Showing papers in "Contributions to Tobacco Research in 1975"

The Formation of the Oxides of Carbon by the Pyrolysis of Tobacco

Abstract: Abstract Flue-cured Virginia tobacco has been heated in nitrogen and nitrogen/oxygen mixtures under flow conditions, and the rate of formation of carbon monoxide and carbon dioxide has been determined as a function of temperature, heating rate, and proportion of oxygen in the gas. When the tobacco is heated in nitrogen at heating rates comparable to those in a smouldering cigarette, 27 % of the carbon content of the tobacco is converted to carbon oxides. Both carbon oxides show two distinct formation regions: a low-temperature region (about 100°-450°C), and a high-temperature region (about 550°-900°C). These temperature limits are almost identical to those predicted from studies on the combustion coal of a cigarette burning in air. When tobacco, or the carbonaceous residue remaining after the pyrolysis experiments, is heated in nitrogen / oxygen mixtures, the total amount of carbon converted to carbon monoxide and carbon dioxide is independent of heating rate, but the relative proportions of the two oxides are strongly dependent on heating rate. At the lower heating rate, proportionally less carbon monoxide, and more carbon dioxide, is produced. Under oxidation conditions, about 70 % of both carbon oxides formed in the low-temperature region (100°-450°C) are produced by tobacco decomposition reactions, whereas in the high-temperature region about 10-20 % of the carbon monoxide, and 2-9 % of the carbon dioxide, are produced by tobacco decomposition.

Contributions to the Draw Resistance of a Burning Cigarette

Abstract: Abstract The draw resistance of a cigarette increases by about 50-60 % when the cigarette is lit, and the total draw resistance of the burning cigarette varies in a distinct manner as it is smoked. This effect is not normally due to an inherent increase in the impedance of the coal, because the effect disappears when the cigarette is extinguished. Rather, the effect is due to the heating of the gases flowing through the coal and down the tobacco rod, in particular (a) the increase in gas viscosity with temperature, (b) the increase in volumetric gas flow due to thermal expansion, and (c) the increase in the impedance of the unburnt tobacco rod, due to the deposition of smoke condensate on the rod. A hot-gas model, using the above contributing factors together with the known gas-phase temperature distribution inside the burning cigarette, can predict quantitatively (within the limits of experimental error) the observed variations of the draw resistance of a burning cigarette.

Selective Removal of Semivolatile Components of Cigarette Smoke by Various Filters

Abstract: Abstract The semivolatile portion of cigarette smoke contains acidic, basic, and neutral compounds that are important to the flavour and in some cases the physiological effects of smoke. A rapid method that could be used routinely for the gas chromatographic analysis of this portion of smoke was developed. A 160 mm glass capillary column was used to resolve approximately 150 semivolatile smoke components. Gas chromatography - mass spectrometry was used to identify about 35 of these components. Twenty known semivolatile compounds with different functional groups and boiling points were used to determine the effects of various filters on their removal from smoke. Standard cellulose acetate filters, cellulose acetate filters with glycerin, cellulose acetate filters with PEG 600, and cellulose acetate filters with activated carbon were evaluated. The cellulose acetate filters with glycerin and PEG 600 were more selective for the removal of aromatic hydrocarbons than were the standard cellulose acetate filters. The cellulose acetate filters with activated carbon were more selective for the removaI of the low-boiling semivolatile compounds than were the other filters tested.

The Effect of the Natural Sugar Content of Tobacco Upon the Acetaldehyde Concentration found in Cigarette Smoke

Abstract: Abstract All the evidence obtained in our laboratories has shown that the total aldehyde yield in tobacco smoke is not related to either sugar content or the equilibrium moisture content of the tobaccos. There is, however, a relationship between particulate matter [PM(WNF)]+ and aldehyde delivery. This accounts for some 41 % of the total variation between different cigarettes. + PM(WMF) = Total particulate matter - (water + nicotine)

Some Effects of Adding Sugar to Tobacco

Abstract: Abstract A series of cigarettes made from Burley tobacco containing different levels of added reducing sugar (10.5 to 17.8 %) have been examined. Compared to the control cigarette there was virtually no change in the deliveries of aldehydes and carbonyl constituents. However, an increase in the delivery of 2-furfural was observed, especially when fructose was the added sugar: even so, the conversion efficiency was only 1-2 %. A similar increase in the delivery of 2-furfural was also observed when glucose was added to flue-cured tobacco. An additional finding was that the addition of glucose and fructose reduced the delivery of nicotine. Radioactivity balance experiments on flue-cured cigarettes with added glucose indicated that this was probably due to an increase in the nicotine filtration efficiency of the cigarette rod. Filtration studies using air-cured cigarettes demonstrated that, on addition of glucose, there was a significant increase in the nicotine filtration efficiency of the tobacco rod and that less of the available nicotine was directed into the mainstream.

