Gas Phase Nicotine Research Articles

Effects of freebase/protonated nicotine concentration, liquid composition and electrical power on throat hit in direct-to-lung vaping: theory and clinical measurements

BackgroundFor decades, the tobacco industry has engineered the sensory characteristics of combustible tobacco products including the degree of harshness experienced at the back of the throat. Commonly referred to as...

Volatilization and partitioning of residual electronic cigarette emissions to particulate matter

The growing prevalence of electronic cigarettes (e-cigs) prompts investigation of their impact on indoor air quality. While the investigation of residual cigarette smoke, also known as third-hand smoke (THS), has been increasing, there is minimal literature on similar residue from e-cig emissions. Lab generated ammonium sulfate aerosol was introduced into a stainless-steel chamber which previously contained JUUL electronic cigarette vape. Aerosol composition was monitored using a high-resolution aerosol mass spectrometer. This was performed in the same chamber 3 times over 5 days. Species from electronic cigarette residue (nicotine and vegetable glycerin) were found to partition to particles with decreasing concentration over the multiple experiments while maintaining a consistent chemical signature. This signature matches closely to that of the primary electronic cigarette vape with notable exclusions of propylene glycol, benzoic acid, and cadmium. Electronic cigarette vape can deposit onto surfaces and act as a long-term source of gas phase nicotine which can concentrate on aerosols and increase human exposure. The chemical processing of vape residue observed here is less substantial than has been previously presented for residual cigarette smoke. While our experiments were performed under controlled conditions, they highlight the importance of understanding indoor electronic cigarette use and unintended routes of exposure.Copyright © 2023 American Association for Aerosol Research

Emission and Gas/Particle Partitioning Characteristics of Nicotine in Aerosols for Electronic Cigarettes.

Nicotine is a dependence-producing component in electronic cigarettes. The nicotine release characteristics of electronic cigarettes are closely connected with human exposure and respiratory health. In this paper, a theoretical model was established to study the effects of the compositions of e-liquids and the heating powers of device on the emission and gas/particle partitioning characteristics of nicotine in aerosols at equilibrium. The simulation results of nicotine emissions were compared with the experimental data. The errors between them were within a reasonable range. At a larger heating power level, a higher nicotine yield and a larger vaporization amount of e-liquids could be observed. Under the same heating power condition, a higher vegetable glycerin content in e-liquids could result in a lower nicotine emission. When the heating powers supplied by the device increased, a larger mass fraction of particle-phase nicotine in aerosols at equilibrium would appear. As more propylene glycol was added into e-liquids, a lower mass fraction of gas-phase nicotine would exist in aerosols at equilibrium. The results may provide more information for the industry to set technical standards for electronic cigarettes and for the government department to make regulatory policies.

Determination of 4-(Methylnitrosamino)-1-(3-Pyridyl)-1-Butanone (NNK) arising from tobacco smoke in airborne particulate matter

The most important tobacco-specific nitrosamine found in cigarette smoke and formed in ageing smoke after cigarettes are extinguished is 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). It is formed from nitrosation of nicotine, under particular conditions both in indoor and outdoor environments. NNK has been classified as a potent lung carcinogen which is expected to be found primarily in the particle-phase and to be stable in particulate matter. In this study tests have been carried out to show that a bisulfate-treated filter is more efficient than an untreated filter to collect both nicotine and NNK, and that the latter is stable in outdoor particulate matter. To characterize NNK in the outdoor environment, airborne samples were collected from 11 cities in USA, UK, Hong Kong and Malta with characteristics varying from low to high population densities and from urban to suburban to rural, and with desert characteristics and distinct climates. It has been shown that airborne particle + gas phase nicotine and particle-phase NNK behave in a linearly correlated manner. A seasonal analysis was carried out on a subset of data available from five sites in California, where the load of NNK in PM10 is driven by long range transport of the air masses passing over densely populated cities. In the winter season, the load of NNK in PM is higher than in summer in a statistically significant manner. The contamination of PM with NNK shows variability, but is observed at all sites. This paper highlights the potential risk of chronic exposure to NNK in particulate matter by the inhalation pathway.

