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Dirk W Lachenmeier - One of the best experts on this subject based on the ideXlab platform.
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headspace solid phase microextraction gas chromatography mass spectrometry determination of the characteristic flavourings menthone Isomenthone neomenthol and menthol in serum samples with and without enzymatic cleavage to validate post offence alcoh
Analytica Chimica Acta, 2009Co-Authors: Katja Schulz, Martin Bertau, Katja Schlenz, Steffen Malt, Jan Dressler, Dirk W LachenmeierAbstract:A rapid HS-SPME–GC–MS (headspace solid-phase microextraction–gas chromatography–mass spectrometry) method has been developed for determination of menthone, Isomenthone, neomenthol and menthol in serum samples with and without enzymatic cleavage. These flavour compounds are characteristic markers for consumption of peppermint liqueurs as well as certain digestif bitters, herbal and bitter liqueurs. This method enabled the detection of the four compounds with a limit of detection (LOD) of 2.1 ng mL −1
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Headspace solid-phase microextraction-gas chromatography-mass spectrometry determination of the characteristic flavourings menthone, Isomenthone, neomenthol and menthol in serum samples with and without enzymatic cleavage to validate post-offence alc
Analytica chimica acta, 2009Co-Authors: Katja Schulz, Martin Bertau, Katja Schlenz, Steffen Malt, Jan Dressler, Dirk W LachenmeierAbstract:A rapid HS-SPME-GC-MS (headspace solid-phase microextraction-gas chromatography-mass spectrometry) method has been developed for determination of menthone, Isomenthone, neomenthol and menthol in serum samples with and without enzymatic cleavage. These flavour compounds are characteristic markers for consumption of peppermint liqueurs as well as certain digestif bitters, herbal and bitter liqueurs. This method enabled the detection of the four compounds with a limit of detection (LOD) of 2.1 ng mL(-1) (menthone and Isomenthone), 2.8 ng mL(-1) (neomenthol) and 4.6 ng mL(-1) (menthol), and a limit of quantification (LOQ) of 3.1 ng mL(-1) (menthone and Isomenthone), 4.2 ng mL(-1) (neomenthol) and 6.8 ng mL(-1) (menthol) in serum samples. The method shows good precision intraday (3.2-3.8%) and interday (5.8-6.9%) and a calibration curve determination coefficient (R(2)) of 0.990-0.996. Experiments were conducted with a volunteer, who consumed peppermint liqueur on three different days under controlled conditions. At defined intervals, blood samples were taken, and the concentration-time profiles for serum menthone, Isomenthone, neomenthol and menthol, as free substances as well as glucuronides, were determined. Both menthol and neomenthol underwent a rapid phase II metabolism, but minor amounts of free substances were also detected. Menthone and Isomenthone were rapidly metabolised and were found in lower concentrations and over a shorter time span than the other analytes. In blood samples taken from 100 drivers who claimed to have consumed peppermint liqueur prior to the blood sampling, menthone, Isomenthone, neomenthol and menthol were detected in the serum as free substances in concentrations between 3.1 and 7.0 ng mL(-1) in eight cases (menthone), 3.1 and 11.3 ng mL(-1) in eight cases (Isomenthone), 5.3 and 57.8 ng mL(-1) in nine cases (neomenthol) and 8.0 and 92.1 ng mL(-1) in nine cases (menthol). The sum values of free and conjugated substances ranged between 4.2 and 127.8 ng mL(-1) in 35 cases for neomenthol and 11.0 and 638.2 ng mL(-1) in 59 cases for menthol. Menthone and Isomenthone were not conjugated. These test results confirmed that the analysis of characteristic beverage aroma compounds, such as menthone, Isomenthone, neomenthol and menthol, can be used for specific verification of post-offence alcohol consumption claims.
Osmar A Ferretti - One of the best experts on this subject based on the ideXlab platform.
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hydrogenation of menthone Isomenthone and pulegone with platinum tin catalysts
Catalysis Letters, 2002Co-Authors: Virginia Vetere, Gerardo Fabian Santori, Albertina G Moglioni, Graciela Moltrasio Y Iglesias, Monica L Casella, Osmar A FerrettiAbstract:The hydrogenation of (-)-menthone, (+)-Isomenthone, and (+)-pulegone over SiO2-supported Pt and Pt-Sn catalysts was studied in this work. The modification with tin was performed by means of the techniques of surface organometallic chemistry on metals. This way of modifying the catalysts allowed stereoisomers of menthol to be obtained in a one-step process. The hydrogenation of these terpenones was favored by the presence of tin in the bimetallic phase.
