Rivista e Edizione

Volume 31 (2022): Edizione 2 (July 2022)

Volume 31 (2022): Edizione 1 (March 2022)

Volume 30 (2021): Edizione 4 (November 2021)

Volume 30 (2021): Edizione 3 (July 2021)

Volume 30 (2021): Edizione 2 (May 2021)

Volume 30 (2021): Edizione 1 (March 2021)

Volume 29 (2020): Edizione 3 (December 2020)

Volume 29 (2020): Edizione 2 (August 2020)

Volume 29 (2020): Edizione 1 (April 2020)

Volume 28 (2019): Edizione 7 (December 2019)

Volume 28 (2019): Edizione 6 (August 2019)

Volume 28 (2019): Edizione 5 (May 2019)

Volume 28 (2018): Edizione 4 (December 2018)

Volume 28 (2018): Edizione 3 (October 2018)

Volume 28 (2018): Edizione 2 (August 2018)

Volume 28 (2018): Edizione 1 (April 2018)

Volume 27 (2017): Edizione 8 (December 2017)

Volume 27 (2017): Edizione 7 (September 2017)

Volume 27 (2017): Edizione 6 (April 2017)

Volume 27 (2017): Edizione 5 (January 2017)

Volume 27 (2016): Edizione 4 (October 2016)

Volume 27 (2016): Edizione 3 (July 2016)

Volume 27 (2016): Edizione 2 (April 2016)

Volume 27 (2016): Edizione 1 (January 2016)

Volume 26 (2015): Edizione 7 (September 2015)

Volume 26 (2015): Edizione 6 (June 2015)

Volume 26 (2015): Edizione 5 (March 2015)

Volume 26 (2014): Edizione 4 (December 2014)

Volume 26 (2014): Edizione 3 (September 2014)

Volume 26 (2014): Edizione 2 (July 2014)

Volume 26 (2014): Edizione 1 (April 2014)

Volume 25 (2013): Edizione 8 (December 2013)

Volume 25 (2013): Edizione 7 (September 2013)

Volume 25 (2013): Edizione 6 (June 2013)

Volume 25 (2013): Edizione 5 (March 2013)

Volume 25 (2012): Edizione 4 (December 2012)

Volume 25 (2012): Edizione 3 (August 2012)

Volume 25 (2012): Edizione 2 (June 2012)

Volume 25 (2012): Edizione 1 (February 2012)

Volume 24 (2011): Edizione 6 (November 2011)

Volume 24 (2011): Edizione 5 (May 2011)

Volume 24 (2011): Edizione 4 (January 2011)

Volume 24 (2010): Edizione 3 (November 2010)

Volume 24 (2010): Edizione 2 (July 2010)

Volume 24 (2010): Edizione 1 (April 2010)

Volume 23 (2009): Edizione 6 (December 2009)

Volume 23 (2009): Edizione 5 (September 2009)

Volume 23 (2009): Edizione 4 (May 2009)

Volume 23 (2008): Edizione 3 (December 2008)

Volume 23 (2008): Edizione 2 (August 2008)

Volume 23 (2008): Edizione 1 (April 2008)

Volume 22 (2007): Edizione 5 (June 2007)

Volume 22 (2007): Edizione 4 (January 2007)

Volume 22 (2006): Edizione 3 (October 2006)

Volume 22 (2006): Edizione 2 (July 2006)

Volume 22 (2006): Edizione 1 (April 2006)

Volume 21 (2005): Edizione 8 (December 2005)

Volume 21 (2005): Edizione 7 (October 2005)

Volume 21 (2005): Edizione 6 (July 2005)

Volume 21 (2005): Edizione 5 (April 2005)

Volume 21 (2004): Edizione 4 (December 2004)

Volume 21 (2004): Edizione 3 (October 2004)

Volume 21 (2004): Edizione 2 (July 2004)

Volume 21 (2004): Edizione 1 (March 2004)

Volume 20 (2003): Edizione 8 (December 2003)

Volume 20 (2003): Edizione 7 (November 2003)

Volume 20 (2003): Edizione 6 (July 2003)

Volume 20 (2003): Edizione 5 (March 2003)

Volume 20 (2002): Edizione 4 (December 2002)

Volume 20 (2002): Edizione 3 (August 2002)

Volume 20 (2002): Edizione 2 (June 2002)

Volume 20 (2002): Edizione 1 (February 2002)

Volume 19 (2001): Edizione 7 (October 2001)

