A High Throughput Method for Estimating Mouth-Level Intake of Mainstream Cigarette Smoke.

INTRODUCTION: We developed a high throughput method for estimating smoker's mainstream smoke intake on a per-cigarette basis by analyzing discarded cigarette butts. This new method utilizes ultraviolet/visible (UV-Vis) spectrophotometric analysis of isopropanol-soluble smoke particulate matter extracted from discarded cigarette filters. METHODS: When measured under a wide range of smoking conditions for a given brand variant, smoking machine delivery of nicotine, benzene, polycyclic aromatic hydrocarbons, and tobacco-specific nitrosamines can be related to the overall filter extract absorbance at 360 nm. Once this relationship has been established, UV-Vis analysis of a discarded cigarette filter butt gives a quantitative measure of a smoker's exposure to these analytes. RESULTS: The measured mainstream smoke constituents correlated closely (correlation coefficients from 0.9303 to 0.9941) with the filter extract absorbance. These high correlations held over a wide range of smoking conditions for 2R4F research cigarettes as well as popular domestic cigarette brands sold in the United States. CONCLUSIONS: This low cost, high throughput method is suitable for high volume analyses (hundreds of samples per day) because UV-Vis spectrophotometry, rather than mass spectrometry, is used for the cigarette filter butt analysis. This method provides a stable and noninvasive means for estimating mouth-level delivery of many mainstream smoke constituents. The ability to gauge the mouth-level intake of harmful chemicals and total mainstream smoke for cigarette smokers in a natural setting on a cigarette-by-cigarette basis can provide insights on factors contributing to morbidity and mortality from cigarette smoking, as well as insights on strategies related to smoking cessation.

Chemical analysis of Alaskan Iq'mik smokeless tobacco.

INTRODUCTION: Iq'mik, a form of smokeless tobacco (ST), is traditionally used by Cup'ik and Yup'ik Eskimo people of western Alaska. Iq'mik is sometimes incorrectly considered to be a healthier alternative to smoking because its ingredients are perceived as "natural." Our chemical characterization of iq'mik shows that iq'mik is not a safe alternative to smoking or other ST use. METHODS: We measured nicotine and pH levels of tobacco and ash used to prepare iq'mik. We also characterized levels of toxins which are known to be present in ST including tobacco-specific nitrosamines (TSNAs) and polycyclic aromatic hydrocarbons (PAHs) using chromatographic separations coupled with isotope dilution mass spectrometry. RESULTS: Nicotine content in the iq'mik tobacco was very high, ranging from 35 to 43 mg/g, with a mean of 39 mg/g. The pH of the iq'mik tobacco-ash mixture was 11, an extremely high level compared with most ST products. High levels of PAHs were seen in the fire-cured tobacco samples with a benzo[a]pyrene level of 87 ng/g. Average TSNA levels in the tobacco were 34, 2,700, and 340 ng/g for 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), N'-nitrosonornicotine (NNN), and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), respectively. CONCLUSIONS: Iq'mik contains high levels of the more easily absorbed unionized nicotine as well as known carcinogenic TSNAs and PAHs. The perception that iq'mik is less hazardous than other tobacco products due to the use of "natural" ingredients is not warranted. This chemical characterization of iq'mik gives a better understanding of the risk of possible adverse health effects of its use.

Exposure to and deposition of fine and ultrafine particles in smokers of menthol and nonmenthol cigarettes.

INTRODUCTION: Research on the deposition of mainstream smoke particulate in the respiratory tract of smokers is needed to understand how exposure may vary based on cigarette menthol content. METHODS: We conducted a nine-participant crossover study in which smokers were randomly assigned to cigarettes differing primarily in menthol content. Participants smoked the test cigarettes ad libitum for one week, provided spot urine samples, and then smoked four test cigarettes in a laboratory session; this was repeated for the other test cigarette in week two. Fine and ultrafine particulate matter in exhaled breath were characterized, and smoking behavior was monitored. Participant-specific mainstream smoke, generated using each participant's topography data, was characterized. During home smoking, participants collected their spent test cigarette butts for estimates of mouth-level exposures (MLE) to mainstream nicotine and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). RESULTS: Participant-specific mainstream smoke NNK was higher (39%) and daily MLE to NNK was also higher (52%) when participants smoked the menthol cigarette. Nicotine was not significantly different. Participants retained more ultrafine particulate (43%) and fine particulate benzo(a)pyrene (43%) when smoking the menthol cigarette. There were no significant differences in the levels of urinary biomarkers for nicotine, NNK, or pyrene. CONCLUSION: This study demonstrates the use of noninvasive real-time techniques to measure exposure differences between cigarettes differing primarily in menthol content. Differences between NNK exposure, ultrafine particle and benzo(a)pyrene deposition, and smoking behavior were observed. Additional research using these techniques with cigarettes that differ only in menthol content is required to unequivocally attribute the exposure differences to presence or absence of menthol.

