Investigation of TSNA formation in electronic cigarette liquids and aerosols
Electronic cigarette (e-cigarette) formulations typically contain tobacco derived nicotine and therefore, may contain other tobacco related components such as trace levels of tobacco specific nitrosamines (TSNAs), nitrite, and minor alkaloids. Previous reports including work in our laboratories, suggest that TSNAs are present in e-cigarette liquids (e-liquids) and aerosols. The objective of this work was to investigate the possible formation of TSNAs in e-liquids and aerosols. There are reports in the literature that nitrite can react with nicotine and minor alkaloids in tobacco and cigarette smoke to form TSNAs. However, there are no literature reports on the effect of tobacco related compounds on the formation of TSNAs in e-liquids and aerosols. These studies were conducted by fortifying (spiking) nicotine containing e-liquids (mixture of propylene glycol/glycerin/water/nicotine) with nitrite, nitrate, ammonia, and minor alkaloids. The fortified e-liquids were analyzed to assess if TSNAs were formed. These e-liquids were used to fill e-cigarettes to determine the transfer and potential formation of TSNAs during the aerosolization process. Model systems were used to provide an understanding of the TSNAs formation pathways. The experiments demonstrated that nitrite led to the formation of TSNAs in e-liquids and e-cigarette aerosol. This information should be useful for regulators and manufacturers when making science-based decisions on which harmful and potentially harmful constituents (HPHCs) and constituents to monitor in e-vapor products.