Volume 19 (2001): Edizione 6 (July 2001)

Volume 19 (2001): Edizione 5 (April 2001)

Volume 19 (2001): Edizione 4 (January 2001)

Volume 19 (2000): Edizione 3 (October 2000)

Volume 19 (2000): Edizione 2 (July 2000)

Volume 19 (2000): Edizione 1 (April 2000)

Volume 18 (1999): Edizione 6 (December 1999)

Volume 18 (1999): Edizione 5 (July 1999)

Volume 18 (1999): Edizione 4 (April 1999)

Volume 18 (1998): Edizione 3 (December 1998)

Volume 18 (1998): Edizione 2 (August 1998)

Volume 18 (1998): Edizione 1 (April 1998)

Volume 17 (1997): Edizione 3 (December 1997)

Volume 17 (1997): Edizione 2 (September 1997)

Volume 17 (1996): Edizione 1 (December 1996)

Volume 16 (1995): Edizione 4 (November 1995)

Volume 16 (1995): Edizione 3 (July 1995)

Volume 16 (1994): Edizione 2 (June 1994)

Volume 16 (1994): Edizione 1 (May 1994)

Volume 15 (1992): Edizione 3 (November 1992)

Volume 15 (1992): Edizione 2 (April 1992)

Volume 15 (1991): Edizione 1 (August 1991)

Volume 14 (1990): Edizione 6 (June 1990)

Volume 14 (1989): Edizione 5 (October 1989)

Volume 14 (1989): Edizione 4 (February 1989)

Volume 14 (1989): Edizione 3 (January 1989)

Volume 14 (1988): Edizione 2 (October 1988)

Volume 14 (1987): Edizione 1 (December 1987)

Volume 13 (1986): Edizione 5 (December 1986)

Volume 13 (1986): Edizione 4 (August 1986)

Volume 13 (1986): Edizione 3 (July 1986)

Volume 13 (1985): Edizione 2 (December 1985)

Volume 13 (1985): Edizione 1 (January 1985)

Volume 12 (1984): Edizione 5 (November 1984)

Volume 12 (1984): Edizione 4 (July 1984)

Volume 12 (1984): Edizione 3 (February 1984)

Volume 12 (1983): Edizione 2 (June 1983)

Volume 12 (1983): Edizione 1 (February 1983)

Volume 11 (1982): Edizione 5 (November 1982)

Volume 11 (1982): Edizione 4 (August 1982)

Volume 11 (1982): Edizione 3 (January 1982)

Volume 11 (1981): Edizione 2 (September 1981)

Volume 11 (1981): Edizione 1 (March 1981)

Volume 10 (1980): Edizione 3 (October 1980)

Volume 10 (1980): Edizione 2 (July 1980)

Volume 10 (1979): Edizione 1 (December 1979)

Volume 9 (1978): Edizione 5 (December 1978)

Volume 9 (1978): Edizione 4 (July 1978)

Volume 9 (1977): Edizione 3 (October 1977)

Volume 9 (1977): Edizione 2 (June 1977)

Volume 9 (1977): Edizione 1 (April 1977)

Volume 8 (1976): Edizione 7 (October 1976)

Volume 8 (1976): Edizione 6 (June 1976)

Volume 8 (1976): Edizione 5 (March 1976)

Volume 8 (1975): Edizione 4 (December 1975)

Volume 8 (1975): Edizione 3 (August 1975)

Volume 8 (1975): Edizione 2 (May 1975)

Volume 8 (1975): Edizione 1 (January 1975)

Volume 7 (1974): Edizione 5 (September 1974)

Volume 7 (1974): Edizione 4 (April 1974)

Volume 7 (1973): Edizione 3 (November 1973)

Volume 7 (1973): Edizione 2 (June 1973)

Volume 7 (1973): Edizione 1 (January 1973)

Volume 6 (1972): Edizione 5 (October 1972)

Volume 6 (1972): Edizione 4 (August 1972)

Volume 6 (1972): Edizione 3 (March 1972)

Volume 6 (1971): Edizione 2 (September 1971)

Volume 6 (1971): Edizione 1 (July 1971)

Volume 5 (1970): Edizione 6 (December 1970)

Volume 5 (1970): Edizione 5 (November 1970)

Volume 5 (1970): Edizione 4 (August 1970)

Volume 5 (1969): Edizione 3 (December 1969)

Volume 5 (1969): Edizione 2 (August 1969)