Mutagenicity of 11 cigarette smoke condensates in two versions of the mouse lymphoma assay.

Cigarette smoke condensate (CSC) is genotoxic in nearly all assays in which it has been tested. In this study, we investigated the mutagenicity of 11 CSCs using the microwell and soft-agar versions of the mouse lymphoma assay (MLA). These CSCs were prepared from commercial or experimental cigarettes, 10 of them were produced using International Organisation for Standardisation (ISO) conditions and one CSC was generated using intense Massachusetts Department of Public Health (MDPH) conditions. In the presence of rat liver S9, the L5178Y/Tk(+/-) mouse lymphoma cells were treated with 11 CSCs at different concentrations (25-200 µg/ml) for 4 h. All CSCs resulted in dose-dependent increases of both cytotoxicity and mutagenicity in both versions of the MLA. The mutagenic potencies of the CSCs were calculated as mutant frequency per microgram CSC from the slope of the linear regression of the dose-response curves and showed no correlations with the tar yield of the cigarette or nicotine concentrations of the CSCs. Comparing two CSCs produced from the same commercial cigarettes using two different smoking conditions, the one generated under ISO conditions was more mutagenic than the other generated under intense conditions on a per microgram CSC basis. We also examined the loss of heterozygosity (LOH) at four microsatellite loci spanning the entire chromosome 11 for the mutants induced by 11 CSCs. The most common type of mutation observed was LOH with chromosome damage spanning less than ∼34 Mbp. These results indicate that the MLA identifies different genotoxic potencies among a variety of CSCs and that the results from both versions of the assay are comparable.

Semi-volatiles in mainstream smoke delivery from select charcoal-filtered cigarette brand variants.

BACKGROUND: It has been reported that charcoal added to cigarette filters selectively removes many of the more volatile chemicals, but it is not clear to what extent charcoal may reduce the delivery of important less volatile chemical constituents in mainstream cigarette smoke. METHODS: We analysed machine-derived mainstream smoke deliveries (under three smoking regimens) for variants of a charcoal-filtered cigarette commercially test-marketed in the USA, focusing on selected polycyclic aromatic hydrocarbons (PAHs), phenols and tobacco-specific nitrosamines (TSNAs). RESULTS: While charcoal-containing filters selectively removed lower molecular weight PAHs from mainstream smoke, they did not significantly remove the heavier and more toxic PAHs studied, such as benzo[a]pyrene, a known carcinogen. Likewise, charcoal-containing filters removed phenols and TSNAs from mainstream smoke to differing amounts depending on the compound, filter design and the smoking regimen. CONCLUSIONS: The addition of sufficient charcoal to cigarette filters is known to remove many volatile compounds and can potentially reduce deliveries of certain semi-volatile compounds under some machine smoking regimens. Less volatile compounds, with a significant portion in the particulate phase, are less available for selective filtration by charcoal-containing filters than the more volatile compounds that reside predominantly in the gas phase.

Divergence between strength indicators in packaging and cigarette engineering: a case study of Marlboro varieties in Australia and the USA.

OBJECTIVES: To investigate how the tobacco industry is adapting to regulatory action in accordance with provisions of the Framework Convention on Tobacco Control that targets misleading packaging and labelling. To relate the packaging and labelling of new cigarette varieties to their construction and performance. METHODS: The principal design features and tar, nicotine and carbon monoxide yields of the Marlboro 'brand family' in Australia were measured and compared with those of the US equivalents. RESULTS: Marlboro Red and Blue/Medium, could not be differentiated in preliminary tests in Australia, but were different in the USA. However, yield testing showed Marlboro Blue/Medium did not have lower tar and nicotine yields in either country, indeed being higher in Australia. CONCLUSIONS: Colour can be used to market cigarettes as 'milder', independently of ISO yields and 'Light'/'Mild' descriptors. Banning of 'Light' and 'Mild' brand descriptors may be inadequate to end belief in less harmful cigarettes so long as the tobacco industry remains free to engineer 'mildness' and to use colours, other descriptors and design features to characterise varieties it wants to market as 'milder'.

