Determination of Selected Volatiles in Cigarette Mainstream Smoke. The CORESTA 2008 Joint Experiment

Joint 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.