Volume 5 (1969): Edizione 1 (June 1969)

Volume 4 (1968): Edizione 7 (December 1968)

Volume 4 (1968): Edizione 6 (November 1968)

Volume 4 (1968): Edizione 5 (July 1968)

Volume 4 (1968): Edizione 4 (May 1968)

Volume 4 (1968): Edizione 3 (February 1968)

Volume 4 (1967): Edizione 2 (October 1967)

Volume 4 (1967): Edizione 1 (August 1967)

Volume 3 (1966): Edizione 9 (December 1966)

Volume 3 (1966): Edizione 8 (December 1966)

Volume 3 (1966): Edizione 7 (November 1966)

Volume 3 (1966): Edizione 6 (September 1966)

Volume 3 (1966): Edizione 5 (May 1966)

Volume 3 (1965): Edizione 4 (October 1965)

Volume 3 (1965): Edizione 3 (August 1965)

Volume 3 (1965): Edizione 2 (May 1965)

Volume 3 (1965): Edizione 1 (April 1965)

Volume 2 (1964): Edizione 7 (November 1964)

Volume 2 (1964): Edizione 6 (October 1964)

Volume 2 (1964): Edizione 5 (May 1964)

Volume 2 (1964): Edizione 4 (February 1964)

Volume 2 (1963): Edizione 3 (October 1963)

Volume 2 (1963): Edizione 2 (June 1963)

Volume 2 (1963): Edizione 1 (March 1963)

Volume 1 (1962): Edizione 10 (December 1962)

Volume 1 (1962): Edizione 9 (December 1962)

Volume 1 (1962): Edizione 8 (November 1962)

Volume 1 (1962): Edizione 7 (November 1962)

Volume 1 (1962): Edizione 6 (July 1962)

Volume 1 (1962): Edizione 5 (February 1962)

Volume 1 (1961): Edizione 4 (November 1961)

Volume 1 (1961): Edizione 3 (August 1961)

Volume 1 (1961): Edizione 2 (May 1961)

Volume 1 (1961): Edizione 1 (January 1961)

Dettagli della rivista
Formato
Rivista
eISSN
2719-9509
Pubblicato per la prima volta
01 Jan 1992
Periodo di pubblicazione
4 volte all'anno
Lingue
Inglese

Cerca

Volume 23 (2008): Edizione 1 (April 2008)

Dettagli della rivista
Formato
Rivista
eISSN
2719-9509
Pubblicato per la prima volta
01 Jan 1992
Periodo di pubblicazione
4 volte all'anno
Lingue
Inglese

Cerca

6 Articoli
Accesso libero

Determination of Environmental Tobacco Smoke from a Second-Generation Electrically Heated Cigarette Smoking System and Conventional Cigarettes

Pubblicato online: 30 Dec 2014
Pagine: 1 - 7

Astratto

Abstract

This substudy of a randomized, controlled, forced switching, open-label, parallel-group clinical study in a total of 100 healthy adult male and female smokers compared environmental tobacco smoke (ETS) produced from smoking a second generation electrically heated cigarette smoking system (EHCSS), two conventional cigarettes, and no-smoking. Concentrations of air constituents including respirable suspended particulate matter (RSP), carbon monoxide (CO), and total volatile organic compounds (TVOCs) and ETS markers including solanesol-related particulate matter (Sol-PM), ultraviolet absorbing particulate matter (UVPM), fluorescing particulate matter (FPM), nicotine and 3-ethenylpyridine (3-EP) were measured in a ventilated, furnished conference room over a period of 2 hours on separate occasions. Except for TVOCs, concentrations of air constituents and ETS markers were reduced by 40% to more than 90% when adult smokers were smoking the EHCSS as compared to smoking conventional cigarettes. CO and most ETS marker concentrations were in the same range as no-smoking.

Accesso libero

A Modelling Approach to Develop Machine Smoking Protocols Reflecting Human Puffing Behaviour for Conventional Cigarettes

Pubblicato online: 30 Dec 2014
Pagine: 8 - 18

Astratto

Abstract

Our objective was to develop machine-smoking protocols (i.e. puff volume, puff duration and puff frequency) reflecting the distribution of human smoking behaviour as a complement to the International Standard (ISO) protocol. For this purpose, a modelling approach based on smoking topography and excretion data of urinary nicotine metabolites from clinical studies in the UK and Japan was used.