One-Dimensional Gas Concentration Profiles Within a Burning Cigarette During a Puff

Abstract: Abstract A technique for axial concentration measurements of several gas phase components of cigarette smoke during a two-second puff has been described. Gas concentration profiles constructed from these measurements were used to determine the axial order of the reactions which determine these concentrations. A one-dimensional model combustion reaction profile and a one-dimensional model coal temperature profile were presented. The diffusivities of several combustion gases through cigarette paper were calculated from the concentration data using the Owens-Reynolds model for the isothermal diffusion of gases through cigarette paper.

A Thirty-Port Smoking Machine for Continuous Smoke Generation

Abstract: Abstract Experience gained from a recent evaluation of smoking machines has been applied in the design of a sophisticated automatic smoking machine. Utilizing a reverse puff mechanism, a continuous or intermittent smoke stream is generated, diluted to selected concentration levels and channelled to multiple exposure apparatus. AlI functions are completely controlled by digital electronics as is the detection of faults in the system. Analysis of the smoke produced indicates that it is not chemically different from the smoke delivered by other types of apparatus

Chromatographic Determination of Hydrocarbon Waxes in Tobacco Leaf and Smoke

Abstract: Abstract Paraffins of tobacco Ieaf were separated by column chromatography on silicic acid. Leaf paraffins were fractionated from other wax constituents by chromatography in a definite sample to substrate to solvent ratio. The developed method was used to evaluate the transfer of paraffins and neophytadiene from leaf to smoke in a reference cigarette. Gas chromatographic separations were performed on a high-temperature liquid phase. Gas chromatography in conjunction with mass spectrometry was used to determine the paraffin composition of a representative flue-cured tobacco, a reference cigarette tobacco, and smoke condensate. It was concluded that paraffins were probably transferred to smoke relatively unchanged, while neophytadiene underwent some pyrolytic decomposition.

The Thermal Degradation of Tobacco: VI. Influence of Extraction on the Formation of Some Major Gas Phase Constituents

Abstract: Abstract Formation profiles have been determined for the major gas phase constituents formed in an inert atmosphere during the dynamic thermal decomposition of tobaccos extracted with hexane, chloroform, acetone, acetonitrile, and methanol. The profiles include methane, ethane, ethene, propane, propene, isoprene, formaldehyde, acetaldehyde, acetone, 2-butanone, acetonitrile, benzene, and toluene. Except for propene and propane, extraction of tobacco does not dramatically influence either the temperatures for maximum formation or the level of hydrocarbons formed during thermal decomposition of the tobaccos. This suggests that the majority of the gas phase hydrocarbons are formed from the insoluble leaf constituents. Isoprene has formation maxima at 375°C and 450°C, and extraction of tobacco with non-polar solvents removes leaf precursors responsible for the formation maxima at 375°C. Polar solvents remove the major isoprene precursors which are responsible for the maxima at 375° and 450°C. Extraction effects an increase of both formaldehyde and acetaldehyde formation but has little influence on the formation of either acetone or 2-butanone. The formation profile for acetonitrile has been established and shows that it has maximum formation at 410° and 500°C. Extraction has no influence either on the formation of benzene or toluene. Data from the profiles of these volatile constituents generally agree with smoke data from extracted tobacco which indicates that this method is useful for studying factors that influence the formation of the gas phase constituents

The Distribution with Respect to Smoke Particle Size of Dotriacontane, Hexadecane and Decachlorobiphenyl Added to Cigarettes

Abstract: Abstract When studying the distribution of smoke deposited in the lung, it is necessary to use a tracer which indicates the levels of particulate matter deposited at various sites. Because the site of deposition can be dependent on the particle size of the aerosol, it is important that the tracer should be uniformly distributed with respect to particle size, otherwise the levels of particulate matter may be wrongly estimated. The distributions in the smoke from a cigarette containing flue-cured tobacco of three possible tracers (dotriacontane, hexadecane and decachlorobiphenyl) have been measured; alI three show a slight dependence but probably not sufficient to exclude them from possible use in inhalation studies. However, because of the different environment which exists in the lung, and the possible dependence of the results on the type of tobacco, it should not be assumed that there are no selective effects