Cytotoxicity of eight cigarette smoke condensates in three test systems: comparisons between assays and condensates.

Cytotoxic properties of tobacco smoke are associated with chronic tobacco-related diseases. The cytotoxicity of tobacco smoke can be tested with short-term predictive assays. In this study, we compare eight mainstream cigarette smoke condensates (CSCs) from commercial and experimental cigarettes in three different cytotoxicity assays with unique and overlapping endpoints. The CSCs demonstrated cytotoxicity in all assays. In the multiple cytotoxicity endpoint (MCE) assay with TK-6 cells, the cigarette varieties that had the highest EC50s for reduced cell growth also showed a positive dose-response relationship for necrotic cells. In the IdMOC multiple cell-type co-culture (MCTCC) system, all CSCs reduced the viability of the cells. Low concentrations of some CSCs had a stimulatory effect in lung microvascular endothelial cells and small airway epithelial cells. In the neutral dye assay (NDA), except for a 100% flue-cured tobacco CSC, there was little consistency between CSCs producing morphological evidence of moderate or greater toxicity and the CSCs with the lowest EC50s in the MCE or MCTCC assays. Overall, cigarettes made with flue-cured tobacco were the most cytotoxic across the assays. When results were expressed on a per-mg of nicotine basis, lower tar cigarettes were the most cytotoxic in primary human respiratory cells.

Estimating smokers' mouth-level exposure to select mainstream smoke constituents from discarded cigarette filter butts.

INTRODUCTION: Standardized machine smoking measurements are poor predictors of exposure. We have refined a method using the solanesol deposited in discarded cigarette butts as a marker for estimating deliveries of mainstream smoke constituents. Developing a fast and accurate method for measuring solanesol in cigarette filters to assess tobacco smoke intake could provide a way to assess how people smoke under natural conditions. We have developed and validated a new, lower-cost, high-throughput method to measure the solanesol content in discarded cigarette filter butts and correlated these measurements with mainstream smoke deliveries of nicotine and tobacco-specific nitrosamines (TSNAs). METHODS: Cigarettes were machine smoked under a variety of conditions to cover a wide range of nicotine deliveries and solanesol levels in the spent cigarette filter. Following machine smoking, a 1-cm portion of filter material, measured from the mouth end, was removed from the cigarette butts for analysis. Although an isotopically labeled solanesol analog is currently not commercially available, we achieved excellent quantitative results using a structurally similar compound, geranylgeraniol, as an internal standard (IS). After spiking with IS and solvent extracted, solanesol extracts were then analyzed using liquid chromatography coupled with a single-quadrupole mass analyzer. Analysis was carried out using manual preparation as well as a high-throughput 48-well format using automated liquid handlers. RESULTS: Recoveries of solanesol from cigarette butts exceeded 95% with excellent precision and exhibited excellent linearity for both preparation methods. In addition, we show that the mouth-level exposure for both nicotine and TSNAs may be estimated by their relation to the solanesol retained in the cigarette filter. DISCUSSION: We believe that this method provides excellent versatility and throughput for the estimation of mouth-level exposure to a wide range of toxins in cigarette smoke under naturalistic conditions. In addition, this method allows a far more accurate measure of exposure both from a single cigarette as well as from daily smoking.

Genotoxicity of 10 cigarette smoke condensates in four test systems: comparisons between assays and condensates.

