Volume 3 (1966): Edition 9 (December 1966)

A smoking machine is described which is capable of smoking cigarettes in large quantities completely automatically. The machine was developed from the smoking machine of BAT type for 30 cigarettes. 30 cigarettes are smoked simultaneously and each puff is drawn from the cigarette individually. The following processes are automatic: the feeding of the cigarettes from a hopper into the smoking head, the lighting and the smoking of the cigarettes, the counting of puffs, the ejection of the butts after a determined number of puffs and the extinction of the butts. The control of these automatic processes is effected electrically. In the case of a deficiency of cigarettes in the hopper or when the operation of the machine is defective, the staff is alerted by means of an automatic control system. The smoke is condensed in a cold trap with a high capacity. The capacity of the trap is large enough to receive the smoke production of five days. The puff profile of the smoking machine is rectangular. The smoking machine can be used for plain cigarettes as well as for filter cigarettes. The length of the cigarettes to be smoked is unrestricted. Any number of puffs per cigarette can be chosen. The conditions of smoking correspond to the CORESTA standard. The dimensions of the machine are small enough to make the machine fit easily in every normal laboratory hood. 8 machines can be supervised by one person. This means that one experienced person could control the smoking of 8000-10 000 cigarettes a day. It is shown that the smoking to a constant number of puffs gives the same results as the smoking to a constant butt length, provided the number of puffs yields the required butt length.

Gas chromatographic analyses of normal and branched paraffin hydrocarbons of cigarette smoke condensate were performed with SE 52 coated glass capillary columns using a flame ionization detector and working in isotherm temperature and in linear programmed temperature. This investigation was extended to fractions containing unsaturated aliphatic hydrocarbons, by using in this case both an electron capture detector and a flame ionization detector. Some chromatograms are reported.

The smoke of cigarettes with high base content was examined for primary and secondary bases. As 4'-nitro-azobenzenecarboxamides- (4) (NABSA) the bases were separated by column and thin-layer chromatography and identified by melting points, R_F-values, IR-spectra, retention times, mass-spectra, and elemental analyses. 27 primary and secondary bases were isolated and 24 of them identified. For the first time n-propylamine, n-butylamine, iso-butylamine, iso-pentylamine, b-phenethylamine, methyl ethylamine, diethylamine, methyl-b-phenethylamine, 1,2,5,6-tetrahydropyridine, aniline, 3-methylaminopyridine, and dihydrometanicotine were detected in cigarette smoke. Earlier results about the presence of pyrrolidine, piperidine, and 2-methylpyrrolidine in smoke could be confirmed. Presumably methyl-n-butylamine and methyl-iso-butylamine are to be found in tobacco smoke. One further amine was not identified.

An examination of the volatile bases in different types of tobacco was carried out. Virginia and Oriental types of cigarette tobaccos and a typical Burley tobacco were examined qualitatively and a blend of black tobacco was also analysed quantitatively. Ethylamine, iso-butylamine, b-phenethylamine, dimethylamine, methylethylamine, methyl-n-propylamine, methyl-b-phenethylamine, and 1,2,5,6-tetrahydropyridine were identified in tobacco for the first time. Among the tobacco bases identified ammonia, methylamine, iso-pentylamine, pyrrolidine, and piperidine were already known. Ammonia is the main component of the volatile bases. As to quantity the minor alkaloids nornicotine and anabasine are followed by methylamine and pyrrolidine. The quantitative relations of the decarboxylated amino acids correspond to that of amino acids contained in tobacco hydrolysates.

Dimethyl sulfide has been isolated from cigarette smoke by a combination of adsorption and partition gas chromatographic techniques. Positive identification of dimethyl sulfide was obtained by infra-red spectrophotometry, mass spectrometry and gas chromatographic retention times. Both infra-red and mass spectra are presented and their most important features are discussed. Based on gas chromatographic measurements, a semiquantitative estimation of the amount of dimethyl sulfide in cigarette smoke is given. A list of the sulfur compounds identified up to now in cigarette smoke is presented as well as some discussion about their possible origin. After some evidence given on the importance of sulfur compounds on the flavour of several natural products and of some synthetic compositions, the question is raised as to the possible effect of these sulfur compounds on the overall flavour and aroma of cigarette smoke.

To investigate the ability of fibrous filters to remove volatile smoke components selectively, filters containing quantities of liquid additives on a fibrous substrate were prepared and tested. Using long filter tips, selective filtration of vapourous materials such as isoprene, acetaldehyde, methanol, acetone, and toluene was achieved. It was found that vapour transport to the filter surface and the sorption of vapours by the liquid coating were of great importance in the process. Diffusion of vapours into the substrate fibers was also found to be important, but was less effective in modifying the filtration properties.

The distribution between the vapour and particulate phases of 17 volatile constituents of tobacco smoke in the boiling point range 21°C to 111°C was examined by gas chromatography. Analyses of the vapour passing through ambient temperature traps, namely, electrostatic and Cambridge Filter were carried out and compared with the analyses of vapours recovered by heating from the condensate precipitated in these traps. The vapours passing through the traps were compared with the vapour composition of smoke from which the particulate matter had been allowed to settle by gravity. Results indicated that the retention pattern of the Cambridge Filter Unit and the electrostatic trap in this range were very similar and that their efficiencies towards the 17 constituents examined ranged from 0 % to 18 %. The indications are that the composition of the vapour passing either of these traps is closely similar to that of the vapour phase in the original aerosol.

The purpose of this study was to learn how cellulose pyrolysis was affected by changes in atmospheres, by varied pyrolysis temperatures, by the addition of inorganic materials, and by chemical modifications of the cellulose molecule. These studies have led to the hypothesis that cellulose can pyrolyse by two different modes to form B(a)P. Large quantities of B(a)P can be formed by high temperature (850°C) isothermal pyrolysis of cellulose via a very efficient gaseous reaction route. In this reaction the B(a)P yield decreased in the presence of iron, cobalt, and nickel while the yield increased with increasing temperatures and with the introduction of oxygen into the system. In contrast, graduated heating experiments demonstrated that B(a)P began to form at 450°C. This reaction was inefficient with respect to B(a)P yield and was unaffected by the presence of metals. The B(a)P precursors were hypothesized to be nonvolatile, being formed via a solid state decomposition of cellulose and involving the generation of free radicals. This reaction was inhibited by the presence of nitric oxide or salts generating nitric oxide. Additionally, oxidation of the cellulose molecule at the C6 position produced a decreased B(a)P yield.

Experiments were performed to define the contribution of the cellulose component in cigarette-filler to the organoleptic qualities of smoke. Pure cellulose shreds added to leaf tobacco gave the smoke a harsh quality readily detected by the smoker. Similar amounts of cellulose powder and tobacco dust, homogenized together and made into a film which was then used as cigarette filler, did not show the harshness effect even up to levels of 44 % added cellulose content in the mixture. Presoaking the cellulose paper in aqueous tobacco solubles also prevented the harshness in smoke observed from pure cellulose shreds. It was concluded that the intimate mixture of noncellulosic components with the cellulose in tobacco lamina and stems to a large extent modifies the burning of the cellulose component from that of pure cellulose paper. Chemical analyses showed that the manner of cellulose addition influenced appreciably the cigarette-smoke composition, thus accounting qualitatively for the organoleptic changes noted.