Browse

1 - 10 of 1,235 items :

  • General Interest x
Clear All

Summary

α-Tocopherol, a type of vitamin E, has been known to be present in tobacco for many years. The compound is an antioxidant protecting cell membranes from oxidants. α-Tocopherol is transferred from tobacco into cigarette smoke, where it is also present. Analysis of α-tocopherol has been reported in a number of studies and in various matrices including tobacco and tobacco smoke. However, no recent publication describes a method for quantitative analysis of tocopherol in tobacco and in cigarette smoke, and many methods reported from previous studies were not published and only presented at conferences or communicated in internal company publications.

The goal of this study was to quantitate α-tocopherol and, if present, α-tocopheryl acetate in tobacco and in tobacco smoke. For this analysis, an original HPLC technique was developed and is described in this report. Both UV and MS/MS (MRM mode) were used as detection procedure for the analysis. The results obtained using UV detection were in very good agreement with the results obtained using MS/MS detection. The method has been applied for the analysis of a number of tobaccos, as well as the total particulate matter (TPM) from cigarettes made with the same tobaccos. Depending on tobacco type, the levels of α-tocopherol vary in tobacco between about 200 μg/g up to about 900 μg/g (“dry weight basis”). For ISO type smoking, the levels of α-tocopherol vary in TPM between about 2 μg/mg up to slightly above 4 μg/mg of TPM. For a cigarette generating TPM of about 10 mg/cig, the α-tocopherol is between about 20 μg/cig up to about 40 μg/cig. A relatively good correlation was obtained between the level of α-tocopherol in smoke (ISO type smoking) and the level of the compound in tobacco. α-Tocopheryl acetate was absent in tobacco.

OPEN ACCESS

Summary

In the absence of standards specific for testing the reduction robustness of the levels of harmful and potentially harmful constituents (HPHCs), the aerosol from the THS 2.2, a heated tobacco product, was compared with the mainstream smoke of the 3R4F reference cigarette over a broad range of machine-smoking regimes. The average reduction and the introduced concept of threshold limits of robust reduction were derived from HPHC concentrations, in mass per tobacco-stick normalized per total puff volume, to propose an alternative for the assessment of products where nicotine-adjusted yields would be inappropriate. In addition, this study explores the influence of 3R4F reference cigarette filter ventilation, and discusses the roles of temperature and precursors in the present context of robustness of HPHC reduction. Fifty-four HPHCs were analyzed under multiple regimes in THS 2.2 aerosol and 3R4F cigarette smoke. The average reduction of HPHC concentrations compared across all regimes characterized the robustness. Threshold limits of reduction of individual HPHCs were statistically determined across all regimes. The results observed under Health Canada Intense (HCI) and more intense regimes indicated that on average the reductions in HPHCs levels investigated in THS 2.2 aerosol were more than 90% and that the majority of the 54 HPHCs investigated in THS 2.2 aerosol showed more than 90% reduction. The robustness of THS 2.2 in maintaining the levels of reduction of representative HPHCs, whatever the puffing regime, can be quantified. The mass of HPHC per tobacco-stick normalized per total puff volume is a valuable approach to compare the robustness of the performance of a product over a large range of puffing conditions. Our findings will greatly complement the assessment for robustness of current and future similar products where classical approaches would present limitations.

Summary

Recently, capillary columns have been widely used in the methodology for the determination of water yields in smoke condensate, even though ISO 10362-1:1999, “Cigarettes - Determination of water in smoke condensates – Part 1: Gas chromatographic method” specifies a packed gas chromatographic column. As a result of a systematic review in 2015, ISO/TC126 decided to revise the standard to include the use of capillary columns.

The goal of this study was to confirm the comparability of water yields obtained from capillary column methodology to those yields from packed columns by the statistical analysis of yield data from the 24th Asia Collaborative Study which included 86 datasets submitted by 64 laboratories. After the exclusion of outliers by Cochran’s and Grubbs’ tests, the datasets were classified by GC column type and then mean water yields, and their repeatability and reproducibility were calculated for each type of column. No significant differences were observed in water yields between capillary and packed columns. Repeatability and reproducibility of water yields using capillary column were comparable to those using packed columns as described in ISO 10362-1:1999. From these results, it was confirmed that the capillary columns are an appropriate alternative to packed columns for the gas chromatographic procedure described in ISO 10362-1:1999.

Summary

Tobacco-specific nitrosamines (TSNAs) including nitrosoanabasine (NAB), nitrosoanatabine (NAT), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), and nitrosonornicotine (NNN) are naturally present at trace levels in tobacco. During tobacco processing, preparation of expanded tobacco, and when tobacco is used in heat-not-burn type cigarettes, the tobacco is exposed to different degrees of heat. Heating of tobacco has been reported in the literature to increase the level of TSNAs. Since the increase of TSNAs in heated tobacco is still not well understood, the present study evaluated TSNA levels in six types of tobacco as a function of moderate heat exposure. These tobaccos included: flue-cured lower stalk, flue-cured upper stalk (US), Burley lower stalk, Burley upper stalk (US), and two Oriental blends (Turkey, Greece, Bulgaria, Northern Republic Macedonia). Heating was performed in sealed glass tubes at oven temperatures of 100 °C, 150 °C, 200 °C, and 250 °C for time intervals of 2 min and 5 min. The temperatures inside the glass tubes were lower than the targets and were monitored separately as a function of glass tube heating. The study showed no meaningful differences within tobacco type (by stalk position) but showed considerable differences in the levels of TSNAs between different tobaccos, with the Burley tobaccos having the highest levels, and the Orientals the lowest. For all tobacco types, TSNAs increase to some extent when temperature increases. For 2-min heating, the increase in TSNAs is relatively small up to about 200 °C, but the levels almost double when the oven temperature increases to 250 °C. For 5-min heating, the increase in TSNAs starts at about 150 °C with a maximum at 200 °C which can reach more than double the initial TSNA level. Longer heating at 250 °C (5 min) starts to cause TSNAs decomposition and the levels are reduced.

