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Detalles de la revista
Formato
Revista
eISSN
2719-9509
Publicado por primera vez
01 Jan 1992
Periodo de publicación
4 veces al año
Idiomas
Inglés

Buscar

Volumen 21 (2005): Edición 7 (October 2005)

Detalles de la revista
Formato
Revista
eISSN
2719-9509
Publicado por primera vez
01 Jan 1992
Periodo de publicación
4 veces al año
Idiomas
Inglés

Buscar

6 Artículos
Acceso abierto

Analysis of Minor Alkaloids in Tobacco: A Collaborative Study

Publicado en línea: 30 Dec 2014
Páginas: 369 - 379

Resumen

Abstract

A collaborative study regarding the analysis of minor alkaloids in tobacco and tobacco products was initiated by the Analytical Methods Committee of the Tobacco Science Research Conference (TSRC). One purpose of the study was to assess the reliability of methods used for the analysis of minor alkaloids and nicotine in tobacco and tobacco products, as practiced in different laboratories. A second purpose was to select a preferred method or to develop a hybrid method based on the best elements from the procedures currently used for the analysis of minor alkaloids. A hybrid method was developed and its results compared with the values from existing methods. The hybrid method proves to be reliable, has good repeatability, and is easy to implement. This new method can be used as a reference procedure for minor alkaloids and nicotine analysis using either flame ionization (FID) or mass spectrometric (MS) detection. A comparison with the older techniques shows that the hybrid method considerably improved the repeatability, but only marginally increased the reproducibility for different laboratories. This may be, in part, because any new method requires some time to become fully standardized and reliable. Also, the contribution of other sources of variation such as different standards and different equipment may have limited the improvement in reproducibility.

Acceso abierto

Separation and Identification of Sucrose Esters from Turkish Tobacco Using Liquid Chromatography-Mass Spectrometry

Publicado en línea: 30 Dec 2014
Páginas: 381 - 389

Resumen

Abstract

Tetra-acylated sucrose esters (SE) in Turkish tobacco extracts have been separated and identified using liquid chromatography-mass spectrometry (LC-MS). An enriched fraction of SE from semi-preparative normal phase liquid chromatography of the methylene chloride extract was chosen for characterization. Several types of SE were observed that differed primarily in placement of the acyl functionality on either the glucose or the fructose fragment. In addition to acetyl, the other three observed acyl substitution patterns were governed by the presence of butyl, pentyl, and hexyl alkyl substituents. Within each type of SE, there were observed several homologs differing by a methylene moiety. Within each homolog, a number of isomeric components were found. The presence of unsaturation in one of the acyl alkyl substituents gave rise to another homologous series wherein isomers of the same mass were discovered. The information on the substitution pattern of SE using this new LC-MS approach was very similar to that obtained previously on tobacco samples employing gas chromatography-mass spectrometry (GC-MS) of derivatized sucrose esters.

Acceso abierto

A Low-Cost System for Measuring ppb-Level NO2

Publicado en línea: 30 Dec 2014
Páginas: 390 - 401

Resumen

Abstract

A low-cost system to measure low-level nitrogen dioxide (NO2) in an atmosphere was developed. Its major component included a sensor comprising filter paper treated with 3,3’-dimethylbenzidine (o-tolidine), a compound that reacts with NO2to generate color proportional to the NO2contacted. In addition to the system development, its utility was optimized and the characteristics of the sensor were defined. Originally developed to determine the NO2levels during direct-fired tobacco curing, the system may be used to determine the NO2levels in other situations.

Acceso abierto

Numerical Simulation of a Cigarette during Smoking

Publicado en línea: 30 Dec 2014
Páginas: 403 - 416

Resumen

Abstract

A mathematical model for a lit cigarette is derived, which predicts pressure, flow velocity, temperature and gas concentrations inside and outside the cigarette. It consists of a continuum-mechanical model for the flow and a discrete model for the chemical reactions occurring in the tobacco particles.

The cigarette model is simulated for a cigarette in a vertical position by methods known as computational fluid dynamics (CFD). Calculated temperature and gas concentration profiles are compared to measured data from the literature for smouldering, puffing and steady-draw. For thermo-physical properties, such as temperature fields and burn rates, a good correspondence with experimental data was found. The correspondence with measured gas concentration profiles was also acceptable, even though the reaction model is rather simple. The results show the importance of including the surroundings of the cigarette in the computational domain.

Secondly, a cigarette in a horizontal position is simulated both for free smouldering and for smouldering on a substrate, as occurs, for example, during the ignition strength test. The results show certain qualitative differences between the two smouldering regimes in the flow pattern outside the cigarette and in the transfer of heat to the surroundings and to the substrate.

The proposed model offers two main advantages. Firstly, it does not need the input of any data, that can only be measured if the cigarette has been lit, such as temperature fields or burn rates. Secondly, with this model all types of smoking regimes such as smouldering, puffing and steady-draw can be simulated without making any modifications to the mathematical model or its parameters. Only the boundary conditions need to be adapted.