Effect of temperature and humidity on the gas–particle partitioning of nicotine in mainstream cigarette smoke: A diffusion denuder study

During cigarette smoking, nicotine deposition in the mouth, upper airways and deep lung can occur via rapid diffusion of gas-phase nicotine and via deposition of particle-bound nicotine, with changing proportions, dependent on physical and chemical equilibria. We have used a diffusion denuder approach to physical equilibria to evaluate comprehensively the percentage of nicotine that is initially in the gas phase of mainstream cigarette smoke under different temperature (T) and relative humidity (RH) conditions. Smoking experiments with University of Kentucky 3R4F research cigarettes were performed at six denuder T values (291–335K) and three RH values (30%, 45% and 60%). G/P partitioning of nicotine increased significantly with increasing T, and decreased substantially with increasing RH. The measured gas diffusion coefficient of nicotine in the system, D298K = 0.071 ± 0.006cm2s−1, was consistent with published data. Application of the theoretical denuder model of Lipowicz and Piadè indicated that the initial gas-phase fraction (fgLP) of nicotine entering the denuder tube ranged from ≈ 0.012% to 7.2% depending on T and RH. The fgLP values were used to derive the G/P partitioning constant, Kp, proposed by Pankow, ranging from 1.61e-06 to 1.06e-03. The first reported use of van’t Hoff plots of Kp yielded an enthalpy change of 110kJmol−1, consistent with the thermodynamics of the solution process and the acid–base equilibrium of nicotine in droplets of mainstream smoke. These new data offer scope for improved modelling of nicotine behaviour in tobacco smoke and its subsequent deposition in the respiratory tract.

Low-energy electron-induced dissociation in gas-phase nicotine, pyridine, and methyl-pyrrolidine.

Dissociative electron attachment to nicotine, pyridine, and N-methyl-pyrrolidine was studied in the gas phase in order to assess their stability with respect to low-energy electron interactions. Anion yield curves for different products at electron energies ranging from zero to 15 eV were measured, and the molecular fragmentation pathways were proposed. Nicotine does not form a stable parent anion or a dehydrogenated anion, contrary to other biological systems. However, we have observed complex dissociation pathways involving fragmentation at the pyrrolidine side accompanied by isomerization mechanisms. Combining structure optimization and enthalpy calculations, performed with the Gaussian09 package, with the comparison with a deuterium-labeled N-methyl-d3-pyrrolidine allowed for the determination of the fragmentation pathways. In contrast to nicotine and N-methylpyrrolidine, the dominant pathway in dissociative electron attachment to pyridine is the loss of hydrogen, leading to the formation of an [M-H]- anion. The presented results provide important new information about the stability of nicotine and its constituent parts and contribute to a better understanding of the fragmentation mechanisms and their effects on the biological environment.

Isomers and Conformational Barriers of Gas-Phase Nicotine, Nornicotine, and Their Protonated Forms

We report extensive conformational searches of the gas-phase neutral nicotine, nornicotine, and their protonated analogs and the pathways and barriers for the interconversion between their various isomers that are based on ab initio second-order Møller-Plesset perturbation (MP2) electronic structure calculations. Initial searches were performed with the 6-31G(d,p), and the energetics of the most important structures were further refined from geometry optimizations with the larger aug-cc-pVTZ basis set. On the basis of the calculated free energies at T = 298 K for the gas-phase molecules, neutral nicotine has two dominant trans conformers, whereas neutral nornicotine is a mixture of several conformers. For nicotine, the protonation on both the pyridine and the pyrrolidine sites is energetically competitive, whereas nornicotine prefers protonation on the pyridine nitrogen. The protonated form of nicotine is mainly a mixture of two pyridine-protonated trans conformers and two pyrrolidine-protonated trans conformers, whereas the protonated form of nornicotine is a mixture of four pyridine-protonated trans conformers. Nornicotine is conformationally more flexible than nicotine; however, it is less protonated at the biologically important pyrrolidine nitrogen site. The lowest energy isomers for each case were found to interconvert via low (<6 kcal/mol) rotational barriers around the pyridine-pyrrolidine bond. These barriers are much lower than previous estimates based on lower levels of theory obtained without relaxation of the structure along the path. Nicotine was found to bind more strongly to tryptophan (Trp) than nornicotine, a finding that is consistent with nicotine's enhanced affinity in the nicotinic acetylcholide receptor.

