Volume 20 (2003): Issue 6 (July 2003)

The potential effects of smoke pH on vapor-phase nicotine, or unprotonated nicotine, were investigated using a diffusion denuder method selected for its ability to quantitatively monitor vapor-phase nicotine in the presence of smoke particulate. For the purpose of this paper, the pH of the water-soluble fraction of mainstream cigarette smoke will be referred to as ‘smoke pH'. In this study, samples with different construction parameters affecting smoke pH were analyzed for percent vapor-phase nicotine. The smoke pH values ranged from 5.87 to 7.79. Percent initial vapor-phase nicotine values ranged from 0.4% to 1.5%. The range of the vapor-phase nicotine values for this study was (a) independent of smoke pH and (b) potentially dependent upon cigarette construction. In a second experiment, cigarettes with the same construction were used to repeat the analysis, thus eliminating construction as a variable. The tobacco was treated with varying levels of urea to give a range in smoke pH from 6.47 to 7.15. The determined initial vapor-phase nicotine values ranged from 0.4% to 2.1% of the total mainstream smoke nicotine. This variation was independent of smoke pH. It was determined in this study that (a) the maximum initial vapor-phase nicotine delivered to mainstream smoke was 2.1% of the total nicotine delivered for our cigarette samples and (b) the delivery of the unprotonated nicotine to mainstream smoke was not meaningfully affected by changes in smoke pH within the range studied.

The objective of this contribution is to characterise the distribution of adhesive between the plug wrap paper and the tipping paper on a finished cigarette. On the one hand, it is well known that this distribution influences various properties of the cigarette, but on the other hand, there are no methods available to completely determine this distribution. The area covered by adhesive, the amount of adhesive, and the thickness and position of the adhesive layer between the plug wrap and the tipping paper were chosen as essential quantities. Image analysis was used to evaluate the area covered by adhesive, and the amount of adhesive between the papers. The thickness and position of the adhesive layer were determined by processing pictures of paper cross-sections obtained with a time-of-flight secondary ion mass spectrometer (TOF-SIMS).

Coal temperatures affect the burn properties of cigarettes. Thermal imaging was used to determine the average maximum surface coal temperatures during smolder of cigarettes of different tobacco types. The thermal imaging camera was calibrated against a reference blackbody. An emissivity correction was necessary since the set point temperatures of the reference blackbody did not correspond to the measured temperatures of the reference blackbody. A 0.87 camera emissivity was applied to provide accurate coal temperatures at a corrected emissivity of approximately 1. The average maximum surface coal temperatures during smolder of unfiltered single-tobacco-type cigarettes and a commercial blend cigarette were determined (with the camera lens focused parallel to the cigarette), and no discernible differences among them were found. The calculated average maximum surface coal temperature during smolder for all cigarettes was 584 AA± 15 °C. During smolder, thermocouples were used to measure the temperature of the gas phase (along the central axis of coal), and the thermal imaging camera was used to measure the temperature of the solid phase of the coal's surface. Using thermocouples, the peak coal temperatures in the center of the coal during smolder for three filtered single-tobacco-type cigarettes were 736-744 °C. Peak coal temperatures, measured by thermal imaging, on the surface of the coal (with the camera lens focused coaxially with the coal and the ash removed) for the same three single-tobacco-type cigarettes had a range of 721-748 °C. There was good correspondence between the two techniques. These results confirm that during smolder the gas-phase temperature inside the coal (as measured with the thermocouple) and the solid-phase temperatures beneath the ash (as measured with the camera) are in near thermal equilibrium. With proper calibration, a thermal imaging system is a good alternative to thermocouples for measuring cigarette coal temperatures.

