Determination of Aromatic Amines in Cigarette Mainstream Smoke - The CORESTA 2007 Joint Experiment

CORESTA joint experiment work in 2006 had compared data on a wide range of smoke constituents obtained from Kentucky reference cigarettes (1R5F and 2R4F), according to the existing methods used by participants. This work had identified that the methods used to determine aromatic amine yields in mainstream smoke would particularly benefit from further study to investigate the main weaknesses and influencing factors in their yield variability before progressing to full method standardisation. This report describes the output from a 2007 joint experiment to address these issues. Participating laboratories carried out experiments to investigate several factors that had been identified in the methodology as potential sources of variability. These were the amine derivative type, the derivatisation time and the point at which the addition of the internal standard for calibration occurred. A statistical assessment was made of their possible influence on aromatic amine smoke yields and yield reproducibility across different laboratories. Results showed that aromatic amines again had poor between-laboratory yield reproducibility. The stage at which the internal standard was added to the smoke sample had the most significant effect on yields. The least variable data were obtained when it was added directly after extraction from the filter pad rather than later in the process. It also appeared beneficial to use at least two calibration standards (i.e., an aminonaphthalene and an aminobiphenyl) to minimise yield differences although this recommendation was not supported by statistically significant data. Large differences in yields were not found when comparing the two studied derivatising agents especially when compared against the greater overall between-laboratory variability. Any differences between laboratories in total particulate matter and puff count at the smoke collection stage did not appear to significantly contribute to betweenlaboratory differences in yields. It appeared that some laboratories had significantly improved their methodology since the last study although high values for the between-laboratory reproducibility in this study were still found. It may be that significant improvements in reproducibility may not be forthcoming for compounds such as the aromatic amines measured at low nanogram smoke yields. Some important features that need to be controlled to minimise variability were identified in this study and will be incorporated within a collaborative study leading to a recommended method. Also, a wider range of product styles will need to be investigated, to determine the effects of differences in tobacco blends and product styles and the potential of greater product variability of commercial products. This should provide more robust estimates of within-laboratory repeatability and between-laboratory reproducibility