OPEN ACCESS

Summary

The present study evaluated the in vitro extraction of benzo[a]pyrene (BaP) from moist snuff into water and into artificial saliva. A similar, previous study evaluated the levels of BaP that remained in the moist snuff after the extraction but did not measure the levels of BaP in the water or saliva extract. The previous study showed that the remaining levels of BaP in the solid material were between 96.3% and 109.6% relative to the initial level of BaP, when the snuff was washed with water and between 99.4% and 108.3% from the initial level of BaP, when the snuff was washed with both saliva and water. Nine moist snuff samples (eight being the same brands as evaluated in the previous study) were analyzed in the present study. Several improvements were made compared to the previous study regarding the extraction conditions. The extraction was performed for 1 h at 37 °C, using a mechanical agitator.

The previous study used a commercially available artificial saliva which had an adjusted pH but did not contain enzymes or salts. This saliva was replaced with complete artificial saliva containing salts, mucin and enzymes. The results indicated that the level of BaP extracted in 100 mL water from 5 g of moist snuff at 37 °C ranged between 1.0% and 1.7% of the initial level present in tobacco. For artificial saliva, the extracted level of BaP was between 2% and 3.9% from the initial level, depending on the moist snuff brand. Although the BaP level extracted from the moist snuff with artificial saliva remained very low, the surfactant character of artificial saliva increased BaP extraction relative to water by a factor of approximately two. This study supports the previous reported finding that the vast majority of BaP in moist snuff is not extracted in water or artificial saliva.

Summary

A diffusion denuder apparatus has been used to investigate the gas-particle partitioning of formaldehyde, acetaldehyde, acrolein and crotonaldehyde in cigarette mainstream smoke (MS), compounds that are of interest owing to their toxicity and near quantitative retention in the body during cigarette smoking. Formaldehyde showed the best performance in denuder experiments with simple aldehyde-air mixtures owing to the relatively fast rate of the heterogeneous reaction formaldehyde(g) + dinitrophenylhydrazine(s) → hydrazone(s). Analysis with the Gormley-Kennedy equation revealed that formaldehyde denuder removal approached, but did not attain, complete efficiency even under optimized operational conditions. Acetaldehyde, acrolein and crotonaldehyde were trapped with considerably lower efficiency than formaldehyde under the denuder conditions used, and more effective denuder wall coatings would be required to examine gas-particle partitioning of these other carbonyls. The proportion of formaldehyde in the smoke particulate phase initially entering the denuder was > 99%, but loss of formaldehyde from the smoke particles was relatively rapid leading to 35%–61% deposition over the denuder length. The temperature dependence of formaldehyde deposition in the denuder was well predicted using Henry's law constant for aqueous formaldehyde solutions. These observed properties of formaldehyde are primarily due to reversible reactions of formaldehyde with water in cigarette smoke leading to the much less volatile species methanediol, its oligomers and hydrate. These data suggest that cigarette smoke inhalation is likely to expose the deeper-lung generations of smokers to greater relative formaldehyde exposure, and greater genotoxic risk at those generations than might occur through inhalation of formaldehyde vapour alone.

Risk assessments of formaldehyde in cigarette smoke should be updated to recognise this modified risk profile.

Summary

Background

Combustion as well as pyrolysis of tobacco greatly affect the type and levels of toxicants in cigarette smoke. We previously developed an approach to combine simultaneous temperature and pressure measurements with fast in-situ microprobe chemical sampling inside a burning cigarette, producing a series of temperature and gas-flow velocity maps that characterize this dynamic system in response to externally applied air flow.

Aim

Two cigarette types differing only in diameter were puffed under ISO 3308 and Health Canada Intense (HCI) regimes to further understand the dynamic interaction of air flow and cigarette design parameters on tobacco combustion and pyrolysis by applying the thermophysical and thermo-chemical mapping approach.

Methods

Three types of sampling probes were inserted, which are thermocouple arrays for gas-phase temperature, quartz tubes for pressure measurement, and a heated sampling microprobe coupled to a single-photon soft ionisation mass spectrometer for chemical analysis. Two kinds of similarly constructed cigarettes with the same blend were analysed: superslim (17 mm circumference) and king-size (24 mm circumference).

Synchronization among the sampled signals was achieved by mapping two probes (e.g., temperature/chemistry or temperature/pressure) at a time. The physical and chemical events were visualised and compared between the cigarettes and puffing regimes.

Results

A series of temperature, pressure, and chemical maps were obtained for the superslim and king-size cigarettes under ISO and HCI conditions. The pressure in the burning cigarette was higher in the superslim cigarette, and the temperature distribution differed between the two cigarette formats. As expected, temperatures and pressures were higher under HCI puffing than under ISO puffing for both cigarette formats. Thermochemical maps for e.g., benzene and nitric oxide formation were qualitatively similar between the superslim and king-size cigarettes. For other substances the distribution was markedly different.

Conclusion

The application of multi-probe in-situ chemical sampling is suitable to analyse highly dynamic combustion and pyrolysis processes occurring inside the two types of cigarettes. Ultimately, a direct comparison of cigarette circumferences on the complex combustion processes and formation of smoke constituents was achieved. [Beitr. Tabakforsch. Int. 29 (2020) 44–54]