To reduce the risks associated with combustible nicotine products, efforts have focused on the production of non-combustible alternatives such as electronic nicotine delivery systems (ENDS). At the 75th TSRC, we presented our findings into potential ketene generation through thermal degradation of ester flavorants during ENDS aerosol generation. As part of this, we observed the creation of products formed from reactive species generated by propylene glycol (PG) and glycerol (VG), speculating that these species may have been small organic acids (SOA). Here we present our findings in a study looking at SOA generation from PG, VG, and select ester flavorants.

Model e-liquids were vaped under regular-to-moderate experimental conditions (0.7–1.8 Ω coils, 12–75 W power setting, 55/3/30 puff regime) using the CORESTA recommended device (Aspire Nautilus™ tank system with an EvolvTM Reference Mod DNA 75 Color battery), collected in puff blocks to dryness, and analyzed using ion chromatography. Generally, the amount of SOA produced was dependent on the power setting and collection duration/puff block. PG and VG both contributed to the formation of acetic acid (0.112–8.07 µg/puff & 0.207–86.3 µg/puff, respectively) and formic acid (0.122–0.713 µg/puff & 0.229–5.43 µg/puff respectively). VG was shown to be primarily responsible for the formation of propionic acid (ND–11.2 µg/puff). At higher power settings, acrylic acid was also observed at levels up to 2.46 µg/puff along with conversion of ester flavorants to their corresponding acid to varying degrees. Though not on the FDA’s published HPHC list, these acids have associated hazards that warrant further investigation into their production and effects of long-term exposure.