Three smoking protocols (LOW, MEDIUM and HIGH) were based on the 10th percentile, the mean and the 90th percentile of the puff volumes obtained from topography data. The corresponding puff durations were estimated by linear regression analysis of the puff duration/puff volume relationship. Finally, puff frequency was estimated using a predictive model assuming that the nicotine yield is a linear function (i.e. proportional) to the amount of air actually drawn through the burning part of the cigarette. This approach was termed ‘nicotine proportion method‘ where the puff frequency is changed iteratively until it equals the corresponding nicotine uptake measured in human smokers during a clinical study. The assumption was verified by measuring the nicotine yield in the laboratory on three modelled protocols for four conventional cigarettes. In 10 out of 12 cases, a very good agreement was observed between the estimated nicotine yields obtained with our modelling approach and the measured nicotine yields obtained from smoking machines in the laboratory.

Although smoking virtually identical cigarettes, smoking protocols based on topography and excretion data of urinary nicotine metabolites from the UK clinical study were different than those based on data from the study performed in Japan. This may be explained by different smoking behaviour between these two populations of smokers.

Accesso libero

Formation of Tobacco Specific Nitrosamines in Mainstream Cigarette Smoke; Part 1, FTC Smoking

Pubblicato online: 30 Dec 2014
Pagine: 19 - 31

Astratto

Abstract

This report evaluates the formation of nitrosonornicotine (NNN) and of 4-(methyl-nitrosamino)-1-(3-pyridyl)-1-butanone (NNK) from nicotine, and of NNN from nornicotine in the mainstream smoke of a burning cigarette. The cigarettes analyzed in the study were Kentucky reference cigarettes 1R4F and 2R4F, and five other cigarettes, three of them having tobaccos with low levels of tobacco specific nitrosamines (TSNAs). All cigarettes had ‘tar’ levels around 10 mg [where ‘tar’ is defined as the weight of total wet particulate matter (TPM) minus the weight of nicotine and water]. Cigarettes were smoked according to the U.S. Federal Trade Commission (FTC) puffing regimen, using a 35 mL puff volume, 2 sec puff duration and 60 sec puff intervals. Three separate experiments were performed in this study to evaluate the proportion of TSNAs transferred from preexistent tobacco TSNAs and the proportion formed during smoking (pyrosynthesized). In one experiment, the results were obtained by GC/MS analysis of 13C3-TSNAs formed in smoke when 13C3-nicotine was intentionally added to cigarettes. Another experiment used GC analysis with chemiluminescence detection of TSNAs from smoke before and after an excess of nornicotine was intentionally added to cigarettes, and another experiment consisted of LC/MS/MS analysis of 2H4-TSNAs formed in the smoke when 2H4-nicotine and when 2H4-nornicotine were intentionally added to cigarettes. The use of different analytical methods for the study of TSNA formation conveyed an additional level of confidence regarding the reliability of the results obtained. It was found that NNK was generated during smoking from nicotine with 3 × 10-5% to 8 × 10-5% conversion (0.3 ppm to 0.8 ppm conversion of the nicotine) while the result for NNN generation was not conclusive. One experiment demonstrated the formation of NNN from nicotine between 4 × 10-5% and 1.5 × 10-4% (0.4 ppm to 1.5 ppm reported to nicotine), but another experiment did not provide proof of NNN formation, with a limit of quantitation LOQ for NNN corresponding to 5 × 10-5% (or 0.5 ppm). Nornicotine was proven to generate NNN, and the results for the 2R4F cigarette showed 3.3 × 10-3% yield (33 ppm reported to nornicotine) in one experiment and 4.6 × 10-3% (46 ppm reported to nornicotine) in a different experiment, the agreement being very good. Using the results from this study, it was concluded that pyrosynthesis may account for about 5% to 10% of the NNK in mainstream smoke for a filter cigarette with the FTC ‘tar’ level around 10 mg. Pyrosynthesis may account for higher proportions of smoke TSNAs when the cigarette tobacco is low in TSNAs, since the mainstream smoke TSNAs yield from direct transfer from tobacco is small in this case. The contribution of pyrosynthesis may account for 5% to 25% of NNN in mainstream cigarette smoke, or potentially an even higher proportion when the tobacco blend is both low in TSNAs and high in nornicotine. Anabasine is typically present at low levels in tobacco and therefore the formation of nitrosoanabasine(NAB) is of less interest. Anatabine is present in different tobaccos in a range similar to that of nornicotine and being a secondary amine has the potential to act similarly to nornicotine. However, the pyrosynthesis of nitrosoanatabine (NAT) from anatabine was not evaluated in the present study. The study indicated that complete elimination of TSNAs from tobacco is unlikely to completely eliminate the TSNAs from cigarette smoke, and that high nornicotine tobaccos should be avoided in order to minimize the levels of NNN in cigarette smoke.

