Carryover of neotame, WS-23, and other additives from popular disposable e-cigarettes to aerosol.

Abstract

Introduction : Disposable e-cigarette devices are popular among youth with fruit and candy flavored products dominating the market. While the addition of novel sweeteners and synthetic coolants has been quantified in the e-liquid of such devices, the relative amount of these compounds transferred into the aerosol and inhaled by users remains unknown. In this study, popular US disposable e-cigarette devices were analyzed for coolant, sweetener, and nicotine concentration, and subsequent carryover to aerosol was determined using an established protocol with cold-finger traps to collect aerosol. Methods 12 popular disposable e-cigarettes were identified and purchased between 2023-26, and 3 Sensa devices labeled as "0-nicotine" and 2 SpreeBar devices labeled to contain "Metatine" (6-methylnicotine) were also included to probe for the effect of nicotine on carryover. Menthol, nicotine, 6-methylnicotine (6MN), the synthetic coolants WS-23 and WS-3, and the artificial sweeteners neotame and sucralose were quantified in the liquids and the generated aerosol (20 puffs in triplicate) of 17 disposable e-cigarettes using GC-FID and LC-MS-MS. Results Neotame and WS-23 were present in all 17 devices at concentrations ranging from 0.05-2.73 mg/g and 3.52-35.0 mg/g, respectively. Nicotine was found in 11/17 devices, menthol in 9/17, WS-3 in 4/17, sucralose in 2/17, and 6MN in 2/17. Mean carryover rates to aerosol were: Neotame 40 ± 13%, WS-23 84 ± 9%, nicotine 88 ± 12%, menthol 81 ± 8%, WS-3 88 ± 10%, and sucralose and 6MN carryover ranged from 26-54% and 72-77%, respectively. Conclusions Although carryover rates to aerosol were lower for sweeteners compared to nicotine and coolants, users of these devices can be expected to be exposed to substantial amounts of the quantified 6 compounds. It is unclear whether neotame is thermally stable or breaks down during the aerosolization process. This study aims to provide a foundation for future toxicological and pharmacological studies that are needed to better understand the implications of chronic inhalation of neotame, WS-23 and the other tested compounds.