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CORESTA Congress, Edinburgh, 2010, SSPTPOST 08

Further investigations of temperatures and adsorption/desorption of volatile compounds in carbon filters under different smoking regimes

TEILLET B.; PURKIS S.; CAHOURS X.
Imperial Tobacco Group, Seita Research Centre, Fleury-les-Aubrais, France

Previous work on "7 mg ISO tar" cigarettes containing an activated carbon filter had shown a significant removal of volatiles in mainstream smoke under ISO smoking. Our work had also shown that high filter temperatures associated with the Canadian intense (CI) regime lead to a significant desorption of volatiles from carbon leading to an increase of mainstream smoke yield.This study investigated filter temperatures and volatile retention under the ISO, Massachusetts, WG9 option B (WG9B) and CI smoking regimes. Temperatures were measured in the middle of the carbon section. Smoke temperatures passing through the filter, were highest for the CI and lowest for the ISO smoking regime.Thermal desorption / gas chromatography / mass spectrometry analysis was used to monitor the relative distribution of volatiles between those adsorbed on the filter and those in the mainstream vapour phase according to the smoking regime. The experimental set-up was designed to evaluate the temperature effect on this relative distribution. A first experiment analysed the volatiles during smoking when placing the carbon section within the cigarette filter. A second experiment excluded the increase of temperature by placing the carbon section external to the filter and maintained at ambient temperature. The comparison of the resulting volatile distribution between those adsorbed in the filter and those delivered to mainstream smoke vapour phase allowed an estimation of the impact of temperature on the retention of volatiles.In comparison with ISO and CI regimes, the other regimes induce intermediate filter temperatures and intermediate reduction of carbon filter efficiency even though puff volumes are higher in the case of the WG9B than the CI regime, showing that partial ventilation blocking still allows filter cooling. Additionally, carbon filters are a well known technology to reduce vapour phase yield under ISO smoking but for the most volatile compounds this tends to decrease during more intensive smoking especially under the CI regime.