The Experts below are selected from a list of 552 Experts worldwide ranked by ideXlab platform
Mark A Sefton - One of the best experts on this subject based on the ideXlab platform.
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the consumption of damascenone during early wine maturation
Developments in food science, 2006Co-Authors: Mark A Sefton, Gordon M Elsey, Merran A Daniel, Michael V PerkinsAbstract:Damascenone has been shown to undergo reaction with common wine components. Following the action of Acid and heat alone, two bicyclic compounds were isolated. Two C9 adducts, resulting from the addition of water and ethanol were also observed. Their formation was shown to be reversible. When treated with SO2 (introduced as its aqueous equivalent, bisulfite) the concentration of damascenone rapidly decreased to zero. A C9 Sulfonic Acid Derivative was isolated and characterised, and its formation from damascenone shown to be irreversible in the presence of acetaldehyde.
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fate of damascenone in wine the role of so2
Journal of Agricultural and Food Chemistry, 2004Co-Authors: Merran A Daniel, Gordon M Elsey, Michael V Perkins, Dimitra L Capone, Mark A SeftonAbstract:Damascenone has been shown to undergo reaction with common wine components. Following the action of Acid and heat alone, two bicyclic compounds, 4,9,9-trimethyl-8-methylenebicyclo[3.3.1]non-6-en-2-one (2) and 4,4,9-trimethyl-8-methylenebicyclo[3.3.1] non-6-en-2-one (3), were isolated. However, this conversion takes place only very slowly, if at all, under milder conditions (45 degrees C). When treated with a variety of nucleophiles at pH 3.0 and 5.5, the concentration of damascenone in buffered aqueous ethanol decreased by minor amounts (10-20%) except for cysteine and 2-mercaptoethanol addition at pH 5.5 (approximately 40 and approximately 30%, respectively) and SO2 (>90% at pH 3.0; 100% at pH 5.5). An adduct from this last combination was prepared and shown to be the C9 Sulfonic Acid Derivative of damascenone. A detailed investigation into the effect of SO2 demonstrated that loss of damascenone in model wine was directly related to the concentration of added SO2 but was essentially unaffected by small changes in pH.
Merran A Daniel - One of the best experts on this subject based on the ideXlab platform.
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the consumption of damascenone during early wine maturation
Developments in food science, 2006Co-Authors: Mark A Sefton, Gordon M Elsey, Merran A Daniel, Michael V PerkinsAbstract:Damascenone has been shown to undergo reaction with common wine components. Following the action of Acid and heat alone, two bicyclic compounds were isolated. Two C9 adducts, resulting from the addition of water and ethanol were also observed. Their formation was shown to be reversible. When treated with SO2 (introduced as its aqueous equivalent, bisulfite) the concentration of damascenone rapidly decreased to zero. A C9 Sulfonic Acid Derivative was isolated and characterised, and its formation from damascenone shown to be irreversible in the presence of acetaldehyde.
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fate of damascenone in wine the role of so2
Journal of Agricultural and Food Chemistry, 2004Co-Authors: Merran A Daniel, Gordon M Elsey, Michael V Perkins, Dimitra L Capone, Mark A SeftonAbstract:Damascenone has been shown to undergo reaction with common wine components. Following the action of Acid and heat alone, two bicyclic compounds, 4,9,9-trimethyl-8-methylenebicyclo[3.3.1]non-6-en-2-one (2) and 4,4,9-trimethyl-8-methylenebicyclo[3.3.1] non-6-en-2-one (3), were isolated. However, this conversion takes place only very slowly, if at all, under milder conditions (45 degrees C). When treated with a variety of nucleophiles at pH 3.0 and 5.5, the concentration of damascenone in buffered aqueous ethanol decreased by minor amounts (10-20%) except for cysteine and 2-mercaptoethanol addition at pH 5.5 (approximately 40 and approximately 30%, respectively) and SO2 (>90% at pH 3.0; 100% at pH 5.5). An adduct from this last combination was prepared and shown to be the C9 Sulfonic Acid Derivative of damascenone. A detailed investigation into the effect of SO2 demonstrated that loss of damascenone in model wine was directly related to the concentration of added SO2 but was essentially unaffected by small changes in pH.
H Aoki - One of the best experts on this subject based on the ideXlab platform.