Phytosterols in Tobacco: Quantitative Analysis and Fate in Tobacco Combustion

Abstract: Abstract The influence of tobacco phytosterols (cholesterol, campesterol, stigmasteroI, b-sitosterol) on the chemical composition and biologicaI activity of tobacco smoke has been of concern to tobacco chemists. Therefore, a relatively simple method, utilizing a 14C-internal standard, chromatography on Sephadex and gas-liquid chromatography, was developed for the quantitative analysis of the phytosterols; this method was applied to the tobacco and smoke (mainstream and sidestream) of cigarettes and cigars to determine the fate of the phytosterols in burning tobacco. About 20 % of the total phytosterol content of tobacco was shown to be transferred intact into the smoke; about 2 % was possibly converted into polynuclear aromatic hydrocarbons. Radioactive tracer and pyrolysis studies were used to determine the nature of the phytosterol degradation products found in the smoke.

Leaf Quality and Usability: Theoretical Model I

Abstract: Abstract A changing concept in recent years on the usability of tobacco leaf has introduced many problems that may, not fit the traditional requirements of leaf quality. Usability represents the state of being usable without adverse effects to consumers. Theoretical Model I with selected markers is proposed for the development of tobacco materials with emphasis on improving tobacco usability. This preliminary Model I is based on currently available data, and can be improved as new information becomes available. Plant scientists may use this model to develop leaf tobacco of improved usability either through breeding, selection, and culture, or by means of homogenized leaf curing and reconstitution

Thermal Decomposition of Tobacco: V. Influence of Temperature on the Formation of Carbon Monoxide and Carbon Dioxide

Abstract: Abstract The temperature-yield profiles of CO and CO2 have been obtained by the analysis of the effluent gas from the differential thermaI analysis (DTA) and pyrolysis gas chromatography (PGC) of tobacco. The CO profiles obtained from DTA show that CO is continuously generated from 140° to 950°C and has four temperatures for maximum formation: 240°, 310°, 450° and 690°C. These maxima correspond to those exhibited by the effluent gas detection (EGD) curve. AIl data show that the major portion of CO is formed above 650°C, even though the weight loss of tobacco at these temperatures is less than 10 %. The CO2 profile obtained from thermal analysis also corresponds to effluent gas detection curve and shows that the majority of CO2 is formed below 500°C. The profiles for CO2 from PGC indicate that the reduction of CO2 by carbon to form CO at temperatures above 600°C are not significant under these pyrolysis conditions. Analysis of the gas phase from the thermal analysis of extracted tobaccos shows that this method is a means for studying the influence of product modification on the formation of CO and CO2 especially at lower temperatures. The PGC of these modified tobaccos appears to be of little value for studying the effect of product modification on the formation of CO and CO2

Determination of Volatile N-Nitrosamines in the Vapour Phase of the Smoke from Various Tobacco Products

Abstract: Abstract Volatile N-nitrosamines were determined in the vapour phase of tobacco smoke after accumulation of Iarge vapour samples on to a cooled capillary GLC column. Detection was effected by computerized mass spectrometry and by a nitrogen-specific detector. Five different tobacco products were studied with mass spectrometry for the presence of eight individuaI nitrosamines. The result was negative thirty-nine times and positive only once. Initially, the detection Iimit for the individual nitrosamines was 2 ng per 20-55 mI vapour injection; during this study the effective detection limit was Iowered for some of the compounds by a further twofold to fivefold increase of the vapour volume analysed. The one nitroso compound identified positively and unambiguously was N-nitrosopiperidine in the smoke from the American blend cigarettes. It amounted to about 5.6 ng in the vapour phase of the smoke of one cigarette. The partition of nitrosamines between vapour phase and particulate phase is not known, but amounts of more than 1 µg of dimethylnitrosamine or nitrosopiperidine in the whole smoke of one cigarette as found by some authors, seem improbably high. It is shown in this paper that exclusive use of the alkali flame ionization detector for nitrosamine determinations would have led to false-positive results, especially for dimethylnitrosamine.

