No abstract

The pyrolytic behaviour of (−)-(S)-nicotine in methanol was investigated using on-line pyrolysis GC/MS to establish whether racemization to the R(+) antipode occurs and to identify other products of pyrolysis. The conditions used included pyrolysing the sample for 15 seconds in an atmosphere of 9% oxygen in nitrogen (275ml/min total flow) across the temperature range of 200°C–1000°C. A chiral Cyclodex-B analytical column (30m × 0.25mm i.d. × 0.25 μm film thickness) was used to separate the enantiomers of nicotine, although the two enantiomer peaks were not baseline resolved. The results of the experiment shows that there is no increase in (+)-(R)-nicotine levels across a wide temperature range. This suggests that the elevated levels of (+)-R-nicotine observed in tobacco smoke (compared to tobacco leaf material) are not due to the pyrolytic auto-racemization of (−)-(S)-nicotine but are a result of more complex interactions between (−)-(S)-nicotine and other smoke components. The pyrolysis of isotopically labelled nicotine established that nicotine undergoes thermal decomposition to β-nicotyrine which in turn may decompose to other products. Chirality 2010. © 2009 Wiley-Liss, Inc.

SUMMARYThe analysis of spent filters from human-smoked (HS) cigarettes has been used to estimate cigarette yields for over three decades. Until recently, the whole filter was used for estimation; however a part-filter method has been shown to improve the accuracy of estimated HS yields. The partfilter method uses only the mouth-end portion of the filter, downstream of the ventilation holes, for analysis. In this portion, the filtration efficiency is relatively constant irrespective of typical puff flow rates of humans and also minimizes butt length effects (e.g. nicotine condensation) on filtration efficiency. Therefore, the estimations of HS cigarette yields are more robust to human smoking conditions than previous whole-filter methods. British American Tobacco has adopted this method to obtain better understanding of how smokers actually use their products in their everyday environment. This can give information to help understand approaches to harm reduction. Since adopting this method, modifications and quality control features have been added to improve the accuracy of the estimation. This paper will describe in detail the methodology currently in use, along with sources of error, storage studies, quality control, repeatability and reproducibility. [Beitr. Tabakforsch. Int. 23 (2009) 232-243]

The UV absorption and electronic circular dichroism (ECD) spectra of (R)- and (S)-nicotine and (S)-nornicotine in aqueous solution were measured to a significantly lower wavelength range than previously reported, allowing the identification of four previously unobserved electronic transitions. The ECD spectra of the two enantiomers of nicotine were equal in magnitude and opposite in sign, while the UV absorption spectra were coincidental. In line with previous observations, (S)-nicotine exhibited a negative cotton effect centered on 263 nm with vibronic structure (π–π1* transition) and a broad, positive ECD signal at around 240 nm associated with the n–π1* transition. As expected this band disappeared when the pyridyl aromatic moiety was protonated. Four further electronic transitions are reported between 215 and 180 nm; it is proposed the negative maxima around 206 nm is either an n–σ* transition or a charge transfer band resulting from the movement of charge from the pyrrolidyl N lone pair to the pyridyl π* orbital. The pyridyl π–π2* transition may be contained within the negative ECD signal envelope at around 200 nm. Another negative maximum at 188 nm is thought to be the pyridyl π–π3* transition, while the lowest wavelength end-absorption and positive ECD may be associated with the π–π4* transition. The UV absorption spectra of (S)-nornicotine was similar to that of (S)-nicotine in the range 280–220 nm and acidification of the aqueous solution enhanced the absorption. The ECD signals of (S)-nornicotine were considerably less intense compared to (S)-nicotine and declined further on acidification; in the far UV region the ECD spectra diverge considerably. Chirality 25:288–293, 2013. © 2013 Wiley Periodicals, Inc.

No abstract

Tobacco-specific N-nitrosamines (TSNA) have been suggested by some scientists to play an important role in tobacco smoke carcinogenesis. We have developed and validated an LC-MS/MS method for the determination of TSNA, notably N-nitrosoanabasine (NAB), N-nitrosoanatabine (NAT), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and N-nitrosonornicotine (NNN), extracted from smoked cigarette filter tips. Reporting limits of 0.44, 0.89, 0.91 and 0.91ng mL À1 for NAB, NAT, NNK and NNN respectively were achieved. The newly developed method may find application in the filter analysis methodology for estimating the mouth-level exposure to NAB, NAT, NNK and NNN for cigarette smokers. TSNA levels were determined in mainstream smoke collected on industry standard Cambridge Filter Pads following smoking on a smoking machine. TSNA yields were compared with TSNA levels extracted from cigarette filter tips. However, the observation of the progressive post-smoking accumulation of TSNA during ambient storage of smoked cigarette filter tips potentially compromises use of this technique as an estimate of mouth-level exposure. Storage of smoked cigarette filter tips at sub-ambient temperatures reduced substantially the post-smoking synthesis of TSNA. N-nitrosonornicotine (NNN)

SummaryThe thermo-oxidative decomposition of lovage (Levisticum officinale) and davana (Artemisia pallens) essential oils has been studied by pyrolysis-gas chromatography/mass spectrometry in 9% oxygen and 91% nitrogen atmosphere at 300 °C to simulate low-temperature tobacco heating conditions. Both lovage and davana oils contain numerous chemical substances; the main components of both oils are various oxygen-containing compounds. Isobenzofuranones are the most important constituents of lovage oil, and their relative intensity changed significantly during oxidative pyrolysis. (Z)-ligustilide underwent two kinds of decomposition reactions: an aromatization reaction resulting in the formation of butylidenephthalide and the scission of the lactone ring with the elimination of carbon dioxide or carbon monoxide. Davanone is the main component of davana oil, which did not decompose considerably during low-temperature oxidative pyrolysis. However, the relative yield of the second most intensive component, bicyclogermacrene, reduced markedly due to bond rearrangement reactions. Davana ether underwent oxidation reactions leading to the formation of various furanic compounds. The changes in the composition of both essential oils could be interpreted in terms of bond splitting, intramolecular rearrangement mechanisms and oxidation reactions of several constituents during low-temperature oxidative pyrolysis. The applied thermo-oxidative method was found to be suitable to study the stability of the essential oils and monitor the decomposition products under simulated tobacco heating conditions. In spite of the complicated composition of the essential oils, no evidence for interaction between the oil components was found. [Beitr. Tabakforsch. Int. 29 (2020) 27–43]

Summary Activated carbons are effective adsorbents for many volatile organic compounds and are used in cigarette filters to remove selected smoke toxicants. Polymer-derived carbon is more effective in removing many vapour phase toxicants found in cigarette smoke than coconut-shell-derived carbon. We compared mouth-level exposure to “tar”, nicotine and five vapour phase constituents (1,3- butadiene, benzene, toluene, isoprene, acrylonitrile) in two groups of Romanian smokers of 4-mg or 8-mg International Organization for Standardization (ISO) “tar” bands. Test cigarettes with 4 and 8 mg ISO “tar” were manufactured for the study with two target levels of polymer-derived carbon (30 mg and 56 mg), along with control cigarettes containing a target level of 56 mg of coconut-shell-derived carbon in both “tar” bands. No significant differences were found between mouth-level exposure to “tar” or nicotine yields obtained from control and test products (p > 0.05) in either ISO “tar” band. Mouth-level exposure to each of the five vapour phase constituents was significantly lower from the test products with polymer-derived carbon (p < 0.0001) than from control cigarettes with coconut-shell-derived carbon, by an average of 25% with 30 mg polymer-derived carbon and around 50% with 56 mg. [Beitr. Tabakforsch. Int. 27 (2016) 40-53]