Ammonia is generated in mainstream smoke (MSS) from multiple precursors in tobacco such as amino acids, proteins, nitrates and ammonium salts. Ammonia derived from both the particulate and vapor phases is measured with the particulate phase contributing greater than 80% of the total ammonia. The general approach of the analytical methods involved the collection of MSS by either electrostatic precipitation (EP) or impingers with acidic solution combined with Cambridge filters (CF, 44 or 92 mm) and the analysis of ammonium cations by ion chromatography (IC) with a conductivity detector. The available results from both internal testing and external literature for 1R4F Kentucky reference cigarettes, smoked under Federal Trade Commission (FTC) puffing conditions, showed a wide range of yields from approximately 5 to 18 µg/cig of ammonia. To investigate possible causes for this wide range and to optimize the analytical method, several parameters deemed critical to the results were studied using 1R4F. They include the type of acids (hydrochloric acid, sulfuric acid and malic acid), acid strength (0.005 M to 0.1 M), trapping efficiency and sample stability. The study showed that the type and concentration of acids was not significantly related to the total ammonia content in MSS. The study also indicated that the size and type of trapping devices, such as CF pads, acid treated CF pads and EP tube, did not significantly affect the trapping efficiency.

We have investigated the effects of saline irrigation on growth and water relations of two sun-cured tobacco genotypes, Xp102 and Px107, which belong to the Xanthia and Perustitza tobacco ecotypes, respectively. We compared three commercial sea salt concentrations of the irrigation water (0.25%, 0.5%, and 1% w/v) plus a non-salinized control, corresponding to an electrical conductivity (ECw) of 4.4, 8.5, 15.7, 0.5 dS m^-1 and osmotic potentials of -0.22, -0.35, -0.73, -0.02 MPa, respectively. The EC_soil increased with the salinity of the irrigation water. At high salinity (1%), the soil where Px107 plants were grown showed a significantly higher salinity compared to the soil of Xp102. For both genotypes, the soil water content increased at increasing salinity and during the growth season. Increasing salinity progressively reduced the leaf turgor pressure and enhanced the cellular osmotic adjustment. The latter resulted to be more pronounced in Px107 compared to Xp102 (0.36 vs. 0.20 MPa). At higher salinity (0.5% and 1%), both genotypes showed reduced leaf surface area, dry matter accumulation, water use, net assimilation rate (NAR) and crop growth rate (CGR). Px107 roots were more sensitive than shoot to salinity (3% reduction per dS m^-1) and compared to Xp102 roots, which showed a reduced development only at 1% salinity. Assessment of plant salt tolerance according to the Maas and Hoffman model revealed a slope of 1-2% for both genotypes, indicating that these tobaccos are relatively more salt tolerant compared to other species.

Since the mid-1960s, various investigators, agencies, and institutions have disseminated lists of cigarette mainstream smoke (MSS) components reported to be tumorigenic on the basis of laboratory bioassays conducted under conditions significantly different from those encountered by the smoker during exposure to the components in the cigarette MSS aerosol. Since 1990, numerous lists of cigarette MSS components, defined as significant tumorigens, have been compiled by American Health Foundation personnel, Occupational Safety and Health Administration (OSHA), Fowles and Bates, and R.J. Reynolds R&D personnel. The purpose of most of the reports was to define human risk assessment and to dissuade smokers from smoking. Various investigators and agencies have frequently cited the earlier and/or the more recent lists of tumorigenic entities. The recent compilations, involving nearly 80 MSS components, suffer from serious deficiencies including: a) Use of per cigarette delivery ranges for specified components which often include analytical data from cigarettes manufactured in the 1950s and 1960s which are not comparable to lower-'tar’ yield cigarettes manufactured since the mid-1970s. b) Absence of standard analytical procedures for most of the listed components. c) Methodological considerations regarding bioassays used to determine tumorigenicity of the listed MSS components. d) Difficulty in extrapolating in vivo bioassay data obtained by non-inhalation modes of administration of a single compound to the human smoking situation involving inhalation of a complex aerosol containing that compound. e) Inhalation data inadequacies regarding the tumorigenicity of many of the components. f) Several tobacco smoke components are listed despite the fact their presence has not been confirmed, their MSS level has not been defined, or their MSS level is no longer relevant. g) Insufficient consideration of inhibitors of tumorigenesis and mutagenesis found in MSS. h) Difficulty in extrapolation of inhibition/anticarcinogenesis/antimutagenesis observed in a one-on-one in vivo situation to the complex MSS aerosol situation. j) Alternate exposures to many of the listed smoke components. k) Discrepancies among the lists. l) Discrepancies within the lists.A more appropriate use of the listing process is the identification of potential chemical targets for removal from, or inhibition in cigarette MSS.