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Hydrogenation of (-)-menthone, (+)-Isomenthone, and (+)-pulegone with platinum/tin catalysts
Catalysis Letters, 2002Co-Authors: Virginia Vetere, Gerardo Fabian Santori, Albertina G Moglioni, Monica L Casella, Graciela Y. Moltrasio Iglesias, Osmar A FerrettiAbstract:The hydrogenation of (-)-menthone, (+)-Isomenthone, and (+)-pulegone over SiO2-supported Pt and Pt-Sn catalysts was studied in this work. The modification with tin was performed by means of the techniques of surface organometallic chemistry on metals. This way of modifying the catalysts allowed stereoisomers of menthol to be obtained in a one-step process. The hydrogenation of these terpenones was favored by the presence of tin in the bimetallic phase.
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Hydrogenation of (–)-Menthone, (+)-Isomenthone, and (+)-Pulegone with Platinum/Tin Catalysts
Catalysis Letters, 2002Co-Authors: Virginia Vetere, Gerardo Fabian Santori, Albertina G Moglioni, Monica L Casella, Graciela Y. Moltrasio Iglesias, Osmar A FerrettiAbstract:The hydrogenation of (-)-menthone, (+)-Isomenthone, and (+)-pulegone over SiO_2-supported Pt and Pt-Sn catalysts was studied in this work. The modification with tin was performed by means of the techniques of surface organometallic chemistry on metals. This way of modifying the catalysts allowed stereoisomers of menthol to be obtained in a one-step process. The hydrogenation of these terpenones was favored by the presence of tin in the bimetallic phase.
Katja Schulz - One of the best experts on this subject based on the ideXlab platform.
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headspace solid phase microextraction gas chromatography mass spectrometry determination of the characteristic flavourings menthone Isomenthone neomenthol and menthol in serum samples with and without enzymatic cleavage to validate post offence alcoh
Analytica Chimica Acta, 2009Co-Authors: Katja Schulz, Martin Bertau, Katja Schlenz, Steffen Malt, Jan Dressler, Dirk W LachenmeierAbstract:A rapid HS-SPME–GC–MS (headspace solid-phase microextraction–gas chromatography–mass spectrometry) method has been developed for determination of menthone, Isomenthone, neomenthol and menthol in serum samples with and without enzymatic cleavage. These flavour compounds are characteristic markers for consumption of peppermint liqueurs as well as certain digestif bitters, herbal and bitter liqueurs. This method enabled the detection of the four compounds with a limit of detection (LOD) of 2.1 ng mL −1
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Headspace solid-phase microextraction-gas chromatography-mass spectrometry determination of the characteristic flavourings menthone, Isomenthone, neomenthol and menthol in serum samples with and without enzymatic cleavage to validate post-offence alc
Analytica chimica acta, 2009Co-Authors: Katja Schulz, Martin Bertau, Katja Schlenz, Steffen Malt, Jan Dressler, Dirk W LachenmeierAbstract:A rapid HS-SPME-GC-MS (headspace solid-phase microextraction-gas chromatography-mass spectrometry) method has been developed for determination of menthone, Isomenthone, neomenthol and menthol in serum samples with and without enzymatic cleavage. These flavour compounds are characteristic markers for consumption of peppermint liqueurs as well as certain digestif bitters, herbal and bitter liqueurs. This method enabled the detection of the four compounds with a limit of detection (LOD) of 2.1 ng mL(-1) (menthone and Isomenthone), 2.8 ng mL(-1) (neomenthol) and 4.6 ng mL(-1) (menthol), and a limit of quantification (LOQ) of 3.1 ng mL(-1) (menthone and Isomenthone), 4.2 ng mL(-1) (neomenthol) and 6.8 ng mL(-1) (menthol) in serum samples. The method shows good precision intraday (3.2-3.8%) and interday (5.8-6.9%) and a calibration curve determination coefficient (R(2)) of 0.990-0.996. Experiments were conducted with a volunteer, who consumed peppermint liqueur on three different days under controlled conditions. At defined intervals, blood samples were taken, and the concentration-time profiles for serum menthone, Isomenthone, neomenthol and menthol, as free substances as well as glucuronides, were determined. Both menthol and neomenthol underwent a rapid phase II metabolism, but minor amounts of free substances were also detected. Menthone and Isomenthone were rapidly metabolised and were found in lower concentrations and over a shorter time span than the other analytes. In blood samples taken from 100 drivers who claimed to have consumed peppermint liqueur prior to the blood sampling, menthone, Isomenthone, neomenthol and menthol were detected in the serum as free substances in concentrations between 3.1 and 7.0 ng mL(-1) in eight cases (menthone), 3.1 and 11.3 ng mL(-1) in eight cases (Isomenthone), 5.3 and 57.8 ng mL(-1) in nine cases (neomenthol) and 8.0 and 92.1 ng mL(-1) in nine cases (menthol). The sum values of free and conjugated substances ranged between 4.2 and 127.8 ng mL(-1) in 35 cases for neomenthol and 11.0 and 638.2 ng mL(-1) in 59 cases for menthol. Menthone and Isomenthone were not conjugated. These test results confirmed that the analysis of characteristic beverage aroma compounds, such as menthone, Isomenthone, neomenthol and menthol, can be used for specific verification of post-offence alcohol consumption claims.
