The Experts below are selected from a list of 42 Experts worldwide ranked by ideXlab platform
John D. Wells - One of the best experts on this subject based on the ideXlab platform.
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Optimization of silylation using N-methyl-N-(trimethylsilyl)-trifluoroacetamide, N,O-bis-(trimethylsilyl)-trifluoroacetamide and N-(tert-butyldimethylsilyl)-N-methyltrifluoroacetamide for the determination of the estrogens estrone and 17α-ethinylestr
Journal of Chromatography A, 2006Co-Authors: Ali Shareef, Michael J. Angove, John D. WellsAbstract:Abstract This paper reports an improved silylation procedure for simultaneous determination of the steroid hormones 17α-ethinylestradiol (EE2) and estrone (E1) using gas chromatography–mass spectrometry (GC–MS). This follows a re-assessment of some of the popular silylation procedures using N -methyl- N -trimethylsilyltrifluoroacetamide (MSTFA), N - O -bis-(trimethylsilyl)-trifluoroacetamide (BSTFA) and N -( tert -butyldimethylsilyl)- N -methyltrifluoroacetamide (MTBSTFA), which lead to the formation of trimethylsilyl (TMS) and tert -butyldimethylsilyl (TBS) derivatives. Silylation of EE2 using MSTFA or BSTFA + 1% TMCS in ethyl acetate, acetonitrile and dichloromethane solvents produced multiple peaks corresponding to TMS-E1, and 3-mono-TMS-EE2 and/or 3,17-di-TMS-EE2 in variable proportions depending on the solvent used. When pyridine or dimethyl formamide solvents were used in the silylation of EE2 under the same reaction conditions, only 3,17-di-TMS-EE2 derivative was formed. Derivatization using MTBSTFA reagents using ethyl acetate, acetonitrile, dichloromethane, pyridine and dimethyl formamide resulted in almost 100% conversion of mono-TBS-EE2 to the TBS-E1. Therefore, typical methods used in some previous GC–MS determinations of E1 and EE2 in environmental water and/or sediment samples are subject to speculation. However, we can confirm that any of the TMS reagents can be used with either pyridine or dimethyl formamide under suitable reaction conditions.
Tzeunyean Lin - One of the best experts on this subject based on the ideXlab platform.
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determination of residual anabolic steroid in meat by gas chromatography ion trap mass spectrometer
Talanta, 2004Co-Authors: Mingren Fuh, Shuyen Huang, Tzeunyean LinAbstract:Abstract The use of natural and synthetic anabolic steroids in animal fattening has been prohibited in Taiwan and many countries because of their potential toxic effect on public health. This paper describes a newly developed gas chromatography–ion trap–mass spectrometry (GC–IT–MS) method for the quantitative determination of various residual anabolic steroids in meat. Anabolic steroid was derivatized with N -methyl- N -trimethylsilytrifluoroacetamide prior to GC–IT–MS analysis. MS 2 was employed for quantitative measurement. In addition, 2 d -estradiol was used as an internal standard. Quantitative determination was based on the ratio of peak area of steroid derivative to peak area of internal standard derivative. Good linearity of each compound, 0.03–1.0 μg/ml, was determined. Solvent extraction was used to extract residual anabolic compounds in meat samples and a solid phase extraction (SPE) procedure was utilized for sample cleanup and pre-concentration. The limits of detection of anabolic compounds approximately ranged from 0.1 to 0.4 μg/kg. The detection limit was comparable with or better than reported methods and was below the minimum required performance limits (MRPLs) established by the European Community (EC). The application of this newly developed method was demonstrated by analyzing various beef, pork, chicken and several animal internal organ samples from local markets.
Ali Shareef - One of the best experts on this subject based on the ideXlab platform.
