Analysis of mercury in mainstream smoke or aerosol
Mercury has been identified as a harmful, or potentially harmful, constituent of tobacco smoke. For this reason, methods for quantifying the mercury content in the mainstream smoke of cigarettes, or in the aerosol of potential Reduced Risk Products (RRPs), are of interest.
The purpose of the developed method is to quantify mercury in the mainstream smoke of cigarettes and in the aerosol of potential RRPs by Inductively Coupled Plasma Mass Spectrometry (ICP-MS).
The mercury content in the particulate and gas vapour phases of mainstream smoke from Kentucky reference cigarette 3R4F and the aerosol of potential RRPs (iQOS) was evaluated. The mainstream smoke was generated under ISO smoking regimen. The particulate phase was collected using an electrostatic precipitation trap and in parallel the vapour phase was trapped using two impingers. After collection, both phases were analysed by ICP-MS and compared. The mainstream smoke and the aerosol were trapped in an acid solution and analysed by ICP-MS.
Only mercury in the gas vapour phase could be quantified whereas the signal of mercury in the particulate phase was found close to those of blank solutions and was not measurable. The nominal content obtained under Health Canada (HC) and ISO smoking regimens was respectively 4.5 ng/cig and 2.0 ng/cig for 3R4F and 1.1 ng/item and 0.45 ng/item for RRPs.
The method has been validated for the mercury quantification in the gas vapour phase of mainstream smoke from Kentucky reference cigarette 3R4F and the aerosol of potential RRPs (iQOS) collected under HC and ISO smoking regimens, analysed by ICP-MS. Validation results demonstrated the selectivity, precision, linearity and accuracy of the method (from 25 pg/mL to 1000 pg/mL).
 Reduced Risk Products (RRPs) is the term used to refer to products with the potential to reduce individual risk and population harm in comparison to smoking cigarettes.