Accesso libero

Isolation, Fractionation, and Identification of Sucrose Esters from Various Oriental Tobaccos Employing Supercritical Fluids

Pubblicato online: 30 Dec 2014
Pagine: 32 - 45

Astratto

Abstract

Isolation, fractionation, and identification of sucrose esters from aged oriental tobacco employing supercritical fluids have been completed. Underivatized sucrose ester-rich extracts were obtained using supercritical CO2 at densities greater than 0.73 g/mL. Lower density CO2 provided extracts with notable amounts of tobacco derived material; yet, no detectable sucrose ester content. Preparative supercritical fluid chromatography (SFC) provided for an additional purification of the sucrose ester-enriched fraction after column optimization. Structural assignments of the SFC fractions were facilitated using gas chromatography/mass spectrometry (GC/MS) accompanied by N, O-bis(trimethylsilyl)trifluoroacetamide-dimethylformamide (BSTFA-DMF) derivatization of the free hydroxyl groups and high performance-liquid chromatography/mass spectrometry (HPLC/MS). From a relative quantitative perspective regardless of tobacco type, sucrose esters having an acetyl group on C6 of the glucose function (Group III) were in higher concentration compared to both the concentration observed for sucrose ester of Group I (acetyl group on C3 of fructose) and sucrose ester of Group II (no acetyl group on either glucose or fructose). Saturated fatty acid constituents were found to range from a maximum total of 18 carbons to a minimum total of 13 carbons. Unsaturated and isomeric fatty acid homologues were detected within the Group II sucrose ester.

Accesso libero

Mathematical Modeling of a Lit-End Cigarette: Puffing Cycle and Effects of Puff Counts

Pubblicato online: 30 Dec 2014
Pagine: 46 - 62

Astratto

Abstract

The burning cycles of a lit-end cigarette were numerically simulated using a 3-D model that includes both the cigarette and its surrounding ambient air and the effects of buoyancy forces. The solid and gas phases were treated separately in a thermally non-equilibrium environment. The tobacco pyrolysis and char oxidation were modeled using multi-precursor models. The changes in tobacco column porosity and its subsequent effects on permeability and gas diffusivity were included. The mass, momentum, energy, and species transport equations were solved in a discretized computational domain using a commercially available computational fluid dynamics (CFD) code. The model was applied to puff a cigarette under different puffing intensities and the effects of puff volume, puff profile, and puff duration were studied. The results show that the model is capable of reproducing the major features of a burning cigarette during both smoldering and puffing. For the puffing and puff-by-puff cases, the solid and gas temperatures as well as those mainstream smoke constituents predicted by the model are in a good agreement with experimental results. A parametric study shows the significant effect of puff volume, puff profile, ventilation rate, and puff counts on solid and gas phase temperatures as well as gaseous species concentrations and mainstream smoke delivery. The buoyancy forces have shown to be very important in both smoldering and puffing.

Accesso libero

Letter to the Editor: Tobacco Research and Its Relevance to Science, Medicine and Industry

Pubblicato online: 30 Dec 2014
Pagine: 63 - 65

Astratto

6 Articoli
Accesso libero

Determination of Environmental Tobacco Smoke from a Second-Generation Electrically Heated Cigarette Smoking System and Conventional Cigarettes

Pubblicato online: 30 Dec 2014
Pagine: 1 - 7

Astratto

Abstract

This substudy of a randomized, controlled, forced switching, open-label, parallel-group clinical study in a total of 100 healthy adult male and female smokers compared environmental tobacco smoke (ETS) produced from smoking a second generation electrically heated cigarette smoking system (EHCSS), two conventional cigarettes, and no-smoking. Concentrations of air constituents including respirable suspended particulate matter (RSP), carbon monoxide (CO), and total volatile organic compounds (TVOCs) and ETS markers including solanesol-related particulate matter (Sol-PM), ultraviolet absorbing particulate matter (UVPM), fluorescing particulate matter (FPM), nicotine and 3-ethenylpyridine (3-EP) were measured in a ventilated, furnished conference room over a period of 2 hours on separate occasions. Except for TVOCs, concentrations of air constituents and ETS markers were reduced by 40% to more than 90% when adult smokers were smoking the EHCSS as compared to smoking conventional cigarettes. CO and most ETS marker concentrations were in the same range as no-smoking.