The particulate fraction of cigarette smoke, cigarette smoke condensate (CSC), is genotoxic in many short-term in vitro tests and is carcinogenic in rodents. However, no study has evaluated a series of CSCs prepared from a diverse set of cigarettes and produced with different smoking machine regimens in several short-term genotoxicity tests. Here we report on the genotoxicity of 10 CSCs prepared from commercial cigarettes that ranged from ultra-low tar per cigarette (< or =6.5 mg) to full flavor (>14.5 mg) as determined by the Federal Trade Commission (FTC) smoking regimen, a reference cigarette blended to be representative of a U.S. FTC-regimen low-tar cigarette, and experimental cigarettes constructed of single tobacco types. CSCs were tested in the presence of rat liver S9 in the Salmonella plate-incorporation assay using frameshift strains TA98 and YG1041; in micronucleus and comet assays in L5178Y/Tk(+/-) 7.3.2C mouse lymphoma cells, and in CHO-K(1) cells for chromosome aberrations. All 10 CSCs were mutagenic in both strains of Salmonella, and the rank order of their mutagenic potencies was similar. Their mutagenic potencies in Salmonella spanned 7-fold when expressed as rev/mug CSC but 158-fold when expressed as rev/mg nicotine; the range of genotoxic potencies of the CSCs in the other assays was similar regardless of how the data were expressed. All 10 CSCs induced micronuclei with a 3-fold range in their potency. All but one CSC induced DNA damage over a 20-fold range, and all but one CSC induced chromosome aberrations over a 4-fold range. There was no relation among the genotoxic potencies of the CSCs across the assays, and a qualitative advantage of the addition of the other assays to the Salmonella assay was not supported by our findings. Although consideration of nicotine levels may improve the relevance of the quantitative data obtained in the Salmonella and possibly comet assays, compensatory smoking habits and other factors may make the data from the assays used here have qualitative but not quantitative value in assessing risk of cigarette types and cigarette smoking to human health.

Determination of eugenol, anethole, and coumarin in the mainstream cigarette smoke of Indonesian clove cigarettes.

Indonesian clove cigarettes (kreteks), typically have the appearance of a conventional domestic cigarette. The unique aspects of kreteks are that in addition to tobacco they contain dried clove buds (15-40%, by wt.), and are flavored with a proprietary "sauce". Whereas the clove buds contribute to generating high levels of eugenol in the smoke, the "sauce" may also contribute other potentially harmful constituents in addition to those associated with tobacco use. We measured levels of eugenol, trans-anethole (anethole), and coumarin in smoke from 33 brands of clove-flavored cigarettes (filtered and unfiltered) from five kretek manufacturers. In order to provide information for evaluating the delivery of these compounds under standard smoking conditions, a quantification method was developed for their measurement in mainstream cigarette smoke. The method allowed collection of mainstream cigarette smoke particulate matter on a Cambridge filter pad, extraction with methanol, sampling by automated headspace solid-phase microextraction, and subsequent analysis using gas chromatography/mass spectrometry. The presence of these compounds was confirmed in the smoke of kreteks using mass spectral library matching, high-resolution mass spectrometry (+/-0.0002 amu), and agreement with a relative retention time index, and native standards. We found that when kreteks were smoked according to standardized machine smoke parameters as specified by the International Standards Organization, all 33 clove brands contained levels of eugenol ranging from 2,490 to 37,900 microg/cigarette (microg/cig). Anethole was detected in smoke from 13 brands at levels of 22.8-1,030 microg/cig, and coumarin was detected in 19 brands at levels ranging from 9.2 to 215 microg/cig. These detected levels are significantly higher than the levels found in commercial cigarette brands available in the United States.

Effects of 10 cigarette smoke condensates on primary human airway epithelial cells by comparative gene and cytokine expression studies.

Cigarettes vary in tobacco blend, filter ventilation, additives, and other physical and chemical properties, but little is known regarding potential differences in toxicity to a smoker's airway epithelia. We compared changes in gene expression and cytokine production in primary normal human bronchial epithelial cells following treatment for 18 h with cigarette smoke condensates (CSCs) prepared from five commercial and four research cigarettes, at doses of approximately 4 microg/ml nicotine. Nine of the CSCs were produced under a standard International Organization for Standardization smoking machine regimen and one was produced by a more intense smoking machine regimen. Isolated messenger RNA (mRNA) was analyzed by microarray hybridization, and media was analyzed for secreted cytokines and chemokines. Twenty-one genes were differentially expressed by at least 9 of the 10 CSCs by more than twofold, including genes encoding detoxifying and antioxidant proteins. Cytochrome P450, family 1, subfamily A, polypeptide 1 (CYP1A1) and NAD(P)H dehydrogenase, quinone 1 (NQO-1) were selected for validation with quantitative real-time PCR (qRT-PCR) and Western blot analyses. NQO-1 expression determined with microarrays, qRT-PCR, and Western blotting differed among the CSC types, with good correlation among the different assays. CYP1A1 mRNA levels varied substantially, but there was little correlation with the protein levels. For each CSC, the three most induced and three most repressed genes were identified. These genes may be useful as markers of exposure to that particular cigarette type. Furthermore, differences in interleukin-8 secretion were observed. These studies lay the foundation for future investigations to analyze differences in the responses of in vivo systems to tobacco products marketed with claims of reduced exposure or reduced harm.