Parameters Affecting the Selective Filtration of Certain Tobacco Smoke Components

Abstract: Abstract The purpose of this investigation was to attain a better understanding of the selective removal of certain compounds from cigarette smoke by filters. A gas chromatographic method for the determination of selected semivolatile smoke compounds was developed. The method, which utilizes a 160 m glass capillary column, was used to determine the efficiency of filters for the removal of these selected semivolatile compounds. A correlation was found between the selective filtration of these compounds from cigarette smoke and their distribution coefficients [Kd = (g compound/g filter)/ (g compound/cm3 air)] between air and various filter materials. In addition, a correlation was found between the physicaI and chemical nature of certain smoke compounds and their selective filtration. Previous work indicated that if a compound is to be selectively removed from tobacco smoke by a filter, [1] a significant portion of that compound should be in the vapour state as it passes through the filter and [2] the compound should have an affinity for the filter material. The relative rate of vapourization (Rv) was used as a measure of 1., and the totaI solubility parameter (d) was taken as a measure of 2. Values for the vapourization rate were calculated from the product, vapour pressure (P), molecular weight (M), and diffusion coefficient (D), (Rv = kPMD1/2). The correlation of Rv and δ with the selectivity (Sx) of cellulose acetate filters for smoke compounds is described by Sx = b0 + b1δ + b2δ (1n Rv), where b0, b1, and b2 are constants. This equation may be used to predict the selective filtration of semivolatile compounds from cigarette smoke.

Some Agronomic Factors Affecting N-Dimethyl-nitrosamine Content in Cigarette Smoke

Abstract: Abstract ExperimentaI cigarettes from tobaccos varying in genotype, nitrogen nutrition, stalk position, suckering practice, and curing methods were used to examine the Ievels of N-dimethylnitrosamine (DMN) in smoke. Measurable amounts of DMN were found in all experimental samples, ranging from 1.7 to 115 ng per gram of tobacco burned. DMN content in smoke generally increased as rate of N fertilization increased. However, there were wide seasonal, cultural, and varietal effects. Burley-type tobacco produced a much higher level of DMN than the bright-type tobacco. DMN content in smoke was significantly and positively related to Ieaf total N, totaI alkaloids, nicotine, nornicotine, total volatile bases and nitrate N, but negatively related to reducing sugars. Reconstituted sheet tobaccos made with homogenized-leaf-curing samples produced much lower amounts of DMN than conventionally cured leaf. Additional information is needed to elucidate the primary leaf constituents that serve as precursors of DMN.

Multiple Capillary Pressure Drop Standards

Abstract: Abstract This paper describes a simple device, consisting of a collection of glass capillary tubes, which can be used as a stable, pressure insensitive standard for calibrating pressure drop machines. For air flowing through a single capillary tube of the proper dimensions to give a pressure drop similar to that of a filter rod, the Reynolds number is about 2000, the boundary between laminar and turbulent flow. Since turbulent flow gives pressure drops which vary with atmospheric pressure, it is desirable to reduce this quantity to a level where laminar flow is always present. This can be accomplished by distributing the flow among 10 parallel capillaries of very small diameter. The capillaries were formed by drawing pyrex tubing on a Hupe glass drawing machine to a finished internaI diameter of .44 mm. Ten Iengths of this capillary were mounted in 8 mm tubing and were encased in a clear resin. After polymerization of the resin, the composite rod was sawed into appropriate lengths and cleaned in an ultrasonic bath. Microscopic examination of the finished tubes showed that each capillary was a clean, smooth-walled tube with a sharp entrance and exit. Calculation of the Reynolds number for the composite capillary gave a value of 314, which is well within the Iaminar flow region. The agreement between measured pressure drops of these standards and those calculated using Poiseuille's Iaw with an entry and exit correction is excellent. Daily measurements of the pressure drop of these standard tubes for a period of a month were conducted, and the random variability was found to be 1 % or Iess. Measurements of the pressure drop of these tubes at various pressures and temperatures covering the range of normaI laboratory conditions also demonstrated a lack of significant variability. Fouling of the tubes from atmospheric dust was not found to be a significant factor

Comparison of Pyrolytic Products from Flue-Cured Tobacco Leaf and a Reconstituted Tobacco Sheet

Abstract: Abstract Pyrolytic products of commercial tobacco sheet, flue-cured tobacco leaf, and stems were compared. The yields of acids, bases, neutrals, and phenolics were determined. The neutrals were further characterized by chromatography in order to examine pyrolysis fractions corresponding to biologically active cigarette smoke fractions. Individual phenols, carboxylic acids, polynuclear aromatic hydrocarbons (PAH), and nicotine were determined for sheet and leaf pyrolyzate. Analyses of constituents of various pyrolyzate fractions indicated significantly lower amounts of phenols, PAH, and nicotine in sheet and stem pyrolyzates than in leaf pyrolyzates

