AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
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Compositional Changes and Gas-Particle Partitioning of Unflavored E-Cigarette Carrier Liquids Propylene Glycol and Glycerol
SARAH SUDA PETTERS, Yael-Natalie Escobar, Grace Nipp, Yue Zhang, Tianqu Cui, Ilona Jaspers, Jonathan Thornburg, Jason Surratt, University of North Carolina at Chapel Hill
Abstract Number: 602 Working Group: Health-Related Aerosols
Abstract Since their introduction to the market in 2007, electronic cigarettes (e-cigarettes) have been widely adopted as a potentially safer alternative to tobacco cigarettes. Developing suitable techniques to study the long-term health effects of e-cigarette aerosol exposure is important because e-cigarettes are a relatively new and poorly characterized phenomenon with a growing market share. E-cigarettes generate aerosols by vaporizing a mixture of polyols, typically containing nicotine and flavor additives, in a heated cell, and then routing the saturated mixture to the mouthpiece, where it cools and forms a cloud of droplets. In this work we characterize the composition and gas-particle partitioning of e-cigarette aerosols. Unflavored solvents composed of propylene glycol (PG) and glycerol (GLY) were atomized in PG:GLY ratios of 0:100, 20:80, 35:65, 50:50, 65:35, and 100:0. Two different atomization methods were employed: pneumatic atomization at room temperature and heated atomization using a commercially-available e-cigarette device. Filter samples of the undiluted aerosol were collected and extracted in methanol. PG, GLY, and speciated oligomeric products were identified using reverse-phase liquid chromatography (RPLC) and hydrophilic interaction liquid chromatography (HILIC) coupled with electrospray ionization high-resolution quadrupole time-of-flight mass spectrometry (ESI-HR-QTOFMS). Gas-particle partitioning for different permutations of PG:GLY was quantified by RPLC/ESI-HR-QTOFMS and modeled using a binary evaporation model with UNIFAC activity coefficients. Results show that the nascent aerosol equilibrates quickly and partitions to first order according to its liquid PG:GLY ratio. Dimers and trimers of PG and GLY were identified in samples. These oligomeric degradation products generated from common carrier liquids, if specific to e-cigarettes, have the potential to serve as biomarkers in studies assessing the health impacts of e-cigarette aerosols.