Tobacco smoke aging in the presence of ozone: A room-sized chamber study

a b s t r a c t Exposure to tobacco pollutants that linger indoors after smoking has taken place ( thirdhand smoke , THS ) can occur over extended periods and is modulated by chemical processes involving atmospheric reactive species. This study investigates the role of ozone and indoor surfaces in chemical transformations of tobacco smoke residues. Gas and particle constituents of secondhand smoke (SHS) as well as sorbed SHS on chamber internal walls and model materials (cotton, paper, and gypsum wallboard) were charac- terized during aging. After smoldering 10 cigarettes in a 24-m 3 room size chamber, gas-phase nicotine was rapidly removed by sorption to chamber surfaces, and subsequently re-emitted during ventilation with clean air to a level of w10% that during the smoking phase. During chamber ventilation in the presence of ozone (180 ppb), ozone decayed at a rate of 5.6 h ! 1 and coincided with a factor of 5 less nicotine sorbed to wallboard. In the presence of ozone, no gas phase nicotine was detected as a result of re-emission, and higher concentrations of nicotine oxidation products were observed than when ventilation was performed with ozone-free air. Analysis of the model surfaces showed that heteroge- neous nicotine-ozone reaction was faster on paper than cotton, and both were faster than on wallboard. However, wallboard played a dominant role in ozone-initiated reaction in the chamber due to its large total geometric surface area and sink potential compared to the other substrates. This study is the first to show in a room-sized environmental chamber that the heterogeneous ozone chemistry of sorbed nicotine generates THS constituents of concern, as observed previously in bench-top studies. In addition to the main oxidation products (cotinine, myosmine and N-methyl formamide), nicotine-1-oxide was detected for the first time.

Sorption, desorption, and surface oxidative fate of nicotine

Nicotine dynamics in an indoor environment can be greatly affected by building parameters (e.g. relative humidity (RH), air exchange rate (AER), and presence of ozone), as well as surface parameters (e.g. surface area (SA) and polarity). To better understand the indoor fate of nicotine, these parameter effects on its sorption, desorption, and oxidation rates were investigated on model indoor surfaces that included fabrics, wallboard paper, and wood materials. Nicotine sorption under dry conditions was enhanced by higher SA and higher polarity of the substrate. Interestingly, nicotine sorption to cotton and nylon was facilitated by increased RH, while sorption to polyester was hindered by it. Desorption was affected by RH, AER, and surface type. Heterogeneous nicotine-ozone reaction was investigated by Fourier transform infrared spectrometry with attenuated total reflection (FTIR-ATR), and revealed a pseudo first-order surface reaction rate of 0.035 +/- 0.015 min(-1) (at [O(3)] = 6 +/- 0.3 x 10(15) molecules cm(-3)) that was partially inhibited at high RH. Extrapolation to a lower ozone level ([O(3)] = 42 ppb) showed oxidation on the order of 10(-5) min(-1) corresponding to a half-life of 1 week. In addition, similar surface products were identified in dry and high RH using gas chromatography-mass spectrometry (GC-MS). However, FTIR analysis revealed different product spectra for these conditions, suggesting additional unidentified products and association with surface water. Knowing the indoor fate of condensed and gas phase nicotine and its oxidation products will provide a better understanding of nicotine's impact on personal exposures as well as overall indoor air quality.