Determination of Ethylene and lsoprene in the Gas Phase of Cigarette Smoke by Infra-red Spectroscopy

Abstract: Abstract An infra-red method was developed for the quantitative determination of ethylene and isoprene in the gas phase of cigarette smoke. The smoke was collected by smoking the cigarettes on a five-port syringe type smoking machine and transferring it to a gas cell positioned in a double-beam infra-red spectrophotometer for the duration of the analysis. The smoke transfer to the gas cell and its subsequent removal from the celI were accomplished by connecting the smoking machine to a vacuum pump through the automated solenoid valve unit which controlled the analysis system. In this manner any specific puff of interest could be analysed for the ethylene and isoprene concentrations by measuring the corrected absorbance of the 10.52 µm and 11.18 µm absorbance bands, respectively. TotaI deliveries of ethylene and isoprene per cigarette were obtained by adding the deliveries from the individual puffs. The puff-by-puff delivery profile also was obtainable at the same time. In addition filter efficiency for ethylene and isoprene removaI may be determined by this method. The relative standard deviation at the two-sigma level was 3 % for ethylene and isoprene in the gas phase smoke from commercial cellulose acetate filter cigarettes. The analysis of a particular puff of smoke required only 75 seconds insuring the analysis of a relatively fresh smoke with good reproducibility and accuracy.

Genetic Influence on Chemical Constituents of Tobacco Leaf and Smoke

Abstract: Abstract Investigations have shown that many chemical constituents in tobacco (Nicotiana tabacum L.) plants and in the cured leaf are influenced by genetic, environmental, and cultural factors. The genetic basis for nicotine synthesis is well documented and plant breeders are capable of developing cultivars with varying levels. Differences for chemical constituents have been detected among cultivars and breeding lines which are attributed to genetic factors. Some of these constituents are: reducing sugars, polyphenols, phytosterols, and nitrogenous compounds. Research also indicates that alkalinity of water-soluble ash and certain smoke constituents are influenced by genetic factors

Analysis of Volatile Pyrolytic Products of Tobacco Constituents: Stearic Acid Pyrolysis

Abstract: Abstract A procedure has been developed to collect, transfer, and analyse volatile organic pyrolysis products of tobacco leaf compounds. The volatiles were collected in a series of three traps on adsorbents that also served as substrates for transfer and for introduction of the volatiles into a gas chromatograph. Analytical procedures are described for three gas chromatographic columns packed, respectively, with the three different adsorbents used in the traps. With this system, volatile pyrolyzates were collected and analysed without the use of cryogenic traps, vacuum manifolds, or gas-sampling valves. The applicability of the procedures is demonstrated for the pyrolysis volatiles of stearic acid, a tobacco constituent

Residue Levels of Fatty Compounds and Surfactants as Suckering Agents on Tobacco

Abstract: Abstract Fatty compounds including lauryI alcohol and methyl laurate and Tween 20 surfactant (polyoxyethylene [20] sorbitan monolaurate) and Tween 80 surfactant (polyoxyethylene [20] sorbitan monooleate) with 14C-labelling at various positions were used as suckering agents for Maryland, Burley, and bright tobacco types (Nicotiana tabacum L.) and their residues on the tobacco determined. An average residue of 1.61 ppm of fatty compounds and 1.0 ppm of surfactants were found. The combined totaI of 2.6 ppm residue due to these suckering agents is far below an earlier preliminary test of 4.8 ppm of residue in comparison with 7.000 ppm naturally occurring fatty compounds in tobacco.

Evaluations of Cigarettes Made with Mold-Damaged and Nondamaged Flue-cured Tobacco

Abstract: Abstract FIue-cured tobacco damaged by species of Aspergillus from commerciaI and experimental sources was shredded and made into cigarettes. Paired samples of nondamaged tobaccos served as controls. Subsamples of cigarettes were analysed for viable fungal propagules/g, 39 organic and inorganic compounds in the smoke and smoke condensates, and taste preference. PrincipaI fungi associated with leaves and shreds of mold-damaged tobacco were Aspergillus repens, A. ruber, and A. niger. Except for the originaI differences in the nicotine content and in the tar, there were no significant differences in total particulate matter nor in the amount of specific vapour phase components measured in the smoke from cigarettes made with mold-damaged and nondamaged tobaccos. Smoke panelists distinguished between cigarettes made with mold-damaged and nondamaged tobaccos and preferred cigarettes made with the latter. Viable fungus spores passed through the tobacco cylinder from lighted and nonlighted cigarettes. These data suggest the use of mold-damaged tobacco in cigarette manufacturing is to be avoided because of off-flavours and because the fungi isolated are common allergens to the respiratory tract of humans