Accesso libero

A Modelling Approach to Develop Machine Smoking Protocols Reflecting Human Puffing Behaviour for Conventional Cigarettes

Pubblicato online: 30 Dec 2014
Pagine: 8 - 18

Astratto

Abstract

Our objective was to develop machine-smoking protocols (i.e. puff volume, puff duration and puff frequency) reflecting the distribution of human smoking behaviour as a complement to the International Standard (ISO) protocol. For this purpose, a modelling approach based on smoking topography and excretion data of urinary nicotine metabolites from clinical studies in the UK and Japan was used.

Three smoking protocols (LOW, MEDIUM and HIGH) were based on the 10th percentile, the mean and the 90th percentile of the puff volumes obtained from topography data. The corresponding puff durations were estimated by linear regression analysis of the puff duration/puff volume relationship. Finally, puff frequency was estimated using a predictive model assuming that the nicotine yield is a linear function (i.e. proportional) to the amount of air actually drawn through the burning part of the cigarette. This approach was termed ‘nicotine proportion method‘ where the puff frequency is changed iteratively until it equals the corresponding nicotine uptake measured in human smokers during a clinical study. The assumption was verified by measuring the nicotine yield in the laboratory on three modelled protocols for four conventional cigarettes. In 10 out of 12 cases, a very good agreement was observed between the estimated nicotine yields obtained with our modelling approach and the measured nicotine yields obtained from smoking machines in the laboratory.

Although smoking virtually identical cigarettes, smoking protocols based on topography and excretion data of urinary nicotine metabolites from the UK clinical study were different than those based on data from the study performed in Japan. This may be explained by different smoking behaviour between these two populations of smokers.

Accesso libero

Formation of Tobacco Specific Nitrosamines in Mainstream Cigarette Smoke; Part 1, FTC Smoking

Pubblicato online: 30 Dec 2014
Pagine: 19 - 31

Astratto

Abstract

This report evaluates the formation of nitrosonornicotine (NNN) and of 4-(methyl-nitrosamino)-1-(3-pyridyl)-1-butanone (NNK) from nicotine, and of NNN from nornicotine in the mainstream smoke of a burning cigarette. The cigarettes analyzed in the study were Kentucky reference cigarettes 1R4F and 2R4F, and five other cigarettes, three of them having tobaccos with low levels of tobacco specific nitrosamines (TSNAs). All cigarettes had ‘tar’ levels around 10 mg [where ‘tar’ is defined as the weight of total wet particulate matter (TPM) minus the weight of nicotine and water]. Cigarettes were smoked according to the U.S. Federal Trade Commission (FTC) puffing regimen, using a 35 mL puff volume, 2 sec puff duration and 60 sec puff intervals. Three separate experiments were performed in this study to evaluate the proportion of TSNAs transferred from preexistent tobacco TSNAs and the proportion formed during smoking (pyrosynthesized). In one experiment, the results were obtained by GC/MS analysis of 13C3-TSNAs formed in smoke when 13C3-nicotine was intentionally added to cigarettes. Another experiment used GC analysis with chemiluminescence detection of TSNAs from smoke before and after an excess of nornicotine was intentionally added to cigarettes, and another experiment consisted of LC/MS/MS analysis of 2H4-TSNAs formed in the smoke when 2H4-nicotine and when 2H4-nornicotine were intentionally added to cigarettes. The use of different analytical methods for the study of TSNA formation conveyed an additional level of confidence regarding the reliability of the results obtained. It was found that NNK was generated during smoking from nicotine with 3 × 10-5% to 8 × 10-5% conversion (0.3 ppm to 0.8 ppm conversion of the nicotine) while the result for NNN generation was not conclusive. One experiment demonstrated the formation of NNN from nicotine between 4 × 10-5% and 1.5 × 10-4% (0.4 ppm to 1.5 ppm reported to nicotine), but another experiment did not provide proof of NNN formation, with a limit of quantitation LOQ for NNN corresponding to 5 × 10-5% (or 0.5 ppm). Nornicotine was proven to generate NNN, and the results for the 2R4F cigarette showed 3.3 × 10-3% yield (33 ppm reported to nornicotine) in one experiment and 4.6 × 10-3% (46 ppm reported to nornicotine) in a different experiment, the agreement being very good. Using the results from this study, it was concluded that pyrosynthesis may account for about 5% to 10% of the NNK in mainstream smoke for a filter cigarette with the FTC ‘tar’ level around 10 mg. Pyrosynthesis may account for higher proportions of smoke TSNAs when the cigarette tobacco is low in TSNAs, since the mainstream smoke TSNAs yield from direct transfer from tobacco is small in this case. The contribution of pyrosynthesis may account for 5% to 25% of NNN in mainstream cigarette smoke, or potentially an even higher proportion when the tobacco blend is both low in TSNAs and high in nornicotine. Anabasine is typically present at low levels in tobacco and therefore the formation of nitrosoanabasine(NAB) is of less interest. Anatabine is present in different tobaccos in a range similar to that of nornicotine and being a secondary amine has the potential to act similarly to nornicotine. However, the pyrosynthesis of nitrosoanatabine (NAT) from anatabine was not evaluated in the present study. The study indicated that complete elimination of TSNAs from tobacco is unlikely to completely eliminate the TSNAs from cigarette smoke, and that high nornicotine tobaccos should be avoided in order to minimize the levels of NNN in cigarette smoke.