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preconcentration of lead ii in environmental waters using a chelating resin and subsequent determination as a resin water suspension by hydride generation atomic absorption spectrometry
Journal of Analytical Atomic Spectrometry, 1993Co-Authors: M Chikuma, H AokiAbstract:A method is described for the determination of lead(II) in environmental water samples by hydride generation atomic absorption spectrometry combined with a resin–water suspension sampling technique after preconcentration using a chelate-forming resin. The chelate-forming resin was prepared by the modification of a commercially available anion-exchange resin and the sodium salt of a Sulfonic Acid Derivative of dithizone, disodium (4-sulfophenyl)-1-[2-(4-sulfophenyl)hydrazide]diazenecarbothioate (DzS). Lead(II) was found to be collected completely in the pH range between 6.3 and 10 by the DzS-loaded resin. When the aqueous suspension of metal-adsorbed resin was introduced into a hydride generation system with 1 mol l–1 HCl, 15% v/v H2O2 and 5% m/v NaBH4(in 0.5% m/v NaOH), lead(II) in the resin was converted into its hydride effectively. Neither DzS nor DzS-loaded resin interferes with the generation of lead hydride. The recovery and relative standard deviation were found to be 104 and 4%(n=4), respectively, when 2.5 µg of lead(II) was spiked into 1 l of distilled water. The proposed method was applied to the determination of trace amounts of lead(II) in environmental water samples.
Gordon M Elsey - One of the best experts on this subject based on the ideXlab platform.
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the consumption of damascenone during early wine maturation
Developments in food science, 2006Co-Authors: Mark A Sefton, Gordon M Elsey, Merran A Daniel, Michael V PerkinsAbstract:Damascenone has been shown to undergo reaction with common wine components. Following the action of Acid and heat alone, two bicyclic compounds were isolated. Two C9 adducts, resulting from the addition of water and ethanol were also observed. Their formation was shown to be reversible. When treated with SO2 (introduced as its aqueous equivalent, bisulfite) the concentration of damascenone rapidly decreased to zero. A C9 Sulfonic Acid Derivative was isolated and characterised, and its formation from damascenone shown to be irreversible in the presence of acetaldehyde.
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fate of damascenone in wine the role of so2
Journal of Agricultural and Food Chemistry, 2004Co-Authors: Merran A Daniel, Gordon M Elsey, Michael V Perkins, Dimitra L Capone, Mark A SeftonAbstract:Damascenone has been shown to undergo reaction with common wine components. Following the action of Acid and heat alone, two bicyclic compounds, 4,9,9-trimethyl-8-methylenebicyclo[3.3.1]non-6-en-2-one (2) and 4,4,9-trimethyl-8-methylenebicyclo[3.3.1] non-6-en-2-one (3), were isolated. However, this conversion takes place only very slowly, if at all, under milder conditions (45 degrees C). When treated with a variety of nucleophiles at pH 3.0 and 5.5, the concentration of damascenone in buffered aqueous ethanol decreased by minor amounts (10-20%) except for cysteine and 2-mercaptoethanol addition at pH 5.5 (approximately 40 and approximately 30%, respectively) and SO2 (>90% at pH 3.0; 100% at pH 5.5). An adduct from this last combination was prepared and shown to be the C9 Sulfonic Acid Derivative of damascenone. A detailed investigation into the effect of SO2 demonstrated that loss of damascenone in model wine was directly related to the concentration of added SO2 but was essentially unaffected by small changes in pH.
M Chikuma - One of the best experts on this subject based on the ideXlab platform.
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preconcentration of lead ii in environmental waters using a chelating resin and subsequent determination as a resin water suspension by hydride generation atomic absorption spectrometry
Journal of Analytical Atomic Spectrometry, 1993Co-Authors: M Chikuma, H AokiAbstract:A method is described for the determination of lead(II) in environmental water samples by hydride generation atomic absorption spectrometry combined with a resin–water suspension sampling technique after preconcentration using a chelate-forming resin. The chelate-forming resin was prepared by the modification of a commercially available anion-exchange resin and the sodium salt of a Sulfonic Acid Derivative of dithizone, disodium (4-sulfophenyl)-1-[2-(4-sulfophenyl)hydrazide]diazenecarbothioate (DzS). Lead(II) was found to be collected completely in the pH range between 6.3 and 10 by the DzS-loaded resin. When the aqueous suspension of metal-adsorbed resin was introduced into a hydride generation system with 1 mol l–1 HCl, 15% v/v H2O2 and 5% m/v NaBH4(in 0.5% m/v NaOH), lead(II) in the resin was converted into its hydride effectively. Neither DzS nor DzS-loaded resin interferes with the generation of lead hydride. The recovery and relative standard deviation were found to be 104 and 4%(n=4), respectively, when 2.5 µg of lead(II) was spiked into 1 l of distilled water. The proposed method was applied to the determination of trace amounts of lead(II) in environmental water samples.