Fractionation of Cigarette Smoke Condensate for Biological Testing: Concentration of Polynuclear Aromatic Hydrocarbon and Weak-Acid Fractions

Abstract: Abstract Cigarette smoke condensate (CSC) was fractionated for bioassay to determine possible tumorigenic activity on mouse skin. Two fractions which previously had shown activity were further separated. A weak-acid fraction (F 8) was separated into three subfractions. A polynuclear aromatic hydrocarboncontaining fraction (F 20) was divided into two fractions by gel permeation chromatography. The polynuclear aromatic hydrocarbons, the suspected active materials in F 20, were successfully concentrated into a fraction (F 55) representing only 0.05 % of CSC. These materials are currently undergoing bioassay.

Homogenized Leaf Curing: I. TheoreticaI Basis and Some Preliminary Results

Abstract: Abstract A new procedure (HLC) of curing tobacco leaf through homogenization, incubation, and dehydration is described. At the homogenate stage, chemicaI composition can be improved by controlled enzyme action, by extraction, or with chemical additives. PhysicaI properties can be improved by reconstitution. Preliminary results show HLC may provide smoke with quality comparable to that from conventionally cured material, but with relatively lower biologicaI response. There is a great potential in using the HLC procedure for labour saving as well as for improving leaf usability.

A Smoking Machine Attachment for the Analysis of Carbon Monoxide, Carbon Dioxide and Nitric Oxide in the Vapour Phase of Cigarette Smoke

Abstract: Abstract An eight-channel smoking attachment for the collection of the vapour phase from cigarettes has been developed. The utilisation of the device for the simultaneous puff by puff measurement of carbon monoxide, carbon dioxide and nitric oxide is described. The attachment has been constructed for use with the CSM 300 smoking machine but could readily be adapted for use with other smoking machines.

The Antioxidant Activity of Tobacco Smoke

Abstract: Abstract Cigarette smoke has been shown to contain free radicals in both the vapour and particulate phases. The present investigation was undertaken to find out whether these radicals could initiate or promote the formation of radical peroxides which might in turn lead to lipid peroxidation. To investigate this, a system involving the coupled oxidation of b-carotene and linoleic acid was utilized. In this coupled reaction, b-carotene is destroyed through oxidation by free peroxy radicals. The system can therefore be used as a convenient detector of auto-oxidative mechanisms in which peroxide radicals participate, as well as provide an assay for antioxidants, since in their presence oxidative destruction of b-carotene is blocked. Our results show that smoke did not contribute to the oxidative destruction of b-carotene but rather behaved as an antioxidant. Both smoke vapour and particulate matter were found to be highly antioxidant. A number of pure vapour phase components were tested and the bulk of antioxidant activity was found to be due to HCN. Smoke condensates from different tobacco types were compared and differentiated according to their relative efficiencies of antioxidant activities. For comparison, units of antioxidant activity were expressed as rate of change of optical density with time. The highest antioxidant activities were obtained with air-, flue-cured (cut) and perique tobaccos. Pipe tobacco had the least activity while cigar and flue-cured (granulated), stem and sheet tobaccos had intermediate values. Tests done on smoke fractions derived from the fractionation of total condensate revealed that antioxidant activity resided largely in the neutral and water-insoluble acid fractions with virtually no activity in the basic fractions. The mode of antioxidant action of tobacco smoke is discussed in terms of free-radical mechanisms.

Gamma Radiation Effects on Cigarettes

Abstract: Abstract Smoke from gamma irradiated 1R1 Reference cigarettes was compared to smoke from the non-irradiated cigarettes. Total particulate matter, nicotine, and tar levels decreased with increasing radiation dose. Nicotine was determined by gas chromatography, using 7-methyl- quinoline as an internal standard. Yields of solvent partition fractions of the smoke condensate and of chromatographic fractions of the condensate neutrals did not indicate significant changes in smoke composition resulting from gamma irradiation of the precursor cigarette tobacco. The composition of refined polycyclic aromatic hydrocarbon (PAH) fractions of smoke from irradiated cigarettes appeared to be identical to that of standard cigarettes. The expected decrease in PAH did not occur. It was concluded that gamma irradiation of cigarettes had no major effects on smoke composition.