Pyrolysis, tobacco

Aromatic Hydrocarbons. These are the most toxic of the hydrocarbons and inhalation of the vapor can cause acute intoxication. Benzene is particularly toxic and long-term exposure can cause anemia and leukopenia, even with concentrations too low for detection by odor or simple instmments. The currendy acceptable average vapor concentration for benzene is no more than 1 ppm. PolycycHc aromatics are not sufftcientiy volatile to present a threat by inhalation (except from pyrolysis of tobacco), but it is known that certain industrial products, such as coal tar, are rich in polycycHc aromatics and continued exposure of human skin to these products results in cancer. 

Chopra NM, Campbell BS, Hurley JC. 1978. Systematic studies on the breakdown of endosulfan in tobacco smokes Isolation and identification of the degradation products from the pyrolysis of endosulfan I in a nitrogen atmosphere. J Agric Food Chem 26 255-258. 

The involvement of tobacco smoke carcinogens in the aetiology of lung cancer is conclusively established, but the role of specific chemical carcinogens as inducers of colorectal cancer is much less clear. Mutagenic pyrolysis products derived from cooked food have come under suspicion as possible... 

Although the pyrolysis of some classes of polysaccharide materials has been studied quite extensively in the food, petrol and tobacco industry, very little has been published specifically on polysaccharide binders (arabic gum, tragacanth gum, fruit tree gum, honey and starch). The pyrolysis of glucane based polymers, especially cellulose, has been studied in detail [6,55], highlighting how anhydrosugars and furan derivatives are the main pyrolysis products, together with one-, two- and three-carbon aldehydes and acids. 

M. J. Wornat, E. B. Ledesma, and N. D. Marsh, PolycycUc aromatic hydrocarbons from the pyrolysis of catechol (ordio-dihydroxybenzene), a model fuel representative of entities in tobacco, coal, and lignin, Fuel 80,1711-1726 (2001). 

Brunnemann, K. D., M. V. Djordjevic, R. Peng, and D. Hoffmann. Analysis and pyrolysis of some N-nitrosamino acids in tobacco and tobacco smoke. 

Environmental chemicals and pollutants are also capable of inducing P450 enzymes. As previously noted, exposure to benzo[a]pyrene and other polycyclic aromatic hydrocarbons, which are present in tobacco smoke, charcoal-broiled meat, and other organic pyrolysis products, is known to induce CYP1A enzymes and to alter the rates of drug metabolism. Other environmental chemicals known to induce specific P450s include the polychlorinated biphenyls (PCBs), which were once used widely in industry as insulating materials and plasticizers, and 2,3,7,8-tetrachlorodibenzo-p-dioxin (dioxin, TCDD), a trace byproduct of the chemical synthesis of the defoliant 2,4,5-T (see Chapter 56). 

Sekine, H. and Nakahara, Y., Abuse of smoking methamphetamine mixed with tobacco I. Inhalation efficiency and pyrolysis products of methamphetamine, 3. Forensic Sci., 32(5), 1271-1280, 1987. 

Because of inhalation of smoke, especially tobacco smoke, the lungs are the most likely sites of cancer from exposure to PAH compounds. However, these compounds are also found in foods cooked under direct exposure to pyrolysis conditions and are suspected of causing cancer in the alimentary canal. Extraordinarily high rates of esophageal cancer have been observed in Linxian, China, and may be attributable to PAHs from unvented cookstoves.13 In this study, the glucuronide conjugate of 1-hydroxypyrene was monitored as a biomarker of exposure to PAH compounds (Figure 13.11). 

As part of the answer lies in ability to describe the volatility of biomass tars, the work was primarly undertaken to get some insights into this area. Due to the very complex nature of pyrolysis tars, there are not suitable estimation methods available -experimental data are needed for further development of these techniques. The experimental data are needed to increase our understanding of this phenomenon. In this paper, we present results from tobacco, hemicellulose and lignin tars. 

Another possibility is to use glycosides of some fragrances to be liberated from tobacco products (by pyrolysis). Since the respective glycosides are not volatile this would limit loss of aroma during storage. 

