ionisation Detection using a nebuliser spray chamber interface part 2 comparison of functional group responses
Journal of Chromatography A, 2012Co-Authors: Erepamowei Young, Roger M Smith, Barry L Sharp, Joanne R BoneAbstract:The application of a LC-nebuliser/spray chamber interface-Flame Ionisation Detection has been demonstrated for the superheated water liquid chromatography of a wide range of aliphatic and aromatic analytes. The linearity and sensitivity of the response of volatile and involatile analytes have been compared. The response of the detector toward different analytes is similar to that in GC-FID and for volatile analytes was comparable to UV Detection. However, the responses from involatile analytes, such as amino acids and carbohydrates, were poor and often lower than for a refractive index detector.
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liquid chromatography Flame Ionisation Detection using a nebuliser spray chamber interface part 1 design and testing
Journal of Chromatography A, 2012Co-Authors: Erepamowei Young, Roger M Smith, Barry L Sharp, Joanne R BoneAbstract:A nebuliser and spray chamber have been used to link a flow injection analyser to a Flame Ionisation detector, with the potential for the combination to be used as a universal detector for liquid chromatography. The hydrogen and air flows were adjusted to achieve a stable system. The detector responded to both volatile and involatile analytes and to compounds with and without chromophores, including alkanes, alkanols, aromatic amides and acids, phenols, amino-acids and carbohydrates and gave a linear response for many analytes. However, for involatile polar analytes it was necessary to add traces of acid or salt to the carrier stream to obtain a linear response.
D L Hawkes - One of the best experts on this subject based on the ideXlab platform.
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development of a static headspace gas chromatographic procedure for the routine analysis of volatile fatty acids in wastewaters
Journal of Chromatography A, 2002Co-Authors: J A Cruwys, Richard M Dinsdale, Freda R Hawkes, D L HawkesAbstract:Abstract An optimised procedure has been developed for the routine analysis of volatile fatty acids in wastewater matrices, using static headspace gas chromatography with Flame Ionisation Detection. Factors such as sample volume, sample pre-treatment and the time and temperature of sample equilibration have been included in an optimisation model designed to provide maximum detector response for acetic, propionic, iso- and n-butyric and iso- and n-valeric acids in the concentration range 0–1000 mg/l. Optimal headspace conditions were observed when equilibrating at 85 °C for 30 min, using a 2.0 ml sample volume with the addition of 1.0 ml of NaHSO4 (62%, w/v) into standard 22.3 ml vials. 2-Ethylbutyric acid was used as an internal standard. The suitability of ordinary least squares regression and weighted least squares regression models for the purposes of calibration and quantification were investigated. A weighted least squares linear regression model applied to the heteroscedastic data provided lower Detection limits, e.g. 3.7 and 3.3 mg/l for acetic and propionic acids.
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development of a static headspace gas chromatographic procedure for the routine analysis of volatile fatty acids in wastewaters
Journal of Chromatography A, 2002Co-Authors: J A Cruwys, Richard M Dinsdale, Freda R Hawkes, D L HawkesAbstract:An optimised procedure has been developed for the routine analysis of volatile fatty acids in wastewater matrices, using static headspace gas chromatography with Flame Ionisation Detection. Factors such as sample volume, sample pre-treatment and the time and temperature of sample equilibration have been included in an optimisation model designed to provide maximum detector response for acetic, propionic, iso- and n-butyric and iso- and n-valeric acids in the concentration range 0-1000 mg/l. Optimal headspace conditions were observed when equilibrating at 85 degrees C for 30 min, using a 2.0 ml sample volume with the addition of 1.0 ml of NaHSO4 (62%, w/v) into standard 22.3 ml vials. 2-Ethylbutyric acid was used as an internal standard. The suitability of ordinary least squares regression and weighted least squares regression models for the purposes of calibration and quantification were investigated. A weighted least squares linear regression model applied to the heteroscedastic data provided lower Detection limits, e.g. 3.7 and 3.3 mg/l for acetic and propionic acids.
Roger M Smith - One of the best experts on this subject based on the ideXlab platform.
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liquid chromatography Flame Ionisation Detection using a nebuliser spray chamber interface part 2 comparison of functional group responses
Journal of Chromatography A, 2012Co-Authors: Erepamowei Young, Roger M Smith, Barry L Sharp, Joanne R BoneAbstract:The application of a LC-nebuliser/spray chamber interface-Flame Ionisation Detection has been demonstrated for the superheated water liquid chromatography of a wide range of aliphatic and aromatic analytes. The linearity and sensitivity of the response of volatile and involatile analytes have been compared. The response of the detector toward different analytes is similar to that in GC-FID and for volatile analytes was comparable to UV Detection. However, the responses from involatile analytes, such as amino acids and carbohydrates, were poor and often lower than for a refractive index detector.
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liquid chromatography Flame Ionisation Detection using a nebuliser spray chamber interface part 1 design and testing
Journal of Chromatography A, 2012Co-Authors: Erepamowei Young, Roger M Smith, Barry L Sharp, Joanne R BoneAbstract:A nebuliser and spray chamber have been used to link a flow injection analyser to a Flame Ionisation detector, with the potential for the combination to be used as a universal detector for liquid chromatography. The hydrogen and air flows were adjusted to achieve a stable system. The detector responded to both volatile and involatile analytes and to compounds with and without chromophores, including alkanes, alkanols, aromatic amides and acids, phenols, amino-acids and carbohydrates and gave a linear response for many analytes. However, for involatile polar analytes it was necessary to add traces of acid or salt to the carrier stream to obtain a linear response.
