The Experts below are selected from a list of 1677 Experts worldwide ranked by ideXlab platform
Antonio O S S Rangel - One of the best experts on this subject based on the ideXlab platform.
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development of a gas diffusion multicommuted flow injection system for the determination of sulfur dioxide in Wines comparing malachite green and pararosaniline chemistries
Journal of Agricultural and Food Chemistry, 2009Co-Authors: Sara M Oliveira, Teresa I M S Lopes, Ildiko V Toth, Antonio O S S RangelAbstract:A flow system based on the multicommutation concept was developed for the determination of free and total sulfur dioxide in Table Wines, exploiting gas diffusion separation and spectrophotometric d...
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a gas diffusion sequential injection system for the determination of sulphur dioxide in Wines
Analytica Chimica Acta, 2001Co-Authors: Marcela A Segundo, Antonio O S S RangelAbstract:Abstract In the present work, a sequential injection system with spectrophotometric detection was developed for the determination of free and total sulphur dioxide in Wines. It was based on the formation of a coloured product from the reaction among SO2, formaldehyde and pararosaniline. A gas diffusion unit (GDU) was incorporated into the manifold to prevent the wine matrix interference in the spectrophotometric measurement. An acid solution was added to the sample prior to its passage through the donor channel of the GDU to promote gaseous SO2 formation. For the free SO2 determination, the sample was directly aspirated into the holding coil; for the total SO2 determination, the sample was processed after previous in-line hydrolysis of bound SO2 with an alkali solution. Two second-order calibration curves were established, defining two concentration ranges: 2–40 mg l−1 for the free SO2 determination and 25–250 mg l−1 for the total SO2 determination. Relative standard deviations (n=10) were lower than 1.2% for the determination of free SO2 and lower than 2.3% for the determination of total SO2. The sample frequency was about 16 h−1. This methodology was applied to the determination of free and total sulphur dioxide in 10 Table Wines and the results were statistically comparable with those furnished by the recommended procedure.
Margarida A Ferreira - One of the best experts on this subject based on the ideXlab platform.
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combined ion pair extraction and gas chromatography mass spectrometry for the simultaneous determination of diamines polyamines and aromatic amines in port wine and grape juice
Journal of Chromatography A, 2000Co-Authors: Jose O Fernandes, Margarida A FerreiraAbstract:An accurate and very sensitive method which allows for the simultaneous determination of the diamines (1,3-diaminopropane, putrescine and cadaverine), of the polyamines (spermidine and spermine), and of the aromatic amines (beta-phenylethylamine and tyramine) found in Port Wines and corresponding grape juices is presented. Sample clean-up consisted of the extraction of the amines with the ion-pairing reagent bis-2-ethylhexylphosphate dissolved in chloroform followed by a back-extraction with 0.1 M HCl. The hydrochloric extract obtained was dried and the amines were further derivatized with heptafluorobutyric anhydride and analyzed by GC-MS in the selected ion-monitoring mode, with a total run time of 18 min. Under the adopted conditions, the extraction of all the studied compounds was almost complete and the obtained extracts were free of potential interferents present in the samples, namely sugars, and most of the amino acids and polyphenols. Via the use of a set of five selected internal standards (amphetamine, [2H8]putrescine, 1,7-diaminoheptane, norspermidine and norspermine), the data obtained from the linearity, repeatability and recovery experiments were very good for all the compounds assayed. The corresponding limits of detection were invariably below 10 microg l(-1). The method was successfully applied to measure the content of biogenic amines in twelve young and five aged Port wine samples, eleven grape juice samples as well as in ten Portuguese red and white Table Wines. Results are presented and briefly discussed.
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combined ion pair extraction and gas chromatography mass spectrometry for the simultaneous determination of diamines polyamines and aromatic amines in port wine and grape juice
Journal of Chromatography A, 2000Co-Authors: Jose O Fernandes, Margarida A FerreiraAbstract:An accurate and very sensitive method which allows for the simultaneous determination of the diamines (1,3-diaminopropane, putrescine and cadaverine), of the polyamines (spermidine and spermine), and of the aromatic amines (β-phenylethylamine and tyramine) found in Port Wines and corresponding grape juices is presented. Sample clean-up consisted of the extraction of the amines with the ion-pairing reagent bis-2-ethylhexylphosphate dissolved in chloroform followed by a back-extraction with 0.1 M HCl. The hydrochloric extract obtained was dried and the amines were further derivatized with heptafluorobutyric anhydride and analyzed by GC–MS in the selected ion-monitoring mode, with a total run time of 18 min. Under the adopted conditions, the extraction of all the studied compounds was almost complete and the obtained extracts were free of potential interferents present in the samples, namely sugars, and most of the aminoacids and polyphenols. Via the use of a set of five selected internal standards (amphetamine, [2H8]putrescine, 1,7-diaminoheptane, norspermidine and norspermine), the data obtained from the linearity, repeatability and recovery experiments were very good for all the compounds assayed. The corresponding limits of detection were invariably below 10 μg l−1. The method was successfully applied to measure the content of biogenic amines in twelve young and five aged Port wine samples, eleven grape juice samples as well as in ten Portuguese red and white Table Wines. Results are presented and briefly discussed.
