Regulatory authorities are currently discussing the measurement of and imposition of ceilings on certain smoke analytes, the so called "Hoffmann analytes". However, as a prerequisite, the measurement methods and the tolerances around the measurements first need to be established. In 1999, the Cooperation Centre for Scientific Research Relative to Tobacco (CORESTA) set up a Task Force "Special Analytes" to deal with analytical methodology for measuring "Hoffmann analytes" under International Standard (ISO) smoking and to work towards the standardisation of methods. This paper describes the output and conclusions from a 2005-2006 joint experiment made within the Task Force representing laboratories currently able to analyse these compounds. Data were obtained on most "Hoffmann analytes" from reference cigarettes (2R4F and 1R5F), collecting data according to the existing methods used by the nineteen participating laboratories, in order to describe the within and among laboratory variability and to see which methods could most benefit from more rigorous standardisation work. In some cases, the applied statistical analysis found that methods could not well differentiate the 1R5F and 2R4F cigarettes of differing 'tar' yield. This was explained, in part, by the broad range of methods used by the participating laboratories but also indicated that there were significant inadequacies in the choice of some methods or weaknesses in their application. Results indicate that "Hoffmann Analyte" data are generally more variable both within and among laboratories than nicotine free dry particulate matter (NFDPM); nicotine and carbon monoxide due to their lower smoke yields. Accordingly, tolerances around methods adopted for regulatory purposes will need to be proportionately higher. Methods for benzo[a]pyrene (B[a]P) and tobacco-specific nitrosamines (TSNAs), already taken to CORESTA recommended methods or ISO standardised methods through the efforts of this Task Force, give some of the most reproducible results, showing the value of this process. However, these data strongly suggest that even these analytes have much higher among-laboratory variability than for NFDPM, nicotine and CO and, based on the only two available one point in time studies, may need tolerances in the range of 35-45% for B[a]P and 26-55% for TSNAs, if they are to be measured for regulatory purposes. The collected data is useful to participating laboratories for internal method validation and laboratory accreditation, and data comparisons with others allow laboratories to identify strengths and weaknesses in their current methods. However, much work still needs to be carried out to take most of the methods towards standardisation. Although some fundamental differences or areas of concern around the methodology are discussed herein, they are not comprehensive and there may be others that need to be addressed before methods can be considered ready to take to a Recommended Method and/or to an ISO Standard. These methodological issues are being addressed in furth...

A recommended method has been developed and published by CORESTA, applicable to the quantification of selected carbonyl compounds (acetaldehyde, formaldehyde, acetone, acrolein, methyl ethyl ketone, crotonaldehyde, propionaldehyde and butyraldehyde) in cigarette mainstream smoke. The method involved smoke collection in impinger traps, derivatisation of carbonyls with 2,4-dinitrophenylhydrazine (DNPH), separation of carbonyl hydrazones by reversed phase high performance liquid chromatography and detection by ultra violet or diode array.At the start of the process it was determined that most laboratories participating in the CORESTA Special Analytes Sub-Group (SASG) used a similar method involving such derivatisation and so this was chosen as the basis of the recommended method. Initial joint experiments, specific experiments by single laboratories and ongoing discussions addressed some methodological aspects that needed to be considered before moving to a recommended method.As a first step, a joint experiment by 17 laboratories was carried out in 2009-2010 that investigated three features of the methodology on two reference cigarettes (3R4F and CM6) considered most important by SASG members. These were the volume of the impinger solution (25 or 35 mL); the type of mineral acid (perchloric or phosphoric) used to initiate the derivatisation and the time of derivatisation (5 or 30 min) before terminating the reaction with TrizmaTM base. Overall, it was concluded that these studied parameters in the methodology seemed to have little effect on the overall yield data, compared to the underlying variability among laboratories. The 25 mL impinger solutions appeared to give somewhat higher yields, although not with statistically significant differences, than those obtained when using 35 mL solutions.Some laboratories volunteered to carry out other investigations, for example, to confirm the identity of both the Eand Z-isomeric acetaldehyde hydrazone peaks within the chromatogram of smoke carbonyls and to investigate methodology factors influencing the hydrazoneisomerisation.The CORESTA recommended method (CRM) was produced through a final collaborative experiment involving 15 laboratories from 11 countries using 7 linear and 8 rotary smoking machines. Some notes are included in the CRM to inform other laboratories that might wish to adopt the method, concerning the main features that need to be well controlled to provide data as robust as possible and to provide similar repeatability and reproducibility data.Statistical evaluations were made according to ISO 5725 recommendations and are included. As expected from previous work on other smoke components, the levels of reproducibility of carbonyl yields 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 67-125% for formaldehyde; from 24-55% for acetaldehyde; from 41-108% for acetone; from 45-73% for acrolein; 31-75% for propionaldehyde; from 63-140% for crotonaldehyde; from 62-90% for 2-butanone and from 42-58% for butyraldehyde. The lowest “tar” yielding product gave the most variable data. These levels are generally in line with those determined for selected volatiles.