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Optimization of silylation using N-methyl-N-(trimethylsilyl)-trifluoroacetamide, N,O-bis-(trimethylsilyl)-trifluoroacetamide and N-(tert-butyldimethylsilyl)-N-methyltrifluoroacetamide for the determination of the estrogens estrone and 17α-ethinylestr
Journal of Chromatography A, 2006Co-Authors: Ali Shareef, Michael J. Angove, John D. WellsAbstract:Abstract This paper reports an improved silylation procedure for simultaneous determination of the steroid hormones 17α-ethinylestradiol (EE2) and estrone (E1) using gas chromatography–mass spectrometry (GC–MS). This follows a re-assessment of some of the popular silylation procedures using N -methyl- N -trimethylsilyltrifluoroacetamide (MSTFA), N - O -bis-(trimethylsilyl)-trifluoroacetamide (BSTFA) and N -( tert -butyldimethylsilyl)- N -methyltrifluoroacetamide (MTBSTFA), which lead to the formation of trimethylsilyl (TMS) and tert -butyldimethylsilyl (TBS) derivatives. Silylation of EE2 using MSTFA or BSTFA + 1% TMCS in ethyl acetate, acetonitrile and dichloromethane solvents produced multiple peaks corresponding to TMS-E1, and 3-mono-TMS-EE2 and/or 3,17-di-TMS-EE2 in variable proportions depending on the solvent used. When pyridine or dimethyl formamide solvents were used in the silylation of EE2 under the same reaction conditions, only 3,17-di-TMS-EE2 derivative was formed. Derivatization using MTBSTFA reagents using ethyl acetate, acetonitrile, dichloromethane, pyridine and dimethyl formamide resulted in almost 100% conversion of mono-TBS-EE2 to the TBS-E1. Therefore, typical methods used in some previous GC–MS determinations of E1 and EE2 in environmental water and/or sediment samples are subject to speculation. However, we can confirm that any of the TMS reagents can be used with either pyridine or dimethyl formamide under suitable reaction conditions.
Mingren Fuh - One of the best experts on this subject based on the ideXlab platform.
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determination of residual anabolic steroid in meat by gas chromatography ion trap mass spectrometer
Talanta, 2004Co-Authors: Mingren Fuh, Shuyen Huang, Tzeunyean LinAbstract:Abstract The use of natural and synthetic anabolic steroids in animal fattening has been prohibited in Taiwan and many countries because of their potential toxic effect on public health. This paper describes a newly developed gas chromatography–ion trap–mass spectrometry (GC–IT–MS) method for the quantitative determination of various residual anabolic steroids in meat. Anabolic steroid was derivatized with N -methyl- N -trimethylsilytrifluoroacetamide prior to GC–IT–MS analysis. MS 2 was employed for quantitative measurement. In addition, 2 d -estradiol was used as an internal standard. Quantitative determination was based on the ratio of peak area of steroid derivative to peak area of internal standard derivative. Good linearity of each compound, 0.03–1.0 μg/ml, was determined. Solvent extraction was used to extract residual anabolic compounds in meat samples and a solid phase extraction (SPE) procedure was utilized for sample cleanup and pre-concentration. The limits of detection of anabolic compounds approximately ranged from 0.1 to 0.4 μg/kg. The detection limit was comparable with or better than reported methods and was below the minimum required performance limits (MRPLs) established by the European Community (EC). The application of this newly developed method was demonstrated by analyzing various beef, pork, chicken and several animal internal organ samples from local markets.
Michael J. Angove - One of the best experts on this subject based on the ideXlab platform.
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Optimization of silylation using N-methyl-N-(trimethylsilyl)-trifluoroacetamide, N,O-bis-(trimethylsilyl)-trifluoroacetamide and N-(tert-butyldimethylsilyl)-N-methyltrifluoroacetamide for the determination of the estrogens estrone and 17α-ethinylestr
Journal of Chromatography A, 2006Co-Authors: Ali Shareef, Michael J. Angove, John D. WellsAbstract:Abstract This paper reports an improved silylation procedure for simultaneous determination of the steroid hormones 17α-ethinylestradiol (EE2) and estrone (E1) using gas chromatography–mass spectrometry (GC–MS). This follows a re-assessment of some of the popular silylation procedures using N -methyl- N -trimethylsilyltrifluoroacetamide (MSTFA), N - O -bis-(trimethylsilyl)-trifluoroacetamide (BSTFA) and N -( tert -butyldimethylsilyl)- N -methyltrifluoroacetamide (MTBSTFA), which lead to the formation of trimethylsilyl (TMS) and tert -butyldimethylsilyl (TBS) derivatives. Silylation of EE2 using MSTFA or BSTFA + 1% TMCS in ethyl acetate, acetonitrile and dichloromethane solvents produced multiple peaks corresponding to TMS-E1, and 3-mono-TMS-EE2 and/or 3,17-di-TMS-EE2 in variable proportions depending on the solvent used. When pyridine or dimethyl formamide solvents were used in the silylation of EE2 under the same reaction conditions, only 3,17-di-TMS-EE2 derivative was formed. Derivatization using MTBSTFA reagents using ethyl acetate, acetonitrile, dichloromethane, pyridine and dimethyl formamide resulted in almost 100% conversion of mono-TBS-EE2 to the TBS-E1. Therefore, typical methods used in some previous GC–MS determinations of E1 and EE2 in environmental water and/or sediment samples are subject to speculation. However, we can confirm that any of the TMS reagents can be used with either pyridine or dimethyl formamide under suitable reaction conditions.
