BackgroundThe attempt to understand the kinetic behavior of nicotine in tobacco will provide a basis for unraveling its energetics in tobacco burning and the formation of free radicals considered harmful to the cigarette smoking community. To the best of our knowledge, the high temperature destruction kinetic characteristics of nicotine have not been investigated before; hence this study is necessary especially at a time addiction science and tobacco research in general is gaining intense attention.MethodsThe pyrolysis of tobacco under conditions simulating cigarette smoking in the temperature region 200–700 °C has been investigated for the evolution of nicotine and pyridine from two commercial cigarettes coded ES1 and SM1 using gas chromatography hyphenated to a mass selective detector (MSD). Moreover, a kinetic model on the thermal destruction of nicotine within a temperature window of 673 and 973 K is proposed using pseudo-first order reaction kinetics. A reaction time of 2.0 s was employed in line with the average puff time in cigarette smoking. Nonetheless, various reaction times were considered for the formation kinetics of nicotine.ResultsGC–MS results showed the amount of nicotine evolved decreased with increase in the puff time. This observation was remarkably consistent with UV–Vis data reported in this investigation. Generally, the temperature dependent rate constants for the destruction of nicotine were found to be s−1 and s−1 for ES1 and SM1 cigarettes respectively. In addition, the amount of nicotine evolved by ES1 cigarette was ~10 times more than the amount of nicotine released by SM1 cigarette.ConclusionThe suggested mechanistic model for the formation of pyridine from the thermal degradation of nicotine in tobacco has been found to be agreement with the kinetic model proposed in this investigation. Consequently, the concentration of radical intermediates of tobacco smoke such as pyridinyl radical can be determined indirectly from a set of integrated rate laws. This study has also shown that different cigarettes can yield varying amounts of nicotine and pyridine depending on the type of cigarette primarily because of potential different growing conditions and additives introduced during tobacco processing. The activation energy of nicotine articulated in this work is consistent with that reported in literature.Graphical abstractThe anatomy of tobacco cigarette and the major chemistry involved during combustion (pyrolysis, GC–MS analysis, and kinetic modeling) Electronic supplementary materialThe online version of this article (doi:10.1186/s13065-016-0206-8) contains supplementary material, which is available to authorized users.
BackgroundConsensus of opinion in literature regarding tobacco research has shown that cigarette smoke can cause irreparable damage to the genetic material, cell injury, and general respiratory landscape. The alkaloid family of tobacco has been implicated is a series of ailments including addiction, mental illnesses, psychological disorders, and cancer. Accordingly, this contribution describes the mechanistic degradation of major tobacco alkaloids including the widely studied nicotine and two other alkaloids which have received little attention in literature. The principal focus is to understand their energetics, their environmental fate, and the formation of intermediates considered harmful to tobacco consumers.MethodThe intermediate components believed to originate from tobacco alkaloids in mainstream cigarette smoke were determined using as gas-chromatography hyphenated to a mass spectrometer fitted with a mass selective detector (MSD) while the energetics of intermediates were conducted using the density functional theory framework (DFT/B3LYP) using the 6-31G basis set.ResultsThe density functional theory calculations conducted using B3LYP correlation function established that the scission of the phenyl C–C bond in nicotine and β-nicotyrine, and C–N phenyl bond in 3,5-dimethyl-1-phenylpyrazole were respectively 87.40, 118.24 and 121.38 kcal/mol. The major by-products from the thermal degradation of nicotine, β-nicotyrine and 3,5-dimethyl-1-phenylpyrazole during cigarette smoking are predicted theoretically to be pyridine, 3-methylpyridine, toluene, and benzene. This was found to be consistent with experimental data presented in this work.ConclusionClearly, the value of the bond dissociation energy was found to be dependent on the π–π interactions which plays a primary role in stabilizing the phenyl C–C in nicotine and β-nicotyrine and the phenyl C–N linkages in 3,5-dimethyl-1-phenylpyrazole. This investigation has elucidated the energetics for the formation of free radicals and intermediates considered detrimental to human health in cigarette smoking.Graphical abstractSome molecular alkaloids of tobacco the plantElectronic supplementary materialThe online version of this article (doi:10.1186/s13065-016-0189-5) contains supplementary material, which is available to authorized users.
Despite intense campaigns to minimize cigarette smoking owing to the socio-economic risks associated with it, cigarette smoking worldwide has continued to rise. This is a major concern to both public health authorities and medical practioners. This paper examines the Kenyan status on cigarette smoking through measurement of various parameters including mass media campaigns, taxation, level of education, nature of employment, and government legislation. Descriptive research design was employed because of its robust capability to give an in depth analysis of state of affairs as it exists in relation to cigarette smoking patterns in three Kenyan counties (Nakuru, Kisii and Migori). The study involved respondents above 18 years of age and was carried out between March and April 2018. Chi-square statistics was used to assess the association between various variables. It is clear from this study that most cigarette smokers had acquired high school education and above; representing 70% of the respondents. At 95% confidence limit, the p-value = 0.39 and confidence interval, CI = -1.965-4.156. Therefore, cigarette smoking is dependent on the level of education. The odd ratio (OR) of 3.10 indicates a strong association between smoking and the level of education. This study also revealed that majority of the respondents smoked between 6 and 10 cigarettes per day (36%). Besides, 50% of the target population admitted to being aware of the health hazards caused by cigarette smoking despite their continued smoking habits. This survey has demonstrated that most cigarette smokers are not only well educated but are aware of the dangers of cigarette smoking. Moreover, most respondents are addicted to cigarette smoking despite taxes imposed on tobacco products including cigarettes. This characteristic behaviour may be attributed to high unemployment rates in Kenya which this study has established as one of the major reasons for cigarette smoking.
Despite intense campaigns to minimize cigarette smoking owing to the socioeconomic risks associated with it, cigarette smoking worldwide has continued to rise. This is a major concern to both public health authorities and medical practioners. This paper examines the Kenyan status on cigarette smoking through measurement of various parameters including mass media campaigns, taxation, level of education, nature of employment, and government legislation. Descriptive research design was employed because of its robust capability to give an in depth analysis of state of affairs as it exists in relation to cigarette smoking patterns in three Kenyan counties (Nakuru, Kisii and Migori). The study involved respondents above 18 years of age and was carried out between March and April 2018. Chi-square statistics was used to assess the association between various variables. It is clear from this study that most cigarette smokers had acquired high school education and above; representing 70% of the respondents. At 95% confidence limit, the p-value = 0.39 and confidence interval, CI =-1.965-4.156. Therefore, cigarette smoking is dependent on the level of education. The odd ratio (OR) of 3.10 indicates a strong association between smoking and the level of education. This study also revealed that majority of the respondents smoked between 6 and 10 cigarettes per day (36%). Besides, 50% of the target population admitted to being aware of the health hazards caused by cigarette smoking despite their continued smoking habits. This survey has demonstrated that most cigarette smokers are not only well educated but are aware of the dangers of cigarette smoking. Moreover, most respondents are addicted to cigarette smoking despite taxes imposed on tobacco products including cigarettes. This characteristic behaviour may be attributed to high unemployment rates in Kenya which this study has established as one of the major reasons for cigarette smoking.
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