AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
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Partition of Free Base and Protonated Nicotine in Electronic Cigarette Liquids and Aerosols
Ahmad El Hellani, Rachel El Hage, Rima Baalbaki, Rola Salman, Soha Talih, Alan Shihadeh, NAJAT A. SALIBA, American University of Beirut
Abstract Number: 455 Working Group: Electronic Cigarettes - Particle Generation
Abstract As with other tobacco aerosols, nicotine delivery from e-cigarettes (ECIG) depends on the total nicotine and its partitioning between free-base (Nic) and protonated (NicH+) forms. Previous studies of ECIG nicotine emissions have generally reported “nicotine yield” without attention to whether the methods employed resulted in quantification of the total nicotine or only one of its forms, making reported results difficult to compare across studies, or to evaluate against reported blood exposure. This study reports a convenient method for determining total nicotine and its partitioning in ECIG liquids and aerosols. Apparent pH was found to correlate with nicotine partitioning and can provide a useful indirect measure when chromatography is unavailable. Standard and commercial ECIG liquids and aerosols were analyzed and it was found that aerosols exhibit higher Nic concentration than the parent liquids and that differences in nicotine partitioning across ECIG liquids carry over to the inhaled aerosol, and may influence nicotine delivery. The notion that Nic is the only form that can be volatilized upon heating and that the presence of NicH+ in the aerosol likely derives from the recombination of Nic with H+ in the propylene glycol / glycerin (PG/VG ) matrix of the aerosol droplets is investigated and discussed.