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superheated water chromatography a green technology for the future
Journal of Chromatography A, 2008Co-Authors: Roger M SmithAbstract:Abstract Reversed phase liquid chromatography using superheated water as the mobile phase, at temperatures between 100 and 250 °C, offers a number of advantages for the analyst. It is an environmentally clean solvent, reducing solvent usage and disposal costs. It has advantages in Detection, allowing UV spectra to be monitored down to short wavelengths, as well as a compatibility with universal Flame Ionisation Detection and mass spectroscopy. By employing deuterium oxide as the eluent, solvent free NMR spectra can be measured. The development of newer more thermally stable stationary phases, including hybrid phases, have expanded the analytes that can be examined and these now range from alkylbenzenes, phenols, alkyl aryl ketones and a number of pharmaceuticals to carboxylic acids, amino acids, and carbohydrates. Very few compounds have been found to be unstable during the analysis. The separation methods can be directly coupled to superheated water extraction providing a totally solvent free system for sample extraction and analysis.
A A Jekel - One of the best experts on this subject based on the ideXlab platform.
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determination of trichothecenes in beer by capillary gas chromatography with Flame Ionisation Detection
Food Chemistry, 2003Co-Authors: R C Schothorst, A A JekelAbstract:Abstract In 1999 and 2000, high concentrations of deoxynivalenol (DON) were found in wheat and breakfast cereals sold on the Dutch market. Besides wheat other grains can be contaminated with trichothecenes. Using these grains in the brewing process, the produced beer could be contaminated with trichothecenes. A previously developed GC–FID method to determine trichothecenes in wheat was made applicable for the determination of trichothecenes (DON, nivalenol, 3-acetyldeoxynivalenol, fusarenon X, T-2 toxin, HT-2 toxin, diacetoxyscirpenol and neosolaniol) in beer. Surveys were carried out in November 2000 and March 2001 to investigate the presence of trichothecenes in beers marketed in the Netherlands. In only three of the 51 beer samples low quantities of DON were found, ranging from 26 to 41 μg/l. Besides DON, no trichothecenes were found in the beers at levels above the limit of quantification (25 μg/l). All positive samples were from so-called top fermentation beers.
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determination of trichothecenes in wheat by capillary gas chromatography with Flame Ionisation Detection
Food Chemistry, 2001Co-Authors: R C Schothorst, A A JekelAbstract:Trichothecenes are mycotoxins produced by several fungal genera. The Fusarium species, mainly, can contaminate a wide range of cereals used for human and animal consumption. Trichothecenes are associated with various adverse health effects in animals and humans. Deoxynivalenol (DON) and nivalenol (NIV) are the trichothecenes most commonly found worldwide, although 3-acetyldeoxynivalenol, fusarenon X, T-2 toxin, HT-2 toxin, diacetoxyscirpenol (DAS) and neosolaniol are also found. They are included in the present study. For the determination of these trichothecenes in wheat, a method based on capillary gas chromatography (GC) with Flame Ionisation Detection (FID) has been developed and validated. The trichothecenes are extracted from the sample matrix by acetonitrile/water (84/16, v/v). Two different Mycosep® clean-up columns are used to purify the extract. The extract is evaporated to dryness and the trichothecenes are derivatised to trimethylsilyl ethers at room temperature. The residue is dissolved in iso-octane and washed with water. The final extract is analysed for trichothecenes by GC with FID. Quantification is based on the internal standard α-chloralose. The average recoveries for the trichothecenes range from 79% for NIV to 116% for DAS. The limit of quantification is 75 μg/kg for each of the individual trichothecenes. The GC-FID method produced good results in an intercomparison study of trichothecene analysis within the European Union Standards, Measurements and Testing Programme. A survey was carried out in the Netherlands in 1999 to detect the presence of trichothecenes in imported wheat. A temporary tolerance limit of 500 μg/kg is in effect in the Netherlands for DON in cleaned wheat. Seven of the 22 wheat samples exceeded this limit; one exceeded the limit by more than 100%. Thirteen of the 22 wheat samples exceeded a proposed DON tolerance limit of 120 μg/kg for cleaned wheat. Indeed, 12 samples exceeded the limit by more than 100%. Besides DON, no trichothecenes were found in the wheat samples at levels above the limit of quantification.
Erepamowei Young - One of the best experts on this subject based on the ideXlab platform.
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liquid chromatography Flame Ionisation Detection using a nebuliser spray chamber interface part 2 comparison of functional group responses
Journal of Chromatography A, 2012Co-Authors: Erepamowei Young, Roger M Smith, Barry L Sharp, Joanne R BoneAbstract:The application of a LC-nebuliser/spray chamber interface-Flame Ionisation Detection has been demonstrated for the superheated water liquid chromatography of a wide range of aliphatic and aromatic analytes. The linearity and sensitivity of the response of volatile and involatile analytes have been compared. The response of the detector toward different analytes is similar to that in GC-FID and for volatile analytes was comparable to UV Detection. However, the responses from involatile analytes, such as amino acids and carbohydrates, were poor and often lower than for a refractive index detector.
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liquid chromatography Flame Ionisation Detection using a nebuliser spray chamber interface part 1 design and testing
Journal of Chromatography A, 2012Co-Authors: Erepamowei Young, Roger M Smith, Barry L Sharp, Joanne R BoneAbstract:A nebuliser and spray chamber have been used to link a flow injection analyser to a Flame Ionisation detector, with the potential for the combination to be used as a universal detector for liquid chromatography. The hydrogen and air flows were adjusted to achieve a stable system. The detector responded to both volatile and involatile analytes and to compounds with and without chromophores, including alkanes, alkanols, aromatic amides and acids, phenols, amino-acids and carbohydrates and gave a linear response for many analytes. However, for involatile polar analytes it was necessary to add traces of acid or salt to the carrier stream to obtain a linear response.