Libor Červený - One of the best experts on this subject based on the ideXlab platform.
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the kinetics of stereoselective hydrogenation of menthone and Isomenthone mixture using nickel catalysts
Applied Catalysis A-general, 2000Co-Authors: Pavel Kukula, Libor ČervenýAbstract:Abstract The kinetics of the catalytic hydrogenation of optically active mixture of (−)-menthone and (+)-Isomenthone was studied. Raney nickel and Ni/SiO2 were used as catalysts. Catalysts modified with tartaric acid (TA) were tested as well. Various isomers were produced in these reactions, especially (+)-neomenthol and (+)-neoisomenthol. Small amount of (−)-menthol was produced, the yield of (−)-isomenthol was minimal. An isomerization of (−)-menthone and (+)-Isomenthone occurred during these reactions. Isomerizations among individual menthol isomers were not detectable under the given reaction conditions. Based on the acquired experimental data, a kinetic model of the Langmuir–Hinshelwood type was created. This model was further continuously adjusted and simplified as to describe the experimental data and acquire optimal kinetic model parameters.
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The kinetics of stereoselective hydrogenation of (−)-menthone and (+)-Isomenthone mixture using nickel catalysts
Applied Catalysis A-general, 2000Co-Authors: Pavel Kukula, Libor ČervenýAbstract:Abstract The kinetics of the catalytic hydrogenation of optically active mixture of (−)-menthone and (+)-Isomenthone was studied. Raney nickel and Ni/SiO2 were used as catalysts. Catalysts modified with tartaric acid (TA) were tested as well. Various isomers were produced in these reactions, especially (+)-neomenthol and (+)-neoisomenthol. Small amount of (−)-menthol was produced, the yield of (−)-isomenthol was minimal. An isomerization of (−)-menthone and (+)-Isomenthone occurred during these reactions. Isomerizations among individual menthol isomers were not detectable under the given reaction conditions. Based on the acquired experimental data, a kinetic model of the Langmuir–Hinshelwood type was created. This model was further continuously adjusted and simplified as to describe the experimental data and acquire optimal kinetic model parameters.
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The kinetics of stereoselective hydrogenation of (-)-menthone and (+)-Isomenthone mixture using nickel catalysts
Applied Catalysis A-general, 2000Co-Authors: Pavel Kukula, Libor ČervenýAbstract:Abstract The kinetics of the catalytic hydrogenation of optically active mixture of (−)-menthone and (+)-Isomenthone was studied. Raney nickel and Ni/SiO2 were used as catalysts. Catalysts modified with tartaric acid (TA) were tested as well. Various isomers were produced in these reactions, especially (+)-neomenthol and (+)-neoisomenthol. Small amount of (−)-menthol was produced, the yield of (−)-isomenthol was minimal. An isomerization of (−)-menthone and (+)-Isomenthone occurred during these reactions. Isomerizations among individual menthol isomers were not detectable under the given reaction conditions. Based on the acquired experimental data, a kinetic model of the Langmuir–Hinshelwood type was created. This model was further continuously adjusted and simplified as to describe the experimental data and acquire optimal kinetic model parameters.