Sara M Oliveira - One of the best experts on this subject based on the ideXlab platform.
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development of a gas diffusion multicommuted flow injection system for the determination of sulfur dioxide in Wines comparing malachite green and pararosaniline chemistries
Journal of Agricultural and Food Chemistry, 2009Co-Authors: Sara M Oliveira, Teresa I M S Lopes, Ildiko V Toth, Antonio O S S RangelAbstract:A flow system based on the multicommutation concept was developed for the determination of free and total sulfur dioxide in Table Wines, exploiting gas diffusion separation and spectrophotometric d...
Jose O Fernandes - One of the best experts on this subject based on the ideXlab platform.
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combined ion pair extraction and gas chromatography mass spectrometry for the simultaneous determination of diamines polyamines and aromatic amines in port wine and grape juice
Journal of Chromatography A, 2000Co-Authors: Jose O Fernandes, Margarida A FerreiraAbstract:An accurate and very sensitive method which allows for the simultaneous determination of the diamines (1,3-diaminopropane, putrescine and cadaverine), of the polyamines (spermidine and spermine), and of the aromatic amines (beta-phenylethylamine and tyramine) found in Port Wines and corresponding grape juices is presented. Sample clean-up consisted of the extraction of the amines with the ion-pairing reagent bis-2-ethylhexylphosphate dissolved in chloroform followed by a back-extraction with 0.1 M HCl. The hydrochloric extract obtained was dried and the amines were further derivatized with heptafluorobutyric anhydride and analyzed by GC-MS in the selected ion-monitoring mode, with a total run time of 18 min. Under the adopted conditions, the extraction of all the studied compounds was almost complete and the obtained extracts were free of potential interferents present in the samples, namely sugars, and most of the amino acids and polyphenols. Via the use of a set of five selected internal standards (amphetamine, [2H8]putrescine, 1,7-diaminoheptane, norspermidine and norspermine), the data obtained from the linearity, repeatability and recovery experiments were very good for all the compounds assayed. The corresponding limits of detection were invariably below 10 microg l(-1). The method was successfully applied to measure the content of biogenic amines in twelve young and five aged Port wine samples, eleven grape juice samples as well as in ten Portuguese red and white Table Wines. Results are presented and briefly discussed.
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combined ion pair extraction and gas chromatography mass spectrometry for the simultaneous determination of diamines polyamines and aromatic amines in port wine and grape juice
Journal of Chromatography A, 2000Co-Authors: Jose O Fernandes, Margarida A FerreiraAbstract:An accurate and very sensitive method which allows for the simultaneous determination of the diamines (1,3-diaminopropane, putrescine and cadaverine), of the polyamines (spermidine and spermine), and of the aromatic amines (β-phenylethylamine and tyramine) found in Port Wines and corresponding grape juices is presented. Sample clean-up consisted of the extraction of the amines with the ion-pairing reagent bis-2-ethylhexylphosphate dissolved in chloroform followed by a back-extraction with 0.1 M HCl. The hydrochloric extract obtained was dried and the amines were further derivatized with heptafluorobutyric anhydride and analyzed by GC–MS in the selected ion-monitoring mode, with a total run time of 18 min. Under the adopted conditions, the extraction of all the studied compounds was almost complete and the obtained extracts were free of potential interferents present in the samples, namely sugars, and most of the aminoacids and polyphenols. Via the use of a set of five selected internal standards (amphetamine, [2H8]putrescine, 1,7-diaminoheptane, norspermidine and norspermine), the data obtained from the linearity, repeatability and recovery experiments were very good for all the compounds assayed. The corresponding limits of detection were invariably below 10 μg l−1. The method was successfully applied to measure the content of biogenic amines in twelve young and five aged Port wine samples, eleven grape juice samples as well as in ten Portuguese red and white Table Wines. Results are presented and briefly discussed.
Andrew G Reynolds - One of the best experts on this subject based on the ideXlab platform.
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odor potency of aroma compounds in riesling and vidal blanc Table Wines and iceWines by gas chromatography olfactometry mass spectrometry
Journal of Agricultural and Food Chemistry, 2012Co-Authors: Amy J Bowen, Andrew G ReynoldsAbstract:This study aimed to elucidate the odor potency of aroma compounds in Riesling and Vidal blanc (syn. Vidal) Table Wines and iceWines from the Niagara Peninsula using stir bar sorptive extraction–gas...