Cigarettes with similar design features but with either cellulose acetate or dual carbon filters were made at 1-mg and 13-mg “tar” levels, as determined under the ISO smoking procedure. Products were smoked under the ISO, Massachusetts and Canadian smoking regimes to provide per-cigarette and per-puff yields of twelve vapour phase (VP) smoke components. The yields generated at the lit end of the cigarette and the significant yield reductions caused by filter ventilation, selective (carbon) adsorption, tobacco rod ventilation and diffusion were estimated in a modelling approach. For a “1-mg tar” carbon-filtered product it was estimated that the VP generated at the lit end was reduced by 99.4% to a machine yield of 17 µg/cig under ISO smoking conditions. Under the Canadian regime with 100% vent blocking, the estimated total VP was lowered 20% by tobacco rod effects and 15% by carbon filter adsorption giving a machine yield of 3487 µg/cig. The carbon filter adsorbed less efficiently partly due to the artificially high smoke temperatures through the filter that would probably not be tolerated by human smokers. Under the Massachusetts regime with 50% vent blocking, conditions better associated with human smoking, the total VP was lowered 51% by filter ventilation, 22% by tobacco rod effects and 17% by carbon filter adsorption giving a machine yield of 659 µg/cig. Ventilation is used to achieve “tar”/nicotine/carbon monoxide yield ceilings at 10/1/10 mg based on the current ISO smoking method. If future regulations were to mandate further reductions in VP then this will only be selectively achieved by increasing filter or tobacco rod ventilation/porosity or by using selective adsorption. It is inevitable that manufacturers will need to add further ventilation into their product to comply with such regulations and this should be reflected in any smoking regime. Furthermore, regimes with 100% vent blocking, that do not produce data reflecting the significant reductions in VP yields, provided to the smoker by ventilation, are misleading and their results will not correlate with relevant biomarker data. When proposing a different smoking regime, it is essential to understand the generation and transfer of smoke within cigarettes and factors involved in the subsequent data interpretation as described in this work. For regulatory evaluation purposes, cigarette characterisation using a regime that removes ventilation, one of the main design tools, is more misleading than the current ISO regime or one with partial vent blocking.

SUMMARYJoint experimental work carried out in 2006 by the CORESTA Special Analytes Task Force compared yield data on a wide range of smoke constituents obtained from reference cigarettes according to the existing methods used by participants. This work identified that the methodologies that were used to determine yields of selected volatiles in mainstream smoke under the ISO smoking regime would benefit from further joint experiments. This report describes the output from the 2008 Joint Experiment on selected volatiles in smoke (1,3-butadiene, benzene, toluene, acrylonitrile, and isoprene). Its objectives were to investigate the main weaknesses and influencing factors in methodologies used by the participating laboratories and their effects on yield variability before deciding on one to take forward to a CORESTA recommended method. The Task Force considered this step was necessary before progressing to a full collaborative study using a recommended method. An experimental protocol was devised to investigate several factors such as the use of different calibration standards and the efficiencies of different trapping systems. The effects of other general factors identified from supplied methodology information as differing across laboratories were also analysed. A statistical assessment was made of their possible influence on smoke yields and yield reproducibility across different laboratories and is discussed in this report. Between-laboratory variability has been reduced since the last study indicating that some laboratories have improved their methodology although extremely high values for the among-laboratory variability were still found for acrylonitrile (> 100%) and 1,3-butadiene (~ 80%) when related to the mean yields.The means to reduce the variability in acrylonitrile and 1,3-butadiene yields are not apparent from the data and interpretations made in this study. However, when the different laboratories use the same methodology during the development of a recommended method at the next development stage then it is hoped that this high level of variability for acrylonitrile and 1,3-butadiene will be reduced to similar levels to those found for benzene, toluene, and isoprene. As in previous work, it was recognised that although a more intense smoking regime may be introduced into the regulatory arena in the future, it was decided that the current ISO smoking regime should be used for this joint experiment. A wider range of product styles will be investigated when the Task Force works towards a recommended method to take account of differing blends and designs and the potentially greater product variability of commercial products. This will provide robust estimates of within-laboratory repeatability and among-laboratory reproducibility and is intended to be reported in a later paper. [Beitr. Tabakforsch. Int. 24 (2011)