Effect of Ozone on Nicotine Desorption from Model Surfaces: Evidence for Heterogeneous Chemistry

Assessment of secondhand tobacco smoke exposure using nicotine as a tracer or biomarker is affected by sorption of the alkaloid to indoor surfaces and by its long-term re-emission into the gas phase. However, surface chemical interactions of nicotine have not been sufficiently characterized. Here, the reaction of ozone with nicotine sorbed to Teflon and cotton surfaces was investigated in an environmental chamber by monitoring nicotine desorption over a week following equilibration in dry or humid air (approximately 0% or 65-70% RH, respectively). The Teflon and cotton surfaces had N2-BET surface areas of 0.19 and 1.17 m2 g(-1), and water mass uptakes (at 70% RH) of 0 and 7.1% respectively. Compared with dry air baseline levels in the absence of O3, gas-phase nicotine concentrations decreased by 2 orders of magnitude for Teflon after 50 h at 20-45 ppb O3, and by a factor of 10 for cotton after 100 h with 13-15 ppb O3. The ratios of pseudo first-order rate constants for surface reaction (r) to long-term desorption (k) were r/k = 3.5 and 2.0 for Teflon and cotton surfaces, respectively. These results show that surface oxidation was competitive with desorption. Hence, oxidative losses could significantly reduce long-term re-emissions of nicotine from indoor surfaces. Formaldehyde, N-methylformamide, nicotinaldehyde, and cotinine were identified as oxidation products, indicating that the pyrrolidinic N was the site of electrophilic attack by O3. The presence of water vapor had no effect on the nicotine-O3 reaction on Teflon surfaces. By contrast, nicotine desorption from cotton in humid air was unaffected by the presence of ozone. These observations are consistent with complete inhibition of ozone-nicotine surface reactions in an aqueous surface film present in cotton but not in Teflon surfaces.

Fast determination of nicotine and 3-ethenylpyridine in indoor environments

Different sampling and analysis techniques for the determination of gas-phase nicotine and 3-ethenylpyridine in environmental tobacco smoke are reported. Graphitized carbon traps, annular diffusion denuders, and nebulizer collectors have been used as sampling devices in combination with either thermal desorption or with water extraction. Capillary gas chromatography and ion-pair reversed-phase chromatography were applied to desorbed and liquid samples obtained in an intercomparison indoor study. The methods developed here show some advantages over existing methods in terms of analysis time, sensitivity and loading capacity.

Phase Distribution of Nicotine in Real Environments As Determined by Two Sampling Methods

In order to clarify earlier failure to collect nicotine in environmental tobacco smoke (ETS) on acid-treated filters downstream of a particle filter, samples were collected using two methods that could differentiate between particle- and gas-phase nicotine. Sampling with a device consisting of a particle filter followed by acid-treated filters showed that fresh ETS nicotine is collected as an apparent gas-phase component whereas nicotine in aged ETS, commonly encountered in the environment, is partly or completely adsorbed to the particle filter. The filter adsorption could be abolished with a pretreatment, making the filter basic. In contrast, sampling with acid-treated denuders followed by a particle filter showed that ETS nicotine to a large extent is collected by the denuders as a gas-phase component in agreement with other studies. All parts of a sampling device should be analyzed so that ETS nicotine concentrations are not underestimated, and gas-phase nicotine should be collected with acid-treated denuders upstream of the particle filter.

The chemical composition of environmental tobacco smoke III. Identification of conservative tracers of environmental tobacco smoke

Several components of environmental tobacco smoke (ETS) have been determined in experiments conducted in a 30 m 3 Teflon chamber. The effect of residence time in the chamber on the particle size distribution, mass of particles, gas-particle equilibria, and chemical composition of both the gas and particle phases of environmental tobacco smoke has been studied. Many organic compounds present in tobacco smoke condensate are not found in the particle phase in environmental tobacco smoke but are present in the gas phase. Concentrations of several nitrogen containing organic compounds, identified in the chamber experiments, have been determined in several indoor environments where environmental tobacco smoke was present. These compounds were not found in indoor environments where environmental tobacco smoke was not present. The studies in the indoor environments indicate that gas phase nicotine and myosmine are removed from indoor environments at a much faster rate than gas phase 3-ethenylpyridine or 2-ethenylpyridine or particle-phase nicotine or cotinine. Gas-phase 3-ethenylpyridine and particle-phase nicotine are proposed as tracers of environmental tobacco smoke.

