a Wide Range of Flavoring-Carrier Fluid adducts Form in E-Cigarette Liquids.

Introduction:
This article reports a study on the formation of flavoring-carrier fluid adducts in e-cigarette liquids. The study identifies the range of flavoring molecules that form adducts with propylene glycol (PG), vegetable glycerine (VG), and methanol in e-liquid products. The study also investigates the time frame in which flavoring-solvent adducts form under standard storage conditions and identifies adduct peaks present within the GC-MS analysis of e-liquid and flavoring concentrate samples.

Key Points:

* The study identifies 36 common e-liquid flavoring molecules from a range of chemical class groups and exposes them to PG, VG, or methanol.
* adduct formation was observed, with 14 of the flavoring molecules reacting with methanol, 10 reacting with PG, and 10 reacting with VG.
* Furfural PG and VG acetals, valeraldehyde PG and VG acetals, veretraldehyde PG and VG acetals, p-anisaldehyde PG and VG acetals, and piperonal VG acetal were confirmed for the first time.
* adducts formed by reaction with ketone-containing flavoring molecules were also observed for the first time.
* The presence of these acetals was confirmed in 32% of commercial e-liquid products analyzed (N = 142).
* The study has established a range of flavoring molecules that are able to react with solvent components PG and VG in e-liquids under standard storage conditions.
* These newly identified adducts need to be further assessed to determine their toxicological safety.

Main Message:
The study has identified a range of flavoring molecules that form adducts with PG, VG, and methanol in e-cigarette liquids. These adducts need to be further assessed for their toxicological safety, as they may have differing toxicological properties than their parent compounds. The study highlights the importance of monitoring the chemical composition of e-cigarette liquids, as the formation of these adducts may have implications for the health of e-cigarette users. The study also underscores the need for further research to determine the potential health risks associated with e-cigarette use.

Gschwend G, Jenkins C, Jones a, Kelso C, Morgan J. a Wide Range of Flavoring-Carrier Fluid adducts Form in E-Cigarette Liquids. Chemical research in toxicology. 2023;36(1):14-22. doi:10.1021/acs.chemrestox.2c00200