Effect of differing levels of tobacco-specific nitrosamines in cigarette smoke on the levels of biomarkers in smokers.

BACKGROUND: Smokers are exposed to significant doses of carcinogens, including tobacco-specific nitrosamines (TSNA). Previous studies have shown significant global differences in the levels of TSNAs in cigarette smoke because of the variation in tobacco blending and curing practices around the world. METHODS: Mouth-level exposure to 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) measured in cigarette butts and urinary concentrations of its major metabolite 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) were examined among 126 daily smokers in four countries over a 24-hour study period. RESULTS: As mouth-level exposure of NNK increased, the urinary NNAL increased even after adjustment for other covariates (beta = 0.46, P = 0.004). The relationship between mouth-level exposure to nicotine and its salivary metabolite, cotinine, was not statistically significant (beta = 0.29, P = 0.057), likely because of the very limited range of differences in mouth-level nicotine exposure in this population. CONCLUSIONS: We have shown a direct association between the 24-hour mouth-level exposure of NNK resulting from cigarette smoking and the concentration of its primary metabolite, NNAL, in the urine of smokers. Internal dose concentrations of urinary NNAL are significantly lower in smokers in countries that have lower TSNA levels in cigarettes such as Canada and Australia in contrast to countries that have high levels of these carcinogens in cigarettes, such as the United States. IMPACT: Lowering the levels of NNK in the mainstream smoke of cigarettes through the use of specific tobacco types and known curing practices can significantly affect the exposure of smokers to this known carcinogen.

Automated determination of seven phenolic compounds in mainstream tobacco smoke.

Exposure to hydroxyl-substituted arenes, commonly referred to as phenols or phenolic compounds, can have serious health consequences. Select phenols present in tobacco smoke are cardiovascular toxins, act as tumor co-promoters and show genotoxic activity. To examine the mainstream smoke levels of these compounds, we developed and applied a method for quantitative analysis of seven phenols (phenol, o-cresol, m-cresol, p-cresol, catechol, resorcinol, and hydroquinone) in mainstream smoke. Total mainstream smoke particulate matter was collected on a Cambridge filter pad and spiked with an isotopically labeled internal standard solution. This pad underwent an automated phenol derivatization procedure to increase analyte volatility and enhance detection. Following the derivatization step, phenols from the particulate matter were sampled using solid-phase microextraction with subsequent gas chromatography/mass spectrometric detection. Sensitivity, selectivity, accuracy, and reproducibility were more than adequate for routine detection of phenols in mainstream smoke. Detection limits ranged from 0.04-0.57 microg, with a quantification range of 0.1-710 microg. Higher sensitivity and sample throughput were achieved compared with previously described methods. Mainstream smoke from 28 brands of domestic commercial cigarettes was evaluated to assess typical levels, and reference cigarettes containing single tobacco blends were examined to ascertain the phenolic profile from different types of tobaccos. As expected under machine smoking conditions using the Federal Trade Commission parameters, full-flavored cigarettes deliver more phenols than the light varieties, followed by the ultra light varieties. Differences were seen in relative levels of phenolic compounds in the mainstream smoke from unfiltered cigarettes made with a single type of tobacco.

Analysis of volatile organic compounds in mainstream cigarette smoke.

Mainstream cigarette smoke is a complex aerosol containing more than 4400 chemicals. The proliferation of new brands has necessitated development of faster and more reliable methods capable of analyzing a wide range of compounds in cigarette smoke. Although the International Agency for Research on Cancer has classified whole cigarette smoke as a human carcinogen, many of the individual chemicals are themselves highly biologically active as carcinogens, teratogens, or have implications for cardiovascular disease. Among these chemicals are many volatile organic compounds (VOCs), e.g., benzene, ethylbenzene, and styrene. To analyze VOCs in mainstream cigarette smoke, we developed a novel headspace collection technique using polyvinylfluoride bags for sample collection followed by cannula transfer to evacuated standard 20-mL auto sampler vials. Coupling collection of the vapor-phase cigarette smoke with automated analysis by solid-phase microextraction and gas chromatography/mass spectrometry enabled us to routinely quantify selected VOCs in mainstream cigarette smoke. This technique has similar reproducibility to previous cold trap and impinger collection methods with significantly higher sample throughput and virtually no solvent waste. In this report we demonstrate the method's analytical capabilities by quantitatively analyzing 13 selected VOCs in mainstream cigarette smoke from top-selling domestic brands.