Accesso libero

Isolation, Fractionation, and Identification of Sucrose Esters from Various Oriental Tobaccos Employing Supercritical Fluids

Pubblicato online: 30 Dec 2014
Pagine: 32 - 45

Astratto

Abstract

Isolation, fractionation, and identification of sucrose esters from aged oriental tobacco employing supercritical fluids have been completed. Underivatized sucrose ester-rich extracts were obtained using supercritical CO2 at densities greater than 0.73 g/mL. Lower density CO2 provided extracts with notable amounts of tobacco derived material; yet, no detectable sucrose ester content. Preparative supercritical fluid chromatography (SFC) provided for an additional purification of the sucrose ester-enriched fraction after column optimization. Structural assignments of the SFC fractions were facilitated using gas chromatography/mass spectrometry (GC/MS) accompanied by N, O-bis(trimethylsilyl)trifluoroacetamide-dimethylformamide (BSTFA-DMF) derivatization of the free hydroxyl groups and high performance-liquid chromatography/mass spectrometry (HPLC/MS). From a relative quantitative perspective regardless of tobacco type, sucrose esters having an acetyl group on C6 of the glucose function (Group III) were in higher concentration compared to both the concentration observed for sucrose ester of Group I (acetyl group on C3 of fructose) and sucrose ester of Group II (no acetyl group on either glucose or fructose). Saturated fatty acid constituents were found to range from a maximum total of 18 carbons to a minimum total of 13 carbons. Unsaturated and isomeric fatty acid homologues were detected within the Group II sucrose ester.

Accesso libero

Mathematical Modeling of a Lit-End Cigarette: Puffing Cycle and Effects of Puff Counts

Pubblicato online: 30 Dec 2014
Pagine: 46 - 62

Astratto

Abstract

The burning cycles of a lit-end cigarette were numerically simulated using a 3-D model that includes both the cigarette and its surrounding ambient air and the effects of buoyancy forces. The solid and gas phases were treated separately in a thermally non-equilibrium environment. The tobacco pyrolysis and char oxidation were modeled using multi-precursor models. The changes in tobacco column porosity and its subsequent effects on permeability and gas diffusivity were included. The mass, momentum, energy, and species transport equations were solved in a discretized computational domain using a commercially available computational fluid dynamics (CFD) code. The model was applied to puff a cigarette under different puffing intensities and the effects of puff volume, puff profile, and puff duration were studied. The results show that the model is capable of reproducing the major features of a burning cigarette during both smoldering and puffing. For the puffing and puff-by-puff cases, the solid and gas temperatures as well as those mainstream smoke constituents predicted by the model are in a good agreement with experimental results. A parametric study shows the significant effect of puff volume, puff profile, ventilation rate, and puff counts on solid and gas phase temperatures as well as gaseous species concentrations and mainstream smoke delivery. The buoyancy forces have shown to be very important in both smoldering and puffing.

Accesso libero

Letter to the Editor: Tobacco Research and Its Relevance to Science, Medicine and Industry

Pubblicato online: 30 Dec 2014
Pagine: 63 - 65

Astratto

Pianifica la tua conferenza remota con Sciendo