Determination of gas phase nicotine and 3‐ethenylpyridine, and particulate phase nicotine in environmental tobacco smoke with a collection bed – capillary gas chromatography system

AbstractA combined sampling and analysis technique for the determination of gas phase nicotine and 3‐ethenylpyridine, and of particulate phase nicotine in environmental tobacco smoke with capillary gas chromatography is reported. The major advantage of the technique is that all of the collected particulate phase material is analyzed by thermal desorption of the collected material rather than by analysis of only a fraction of the sample extracted from the collection medium. A Teflon filter microtube is used to collect particulate phase nicotine. This microtube is follwed by a small Tenax sorbent bed to collect gas phase nicotine and 3‐ethenylpyridine. After sampling, the Teflon filter is transferred to a clean glass tube and the tube becomes an insert for a modified packed column injector port where the material collected on the filter is heat desorbed to a cold capillary tubing trap. Gas phase nicotine and 3‐ethenylpyridine are also transferred from the Tenax to the GC column by thermal desorption from the Tenax sorbent bed. Gas phase nicotine and 3‐ethenylpyridine, and particulate phase nicotine are each determined by GC analysis of the desorbed material. Nicotine and 3‐ethenylpyridine are quantitated by the use of external standards. This technique is straightforward and can be used for semi‐real time determination of both gas and particulate phase compounds in environmental tobacco smoke. The results obtained by this technique compare well with those obtained by sampling with annular diffusion denuders.

Monitoring of Environmental Tobacco Smoke Nicotine with a Sorbent Bed-Capillary Gas Chromatograph System

Abstract A sorbent bed-capillary gas chromatographic analytical method well suited to monitor environmental tobacco smoke nicotine in an environmental chamber or in indoor environments has been developed. The sampled air passes directly through a glass tube filled with Tenax after which the tube becomes an insert for a packed column injector port where the sample is heat-desorbed to a cold trap and transferred to a capillary GC column. Nicotine is quantitated by the use of an external standard. The results show that this method can meet the need of monitoring nicotine in an environmental tobacco smoke chamber and can be easily applied to do routine environment monitoring. The method was used to monitor the concentration of gas phase nicotine in environmental tobacco smoke in a 30m3 Teflon chamber. The concentration of nicotine was found to be constant with time with ordinary fluorescent room lighting. However, when a UV-light bank was turned on to simulate photochemical conditions, the concentration of nicotine decayed after a short initiation period.

Hand pyrometer with two scale ranges

Exposure to tobacco pollutants that linger indoors after smoking has taken place (thirdhand smoke, THS) can occur over extended periods and is modulated by chemical processes involving atmospheric reactive species. This study investigates the role of ozone and indoor surfaces in chemical transformations of tobacco smoke residues. Gas and particle constituents of secondhand smoke (SHS) as well as sorbed SHS on chamber internal walls and model materials (cotton, paper, and gypsum wallboard) were characterized during aging. After smoldering 10 cigarettes in a 24-m3 room size chamber, gas-phase nicotine was rapidly removed by sorption to chamber surfaces, and subsequently re-emitted during ventilation with clean air to a level of ∼10% that during the smoking phase. During chamber ventilation in the presence of ozone (180 ppb), ozone decayed at a rate of 5.6 h−1 and coincided with a factor of 5 less nicotine sorbed to wallboard. In the presence of ozone, no gas phase nicotine was detected as a result of re-emission, and higher concentrations of nicotine oxidation products were observed than when ventilation was performed with ozone-free air. Analysis of the model surfaces showed that heterogeneous nicotine-ozone reaction was faster on paper than cotton, and both were faster than on wallboard. However, wallboard played a dominant role in ozone-initiated reaction in the chamber due to its large total geometric surface area and sink potential compared to the other substrates. This study is the first to show in a room-sized environmental chamber that the heterogeneous ozone chemistry of sorbed nicotine generates THS constituents of concern, as observed previously in bench-top studies. In addition to the main oxidation products (cotinine, myosmine and N-methyl formamide), nicotine-1-oxide was detected for the first time.