Determination of 14 polycyclic aromatic hydrocarbons in mainstream smoke from U.S. brand and non-U.S. brand cigarettes.

Tobacco smoke contains thousands of chemical compounds, including many carcinogenic polycyclic aromatic hydrocarbons (PAHs). To determine the concentration ranges of PAHs in tobacco smoke and to understand what factors alter their levels, we quantitatively measured 14 PAHs in mainstream smoke from a transnational U.S. brand (Marlboro) and from locally popular brand cigarettes from 14 countries. We used standardized machine smoking conditions (35-mL puff volume, 60-s puff interval, and 2-s puff duration), extraction of total particulate matter from the Cambridge filters, and gas chromatography/mass spectrometry detection. Deliveries of total PAHs in mainstream smoke of local brands were statistically significantly higher (p < 0.01) than Marlboros in seven countries. In four countries, Marlboro cigarettes had mainstream smoke total PAH levels that were statistically significantly higher (p < 0.01) than local brands. In the remaining three countries, the differences in PAH levels were not statistically significant. Under standard machine smoking conditions, PAH levels were negatively correlated with cigarette filter ventilation levels. We found that several local brands containing primarily flue-cured tobacco filler had relatively high mainstream smoke PAH deliveries, in agreement with findings by previous researchers that flue-cured tobacco typically delivers more PAHs than other tobacco types. We also observed that PAHs were inversely correlated with total carcinogenic tobacco-specific nitrosamines and nitrate content, but these correlations were not statistically significant at the 95% confidence interval. The findings suggest that tobacco blend and nitrate levels may influence PAH deliveries, but other factors may confound this relation.

Determination of tar, nicotine, and carbon monoxide yields in the smoke of bidi cigarettes.

A survey of the nicotine, tar, and carbon monoxide (CO) levels in mainstream smoke from 21 brands of bidi cigarettes and five brands of traditional cigarettes was conducted using a variation of the Federal Trade Commission (FTC) standardized cigarette smoking machine method. The primary difference between this method and the FTC method was a reduction of the 60-s puff interval to 15 s. The shorter puff interval was required to prevent the bidi cigarettes from self-extinguishing and may represent a closer approximation to human usage. The goal of this study was to evaluate the smoke-delivery potential for tar, nicotine, and CO in mainstream smoke from bidi cigarettes compared with traditional domestic cigarettes smoked under identical conditions. Approximately half of the bidi brands examined were marketed as filtered varieties. Unlike traditional cigarettes, the filtered and unfiltered bidi brands yielded comparable smoke deliveries. Thus, a filtered bidi cigarette brand does not provide any harm-reduction benefit that might result from a reduction in levels of tar, nicotine, and CO compared with an unfiltered variety. Our findings indicate that bidi cigarettes can deliver high levels of tar (77.9+/-9.5 mg/bidi), nicotine (2.7+/-.4 mg/bidi), and CO (39.2+/-5.7 mg/bidi). In comparison, traditional cigarettes smoked using the bidi cigarette protocol have lower tar and CO yields, but have nicotine deliveries comparable with bidi cigarettes.

Development of a method to assess cigarette smoke intake.

Tar and nicotine deliveries of cigarettes measured using current standardized smoking machine protocols provide poor estimates of smoke exposure. The characteristics of human smoking behavior vary considerably and differ from the rigid parameters used with current standardized smoking machine protocols. Current alternatives, including measurement of biomarkers, are invasive, time-dependent, and can be too expensive to be used as mechanisms for carrying out large-scale investigations required to help determine the influence of cigarette design on smoking behaviors. To obtain more reasonable estimates of mainstream smoke exposure, we developed a method to quantitatively measure solanesol, a naturally occurring component in tobacco that is deposited during smoking in the cigarette filter butt. Quantification of solanesol extracted from the filters using liquid chromatography and tandem mass spectrometry is efficient, rapid, and extremely reliable. We found that the amount of solanesol deposited in a cigarette filter is related to the mainstream smoke deliveries of tar and nicotine under a variety of smoking conditions. In addition, the amount of solanesol trapped in the filter remains stable at least 4 weeks after smoking. Measuring solanesol in cigarette filters as an exposure marker provides a noninvasive means to obtain reasonable estimates of mainstream tar and nicotine smoke deliveries under a wide variety of smoking conditions.