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stereoselective hydrogenation of menthone and Isomenthone mixture using nickel catalysts
Research on Chemical Intermediates, 2000Co-Authors: Pavel Kukula, Libor ČervenýAbstract:The catalytic hydrogenation of an optically active mixture of (−)-menthone and (+)-Isomenthone was studied. The catalysts Raney nickel and Ni/SiO2 were used for these hydrogenations. Catalysts modified with (2R,3R)-(+)-tartaric acid were tested as well. Various non-equilibrium mixtures of isomers were produced by means of these reactions, especially mixtures containing the less stable menthol isomers, (+)-neomenthol and (+)-neoisomenthol. (−)-Menthol was produced during these reactions to a limited extent, the production of (−)-isomenthol was barcly existent. Isomerization of (−)-menthone and (+)-Isomenthone occurred during these reactions. Isomerizations among individual isomers were barely detectable. The catalysts used showed a very low activity under the given reaction conditions.
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Stereoselective hydrogenation of (−)-menthone and (+)-Isomenthone mixture using nickel catalysts
Research on Chemical Intermediates, 2000Co-Authors: Pavel Kukula, Libor ČervenýAbstract:The catalytic hydrogenation of an optically active mixture of (−)-menthone and (+)-Isomenthone was studied. The catalysts Raney nickel and Ni/SiO2 were used for these hydrogenations. Catalysts modified with (2R,3R)-(+)-tartaric acid were tested as well. Various non-equilibrium mixtures of isomers were produced by means of these reactions, especially mixtures containing the less stable menthol isomers, (+)-neomenthol and (+)-neoisomenthol. (−)-Menthol was produced during these reactions to a limited extent, the production of (−)-isomenthol was barcly existent. Isomerization of (−)-menthone and (+)-Isomenthone occurred during these reactions. Isomerizations among individual isomers were barely detectable. The catalysts used showed a very low activity under the given reaction conditions.
Virginia Vetere - One of the best experts on this subject based on the ideXlab platform.
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hydrogenation of menthone Isomenthone and pulegone with platinum tin catalysts
Catalysis Letters, 2002Co-Authors: Virginia Vetere, Gerardo Fabian Santori, Albertina G Moglioni, Graciela Moltrasio Y Iglesias, Monica L Casella, Osmar A FerrettiAbstract:The hydrogenation of (-)-menthone, (+)-Isomenthone, and (+)-pulegone over SiO2-supported Pt and Pt-Sn catalysts was studied in this work. The modification with tin was performed by means of the techniques of surface organometallic chemistry on metals. This way of modifying the catalysts allowed stereoisomers of menthol to be obtained in a one-step process. The hydrogenation of these terpenones was favored by the presence of tin in the bimetallic phase.
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Hydrogenation of (-)-menthone, (+)-Isomenthone, and (+)-pulegone with platinum/tin catalysts
Catalysis Letters, 2002Co-Authors: Virginia Vetere, Gerardo Fabian Santori, Albertina G Moglioni, Monica L Casella, Graciela Y. Moltrasio Iglesias, Osmar A FerrettiAbstract:The hydrogenation of (-)-menthone, (+)-Isomenthone, and (+)-pulegone over SiO2-supported Pt and Pt-Sn catalysts was studied in this work. The modification with tin was performed by means of the techniques of surface organometallic chemistry on metals. This way of modifying the catalysts allowed stereoisomers of menthol to be obtained in a one-step process. The hydrogenation of these terpenones was favored by the presence of tin in the bimetallic phase.
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Hydrogenation of (–)-Menthone, (+)-Isomenthone, and (+)-Pulegone with Platinum/Tin Catalysts
Catalysis Letters, 2002Co-Authors: Virginia Vetere, Gerardo Fabian Santori, Albertina G Moglioni, Monica L Casella, Graciela Y. Moltrasio Iglesias, Osmar A FerrettiAbstract:The hydrogenation of (-)-menthone, (+)-Isomenthone, and (+)-pulegone over SiO_2-supported Pt and Pt-Sn catalysts was studied in this work. The modification with tin was performed by means of the techniques of surface organometallic chemistry on metals. This way of modifying the catalysts allowed stereoisomers of menthol to be obtained in a one-step process. The hydrogenation of these terpenones was favored by the presence of tin in the bimetallic phase.