Pyrolysis studies of the leaf of Nicotiana tabacum received significant interest due to its use in cigarette manufacturing. A variety of pyrolysis studies on this subject were reported [37-42], Some of these were oriented toward tobacco leaf characterization. Other studies were done to understand the origin of certain smoke components. Some... 

Tobacco leaf has a complicated chemical composition including a variety of polymers and small molecules. The small molecules from tobacco belong to numerous classes of compounds such as hydrocarbons, terpenes, alcohols, phenols, acids, aldehydes, ketones, quinones, esters, nitriles, sulfur compounds, carbohydrates, amino acids, alkaloids, sterols, isoprenoids [48], Amadori compounds, etc. Some of these compounds were studied by pyrolysis techniques. One example of pyrolytic study is that of cuticular wax of tobacco leaf (green and aged), which was studied by Py-GC/MS [49]. By pyrolysis, some portion of cuticular wax may remain undecomposed. The undecomposed waxes consist of eicosyl tetradecanoate, docosyl octadecanoate, etc. The molecules detected in the wax pyrolysates include hydrocarbons (Cz to C34 with a maximum of occurrence of iso-Czi, normal C31 and anti-iso-C32), alcohols (docosanol, eicosanol), acids (hexadecanoic, hexadecenoic, octadecanoic, etc ). The cuticular wax also contains terpenoids such as a- and p-8,13-duvatriene-1,3-diols. By pyrolysis, some of these compounds are not decomposed and others generate closely related products such as seco-cembranoids (5-isopropyl-8,12-dimethyl-3E,8E,12E,14-pentadecatrien-2-one, 3,7,13-trimethyl-10-isopropyl-2,6,11,13-tetradecatrien-1al) and manols. By pyrolysis, c/s-abienol, (12-Z)- -12,14-dien-8a-ol, generates mainly frans-neo-abienol. 

Other small molecules present in tobacco were also studied by pyrolysis. For example, the pyrolysis products of nicotine at 700° C generate [50] the compounds given in Table 16.2.4. 

The analysis of tobacco smoke is a subject of numerous studies [51-55], Both mainstream smoke and sidestream smoke are complex mixtures in which about 4000 compounds have been identified [55a], As indicated previously (see Section 3.5) smoke is more complex than tobacco pyrolysate, because besides pyrolysis, some other processes such as combustion, distillation, and aerosol formation occur during smoking. 

Numerous other pyrolysis studies were performed on tobacco. Many of them were reported at dedicated meetings such as Tobacco Chemists Research Conferences and are referenced in specialized reports [63]. However, because of the extremely large amount of information in this field, the subject cannot be properly included in this book. 

Two other types of element-specific detector for nitrogen currently in use coupled to SFCs are the nitrogen phosphorus detector (NPD) and the thermal energy analyzer (TEA). The NPD uses a hot, catalytically active solid surface immersed in a layer of dissociated H2 and O2 to form electronegative N and P ions which are detected on a nearby electrode [2]. NPD has been shown to have broad application in SFC, especially in the agrochemical industry [3]. The TEA, as described by Fine et al. [4], uses low-temperature pyrolysis, followed by ozone-induced chemiluminescence, for the detection of compounds containing NO2 groups. The TEA has been used for the determination of tobacco-specific nitrosamines and explosives [5]. Both of these detectors require spedlic standards of the analytes of interest for quantitation... 

When the major alkaloid in tobacco samples is nor-nicotine, the commonly used steam-distillation method and automated procedures result in poor estimates of nicotine and nornicotine. Rosa18 therefore developed a pyrolysis-gas chromatographic method, whereby pyrolysis was carried out with a Victoreen pyrolyzer fitted to the gas chromatograph. Nicotine is relatively volatile and readily released by pyrolysis, even at 100°C. Nornicotine, being less volatile, showed maximum release by pyrolysis at 300°C. The pyrolysis-gas chromatography was carried out with ca. 1 mg of tobacco. The results obtained with the method are presented in Figure 5.3. 

QUALITATIVE COMPARISON OF PYROLYSIS-GAS CHROMATOGRAPHY OF THREE TOBACCO CULTIVARS18... 

The pyrolysis-gas chromatography offers a reliable and rapid means of estimating nornicotine in tobacco without extraction. 

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