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Chemical and Toxicological Characterization of Vaping Emission Products from Commonly Used Vape Juice Diluents
HUANHUAN JIANG, C.M. Sabbir Ahmed, Thomas Martin, Alexa Canchola, Iain Oswald, Jose Garcia, Jin Chen, Kevin Koby, Anthony Buchanan, Zixu Zhao, Haofei Zhang, Kunpeng Chen, Ying-Hsuan Lin, University of California, Riverside
Abstract Number: 147
Working Group: Health-Related Aerosols
Abstract
There have been an increasing number of reports on the detrimental vaping-related incidents, such as lung injury, lipid pneumonia, and the occurrence of seizures, which illicit a great health concern regarding the usage of vaping products including e-cigarettes and cannabis. The prevalence of vaping among adolescents has increased dramatically within the past decade for the reduced consumption of nicotine and lack of combustion needed to consume the product during vaping. The major components of vape juices and e-liquids are the viscosity enhancers, the percentage of which can reach up to 100%. Previous studies have reported that the thermal degradation and oxidation of commonly used viscosity enhancers (e.g., propylene glycol) can produce a large amount of highly toxic aldehydes (e.g., formaldehyde and acetaldehyde). Recently, a variety of new juice diluents have been introduced into the market. However, to date, the chemical compositions and toxicological characterization of vaping products from these juice diluents are largely unknown. This pilot study aims to provide a molecular and toxicological characterization of e-cigarette vaping products from seven commonly used viscosity enhancers, including propylene glycol, glycerin, medium-chain triglyceride (MCT) oil, triethyl citrate, squalane, vitamin E (tocopherol), and vitamin E acetate (tocopheryl acetate). The vaping products in both gas and particle phase were collected into two tandem impingers. Samples collected in isopropyl alcohol and o-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine hydrochloride (PFBHA) aqueous solution were applied to GC-MS and LC-MS for chemical analysis. Samples collected in LHC-9 cell culture media were applied for cell proliferation and cytotoxicity evaluation in human epithelial lung cells (BEAS-2B). Our study demonstrates that during vaping processes, changes in chemical composition of several commonly used vape juice diluents (also known as cutting agents) lead to the formation of toxic byproducts, including quinones, carbonyls, esters and alkyl alcohols. The resulting vaping emission condensates cause inhibited cell proliferation and enhanced cytotoxicity in human airway epithelial cells. In particular, we observed a high yield of duroquinone and durohydroquinone from the vaping of vitamin E and vitamin E acetate. This might help explain the recent outbreak of e-cigarette or vaping product use-associated lung injury that was linked to the vaping of e-liquid containing vitamin E acetate. These findings highlight the significant role of toxic byproducts in vaping-associated health effects.