Tom 18 (1999): Zeszyt 5 (July 1999)

This work is part of a long term study aimed at determining the odorous Volatile Organic Compounds (VOCs) in Environmental Tobacco Smoke (ETS) deposited on clothing. In this preliminary phase of the study sidestream smoke (SSS) rather than true ETS was used, for the following reasons. Firstly, the sampling system had to be modified in order to increase the concentration of odorous VOCs collected so that the later analytical stages could proceed. This meant that the sampling system was developed to collect concentrated SSS on cloth. Secondly, the cigarette butts were removed from the system so that they did not contribute to the odour; and thirdly the cloth was left to age for 48 hours. Therefore, technically, the study was the determination of the odorous VOCs in aged concentrated SSS deposited on cloth; this will be referred to as ‘aged SSS’ from this point onwards throughout this paper. This paper describes the method development of sampling and analysis techniques for odorous VOCs in aged SSS deposited on cloth. In addition, this paper demonstrates the processes of heartcutting and the mass spectral identification of odorous components using a concentrated tobacco steam distillate extract. A sampling chamber was constructed to allow the aged SSS to be deposited on the surface of the fabric, and to ensure that the amount of smoke deposited on the cloth was sufficiently high to conduct further analyses. The fabric was then desorbed via a purpose built purge- and-trap system to release the volatiles onto selected adsorbents. Each adsorbent in turn was solvent desorbed and a concentrated extract obtained. The aged SSS extracts were then directly injected into a multidimensional Gas Chromatography/Mass Spectrometry (GC/MS), and GC profiles obtained. These chromatographic profiles facilitate both the direct comparison of the range of VOCs trapped and desorbed from each adsorbent, and the identification of odorous regions when used in conjunction with the odour port. The aged SSS chromatograms presented in this paper only show the range of VOCs collected by the different adsorbents. Further experiments were also conducted with a concentrated tobacco steam distillate extract. These results were obtained by directly injecting the extract into the multidimensional GC/MS system, connected to an odour port. Volunteers were then asked to sensorially evaluate the odour of the extract and to identify any odorous notes during the analysis. Two concentrated tobacco steam distillate extract chromatograms are presented.

An equation to describe the water sorption isotherm of tobacco is developed based on a model of the tobacco-water system as a mixture or solid solution comprised of water and water binding sites of many different kinds. It is assumed that free water has an activity coefficient of one. The result is an equation that predicts moisture content as a function of relative humidity given the numbers of each of the different kinds of sites and the associated water binding equilibrium constants. It is shown that this multi-site equation reduces to a one site equation if the different kinds of water binding sites are symmetrically distributed with regard to their affinity for water. The result is a two parameter, average site equation that fits water sorption data for tobacco over the range of 10-80% relative humidity. The average site equation is identical to the equation derived by BRUNAUER, EMMETT and TELLER for binding to surface sites (1). The two models start from very different points of view but come to the same conclusion because they are ultimately based on thermodynamics which is indifferent as to the physical nature of the sites. Inferences as to the microscopic nature of water binding sites cannot be made from thermodynamic isotherm equations. In order to describe the effects of water on the physical properties of tobacco the solution analogy is extended further. If tobacco is a mixture or solution of unhydrated sites, hydrated sites and free water, then the value of a physical property should be a function of the concentrations of those species and the associated partial molar values of the property. As the total moisture content changes the distribution of species will change and, in turn, change the properties. Applications of this rationale are presented for heat capacity, thermal diffusivity and the kinetics of the Browning reaction. The results demonstrate that the parameters derived from water sorption data play a more general role in the thermodynamics of the tobacco-water system.

In order to understand how the raw materials and processing contribute to the performance of the products, a mathematical model of pressure drop and ventilation in a lit cigarette has been developed. The model can be used to predict these parameters based on the geometry and properties of tobacco rod and filter, such as cigarette circumference, paper permeability, and design of filter vent rows. The model can be used to evaluate the contributions of variable components to the changes of pressure drop and ventilation of a lit cigarette.

In order to judge the quality of tobacco leaf, it is necessary to conduct sensory smoke evaluations. However, these are subjective and the results are difficult to quantify. Therefore, we have attempted to establish a quantitative method for evaluating tobacco quality by comparing results of headspace analysis. Forty-seven leaf samples of different types (flue-cured, Burley, Oriental) were analyzed. The first step in this study was to have a panel of experts smoke cigarettes made from the test tobaccos and have them evaluate 10 sensory attributes. The scores were then analyzed by the technique of principal component analysis (PCA). Results showed that the score for the flavor note attribute indicated the type of tobacco and the scores of the other 9 attributes were combined as a total to indicate smoking quality. Following the sensory study, headspace vapors of the test tobaccos were analyzed with a headspace sampler, gas chromatography, mass spectroscopy system (HS-GC-MS), in which the gas sampling loop and the HS-GC transfer line were deactivated. In order to obtain conditions for good reproducibility, the heating temperature and time of the headspace vials were examined. PCA was performed for the headspace vapor (HSV) analysis results for 31 selected peaks. The first and second principal components could be used to classify tobacco types. The third principal component partially indicated differences of smoking qualities. Finally, multiple regression analysis was performed on the HSV analysis results in order to estimate the smoking quality scores. The regression model of all samples combined had a low regression coefficient. Then, we separated the results of the three tobacco types, as we considered that the headspace data might reveal information about the classifications themselves. The final outcome was a regression model that could be applied to each type with a higher accuracy. The variables that entered the models were compared.