Since 1999, the CORESTA Special Analytes Sub Group (SPA SG) has been working on the development of CORESTA Recommended Methods (CRMs) for the analysis of cigarette smoke components. All CRMs have been posted on the CORESTA website and several associated papers published. In this study, 21 laboratories shared data and in-house methodologies for 28 additional smoke components of regulatory interest to prioritise the development of further CRMs. Laboratories provided data, where available, from CORESTA monitor test pieces (CM6 and CM7) and Kentucky Reference Cigarettes (1R5F / 3R4F) covering the period 2010-2012 obtained under both the ISO 3308 and Health Canada Intense regimes. Scant data were available on the CORESTA monitor test pieces and the Kentucky 1R5F reference. The greatest amount of data was obtained on the Kentucky 3R4F and this was used in the analyses described in this paper. SPA SG discussions provided invaluable insight into identifying causes and ways of reducing inter-laboratory variability which will be investigated in joint experiments before embarking on final collaborative studies using draft CRMs to obtain mean yields, repeatability and reproducibility values. Phenolic compounds (phenol, 3 cresol isomers, hydroquinone, catechol and resorcinol) gave consistent results by liquid chromatography (LC) separation and fluorescence detection after extracting collected “tar” on a Cambridge filter pad (CFP). Yields were similar to those obtained by a derivatisation method followed by gas chromatography - mass spectrometry (GC-MS) analysis. Similar ratios of phenols were also obtained from each method. Of the 28 studied analytes, the between-laboratory variability was lowest for the phenols. Hydrogen cyanide was derivatised using various reagents and the colour development measured after continuous flow analysis (CFA) by ultra-violet absorbance. Although, methodologies gave reasonably consistent results, investigations on the trapping system and on differences in the application of the various colour complexes used for quantification with UV absorbance is required. Ammonia analysis was carried out by ion chromatography (IC) followed by conductivity measurement and gave very similar results between laboratories. Yields were similar to those obtained by a derivatisation method followed by LC/MS-MS methodology. Optimal conditions for the separation of ammonium from interfering ions and minimizing artefactual ammonia formation from other smoke components need to be addressed during standardisation. Aromatic amine methods involved either LC/MS-MS separation and detection or derivatisation by one of two main reagents followed by GC-MS analysis. Yields were at similar but variable levels using these different techniques. It is currently unclear which method will be taken to a CRM. In general, four compounds were measured (1-amino naphthalene; 2-amino naphthalene; 3-amino biphenyl and 4-amino biphenyl) although two others were incorporated in methodologies used by 3 laboratories (o-anisidine and o-toluidine). Semi-volatiles (pyridine, quinoline and styrene) were often integrated with the selected volatiles method by measurement of the combination of CFP extracts and the contents of the impinger trapping system. Less data, obtained mainly by inductively-coupled plasma - mass spectrometry (ICP-MS), were available on metals (cadmium, lead, arsenic, beryllium, cobalt, chromium, nickel, selenium and mercury) in smoke. Trace metals were the most variable of the studied smoke analytes. Optimisation of the digestion step to remove the organic matrix needs to be addressed. As a consequence of this study and subsequent discussions within the Sub Group, it was decided to prioritise the development of CRMs for selected phenols followed by hydrogen cyanide and ammonia.

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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.

Three tobacco industry based laboratories determined selected mainstream components using their established in-house methods. Machine smoking was done according to the ISO smoking regime. The Test cigarettes smoked for this investigation were manufactured with different amounts of added glycerol, cocoa powder and sucrose. Variability between the three laboratories differed clearly for the analyzed smoke components. No overall effects due to the added ingredients on smoke components could be found. The high ‘tar’ products with the highest lodading of sucrose showed a slight increase in formaldehyde emissions among all three laboratories.