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

With deep-felt sadness we have to inform our readers that Dr Dietrich K. Hoffmann passed away at his home inLarchmont, N.Y. on April 20th at the age of 86 years. We will publish an obituary honoring this notable tobacco scientistin our next issue.

In this issue we publish the presentation of Drs Thomas A. Perfetti and Alan Rodgman at the 2010 CORESTA Meeting inEdinburgh when they were awarded the 2010 CORESTA Prize. Dr Hubert Klus kindly contributes a Guest Editorial.

We are pleased to continue the publication of the laudations for the recipients of the Tobacco Science ResearchConference Lifetime Achievement Award. In 2010, the award was presented to Dr William Kerr Collins. The laudationwas delivered by Dr J. Michael Moore. We started the series in issue 21/5 (2005) with the first two recipients of thisprestigious award, Dr Alan Rodgman and Dr Dietrich Hoffmann, followed by Dr Tien C. Tso in issue 21/8 (2005) and DrRichard R. Baker in issue 22/4 (2007).

Finally, we have asked François Jacob, who was CORESTA's Secretary General for more than 20 years, to recount someof his impressions and experiences during a most fulfilling part of his career.

Dr Thomas A. Perfetti and Dr Alan Rodgman wereawarded the CORESTA Prize in 2010. The two scientistswere honored by CORESTA for their lifetime researchwork on tobacco and tobacco smoke, culminating in theexcellent and highly recommendable compendium “TheChemical Components of Tobacco and Tobacco Smoke”published in 2009. It is an honor for the editors to publish in BeiträgezurTabakforschung International/CONTRIBUTIONS TO TOBACCO RESEARCH the presentation given byDrsPerfetti and Rodgman at the 2010 CORESTAplenary session in Edinburgh.

It is my distinct pleasure to make this presentation of the TSRC Lifetime Achievement Award to Dr Bill Collins from NC State University. Bill is well known in academic and industry circles for his contributions to Tobacco Science. Some have suggested that Bill Collins is the single person most identified with flue-cured tobacco at NC State and probably world-wide.

Tobacco and tobacco smoke are both complex mixtures. We previously reported 8430 unique chemical components identified in these complex mixtures but two years later our updated number was 8889. Addition of unlisted isomers raised these numbers to 8622 and 9081, respectively. Our previous number of 4994 identified tobacco components is now 5229; our previous number of 5315 identified tobacco smoke components is now 5685. An operational definition of a complex mixture is as follows: A complex mixture is a characterizable substance containing many chemical components (perhaps thousands) in inexact proportions.

Detailed knowledge of the amount and type of each component within the substance is uncertain even with today's analytical technology. Although it has been estimated that as many as 100000 components are present in these complex mixtures, their analyses indicate that the vast majority of the mass of each of these complex mixtures accounts for the 8430 compounds reported previously. Over 98.7% of the mass of tobacco has been accounted for in terms of identified components in tobacco. Greater than 99% of the mass of whole smoke has been accounted for based on identified chemical components. Certainly, many more tobacco and tobacco smoke components are present in these complex mixtures but the total mass of these components obviously is quite small.

One of the significant challenges we face as a scientific community is addressing the problems of determining the risk potential of complex mixtures. Many issues are associated with toxicological testing of the complex mixture of tobacco smoke. Conducting valid experiments and interpreting the results of those experiments can be quite difficult. Not only is the test agent a complex mixture but also the tests are performed on species that have complicated life-processes. Interpretations of test results are often paradoxical. Significant progress has been made in the toxicological evaluations of complex mixtures in the last 80 years. The challenges we face in terms of testing the biological properties of tobacco smoke are substantial. The statement by DIPPLE et al. in their summary of the research on polycyclic aromatic hydrocarbons from the 1930s through 1980 is equally true today for the cigarette smoke situation:

…many important questions remain unanswered

…many questions persist despite the considerable progress that has been made.

Nitrogenous compounds such as amino acids and proteins are frequently analyzed in tobacco since they are considered precursors of toxicants in cigarette smoke. However, much less attention is given to other nitrogenous compounds such as amino sugars and deoxyfructosazines, although their concentration in tobacco can be equal to or even higher than that of most free amino acids. These nitrogenous compounds may contribute to the formation of toxicants in smoke, or may contribute to the sensory properties of cigarette smoke, reasons for which their analysis is important. This study describes a procedure for the analysis of adenosine, 2,5- and 2,6-deoxyfructosazines (DFs), mannosamine and glucosamine in tobacco. The analysis uses a liquid chromatographytandem mass spectrometry (LC/MS/MS) technique. Sample preparation for analysis consists of the extraction of the tobacco with a solution of 90% water and 10% methanol, followed by filtration. The separation of the analytes was done on a hydrophilic interaction liquid chromatography HILIC column using an isocratic procedure with a solvent consisting of 78% CH₃CN, 22% H₂O, that also contained 0.1 % HCOOH and 0.143 g/L CH₃COONH₄. The measurements were done using electrospray positive ionization mass spectrometric detection. The analytical procedure was validated and was proven very reliable. A number of tobaccos were analyzed, including several fluecured and Burley USA tobaccos, off-shore tobaccos, two

Oriental tobaccos, two green tobaccos, as well as tobaccos from commercial and Kentucky reference cigarettes. The ranges for the analytes per g tobacco were found between 0.4 and 20.3 µg/g for adenosine, between 0.0 and 608.5 µg/g for 2,5-DF, between 0.0 and 424.5 µg/g for 2,6-DF, between 12.5 and 415.5 µg/g for mannosamine and between 25.9 and 1885.7 µg/g for glucosamine. The study also indicated that the levels of DFs and that of the amino sugars in tobacco show a very good correlation. This correlation can be explained by the same source of the two classes of compounds, namely the reaction of (reducing) sugars and ammonia.

A recommended method has been developed and published by CORESTA, applicable to the quantification of selected volatiles (1,3-butadiene, isoprene, acrylonitrile, benzene, and toluene) in the gas phase of cigarette mainstream smoke. The method involved smoke collection in impinger traps and detection and measurement using gas chromatography/mass spectrometry techniques.

This report describes the final collaborative study applying the recommended method. It provides additional notes to inform other laboratories that might wish to adopt it, about some of the main features that need to be well controlled to provide data as robust and consistent as the data presented herein.

Data was provided by 15 industry-related and 4 independent laboratories and one governmental laboratory. Overall, 6 linear and 14 rotary smoking machines were used.

The joint experiments and collaborative work between the large number of participating laboratories has provided solutions to several methodological problems and reduced the high data variability that had initially been found particularly for 1,3-butadiene and acrylonitrile smoke yields.

Even so, the levels of reproducibility among laboratories are much greater than the levels found for ‘tar’, nicotine and carbon monoxide and given in the equivalent ISO standards. When expressing the reproducibility (R) value as a percentage of the mean yield among-laboratories and across all of the studied products, values ranged from 63-93% for 1,3-butadiene; from 36-62% for isoprene; from 41-110% for acrylonitrile; from 35-70% for benzene, and from 27-116% for toluene. For the higher ‘tar’ yielding products, the lower levels of variability were in line with those previously evaluated during Task Force work on standard methods for benzo[a]pyrene and tobacco specific nitrosamines. As expected, the lowest ‘tar’ yielding product gave the most variable data.