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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.

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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.

A CORESTA Recommended Method (CRM 75) has been developed and published, applicable to the quantification of tobacco-specific nitrosamines (TSNAs), namely, Nnitrosonornicotine (NNN), N-nitrosoanabasine (NAB), Nnitrosoanatabine (NAT) and 4-(N-nitrosomethylamino)-1-(3-pyridyl)-1-butanone (NNK) in cigarette mainstream smoke. The method involves smoke collection on a Cambridge filter pad under both ISO 3308 and the intense conditions adopted by Health Canada. An internal standard solution is added to the smoke collected on the pad and, after extraction, an aliquot is separated and quantitatively analysed by liquid chromatographytandem mass spectrometry (LC-MS/MS).CRM 63 involving gas chromatography coupled with a thermal energy analyser (GC-TEA) was previously developed by the CORESTA Special Analytes Group that had been set up to develop recommended methods on smoke components. However, by 2009 most laboratories had moved to similar LC-MS/MS methods for TSNA analysis and so this technique was chosen as the basis of a new CRM and to complement CRM 63. Initial joint experiments, specific experiments by single laboratories and ongoing discussions identified methodological aspects that needed to be ‘standardised’ before moving to a CRM.A joint experiment by 15 laboratories was carried out in 2010-2011 that investigated and identified important methodological features that needed to be controlled or clarified. CRM 75 was produced through a final collaborative experiment involving 20 laboratories from 12 countries using both linear and rotary smoking machines. Some notes are included in the CRM to inform other laboratories that might wish to adopt the method, concerning aspects 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 guidelines and are included. Under ISO smoking, the levels of reproducibility (R) expressed as a percentage of the mean of TSNA yields across laboratories are much greater than the levels found for “tar”, nicotine and carbon monoxide and given in the relevant ISO standards. The R value was expressed as a percentage of the mean yield amonglaboratories and across all of the studied products. UnderISO smoking R% values ranged from 25-60% for NNN; from 31-85% for NNK; from 47-58% for NAT and 40-99% for NAB. These levels are generally in line with those determined previously for TSNAs in CRM 63 and for other smoke analytes studied by the Special Analytes Group.Under ‘intense’ smoking, R% values ranged from 30-88% for NNN; from 37-79% for NNK; from 47-83% for NAT and 42-111% for NAB. A plot of R against mean yields suggests that the ‘intense’ regime gives similar or slightly worse reproducibility than the ISO regime in spite of the higher yields generated.