Acceso abierto

Commentary: DIN Technical Report 133 - Toxicological Evaluation of Additives for Tobacco Products - A Guide

Publicado en línea: 30 Dec 2014
Páginas: 417 - 418

Resumen

Acceso abierto

Conference Report: Experimental Assessment of the Toxicological Effects of Inhaled Complex Mixtures on the Respiratory System - Feasability and Limitations, 23-25 April 2005, Barcelona, Spain

Publicado en línea: 30 Dec 2014
Páginas: 419 - 422

Resumen

6 Artículos
Acceso abierto

Analysis of Minor Alkaloids in Tobacco: A Collaborative Study

Publicado en línea: 30 Dec 2014
Páginas: 369 - 379

Resumen

Abstract

A collaborative study regarding the analysis of minor alkaloids in tobacco and tobacco products was initiated by the Analytical Methods Committee of the Tobacco Science Research Conference (TSRC). One purpose of the study was to assess the reliability of methods used for the analysis of minor alkaloids and nicotine in tobacco and tobacco products, as practiced in different laboratories. A second purpose was to select a preferred method or to develop a hybrid method based on the best elements from the procedures currently used for the analysis of minor alkaloids. A hybrid method was developed and its results compared with the values from existing methods. The hybrid method proves to be reliable, has good repeatability, and is easy to implement. This new method can be used as a reference procedure for minor alkaloids and nicotine analysis using either flame ionization (FID) or mass spectrometric (MS) detection. A comparison with the older techniques shows that the hybrid method considerably improved the repeatability, but only marginally increased the reproducibility for different laboratories. This may be, in part, because any new method requires some time to become fully standardized and reliable. Also, the contribution of other sources of variation such as different standards and different equipment may have limited the improvement in reproducibility.

Acceso abierto

Separation and Identification of Sucrose Esters from Turkish Tobacco Using Liquid Chromatography-Mass Spectrometry

Publicado en línea: 30 Dec 2014
Páginas: 381 - 389

Resumen

Abstract

Tetra-acylated sucrose esters (SE) in Turkish tobacco extracts have been separated and identified using liquid chromatography-mass spectrometry (LC-MS). An enriched fraction of SE from semi-preparative normal phase liquid chromatography of the methylene chloride extract was chosen for characterization. Several types of SE were observed that differed primarily in placement of the acyl functionality on either the glucose or the fructose fragment. In addition to acetyl, the other three observed acyl substitution patterns were governed by the presence of butyl, pentyl, and hexyl alkyl substituents. Within each type of SE, there were observed several homologs differing by a methylene moiety. Within each homolog, a number of isomeric components were found. The presence of unsaturation in one of the acyl alkyl substituents gave rise to another homologous series wherein isomers of the same mass were discovered. The information on the substitution pattern of SE using this new LC-MS approach was very similar to that obtained previously on tobacco samples employing gas chromatography-mass spectrometry (GC-MS) of derivatized sucrose esters.

Acceso abierto

A Low-Cost System for Measuring ppb-Level NO2

Publicado en línea: 30 Dec 2014
Páginas: 390 - 401

Resumen

Abstract

A low-cost system to measure low-level nitrogen dioxide (NO2) in an atmosphere was developed. Its major component included a sensor comprising filter paper treated with 3,3’-dimethylbenzidine (o-tolidine), a compound that reacts with NO2to generate color proportional to the NO2contacted. In addition to the system development, its utility was optimized and the characteristics of the sensor were defined. Originally developed to determine the NO2levels during direct-fired tobacco curing, the system may be used to determine the NO2levels in other situations.

Acceso abierto

Numerical Simulation of a Cigarette during Smoking

Publicado en línea: 30 Dec 2014
Páginas: 403 - 416

Resumen

Abstract

A mathematical model for a lit cigarette is derived, which predicts pressure, flow velocity, temperature and gas concentrations inside and outside the cigarette. It consists of a continuum-mechanical model for the flow and a discrete model for the chemical reactions occurring in the tobacco particles.

The cigarette model is simulated for a cigarette in a vertical position by methods known as computational fluid dynamics (CFD). Calculated temperature and gas concentration profiles are compared to measured data from the literature for smouldering, puffing and steady-draw. For thermo-physical properties, such as temperature fields and burn rates, a good correspondence with experimental data was found. The correspondence with measured gas concentration profiles was also acceptable, even though the reaction model is rather simple. The results show the importance of including the surroundings of the cigarette in the computational domain.

Secondly, a cigarette in a horizontal position is simulated both for free smouldering and for smouldering on a substrate, as occurs, for example, during the ignition strength test. The results show certain qualitative differences between the two smouldering regimes in the flow pattern outside the cigarette and in the transfer of heat to the surroundings and to the substrate.

The proposed model offers two main advantages. Firstly, it does not need the input of any data, that can only be measured if the cigarette has been lit, such as temperature fields or burn rates. Secondly, with this model all types of smoking regimes such as smouldering, puffing and steady-draw can be simulated without making any modifications to the mathematical model or its parameters. Only the boundary conditions need to be adapted.

Acceso abierto

Commentary: DIN Technical Report 133 - Toxicological Evaluation of Additives for Tobacco Products - A Guide

Publicado en línea: 30 Dec 2014
Páginas: 417 - 418

Resumen

Acceso abierto

Conference Report: Experimental Assessment of the Toxicological Effects of Inhaled Complex Mixtures on the Respiratory System - Feasability and Limitations, 23-25 April 2005, Barcelona, Spain

Publicado en línea: 30 Dec 2014
Páginas: 419 - 422

Resumen

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