First Advisor

Robert M. Strongin

Date of Award


Document Type


Degree Name

Bachelor of Science (B.S.) in Biology and University Honors




Electronic cigarettes -- Additives, Cigarette smoke -- Composition, Cigarette smoke -- Analysis, Coloring matter -- Effect of temperature on, Food additives




Prior studies of e-liquid thermal degradants do not reflect many of the potential health hazards related to e-cigarettes. Although current studies have focused on solvents and flavoring additives in e-cigarette formulations, there have been no prior reports on the identity and levels of synthetic dye additives. Therefore, the purpose of this study was to identify and quantify these compounds to enhance understanding of the risks associated with the inhalation of colored e-liquids. Furthermore, e-liquids were subjected to thermal degradation under normal vaping conditions to quantify the sulfur oxides (SOx) content indicating dye decomposition. The dyes were analyzed by a combination of high-performance liquid chromatography and high resolution mass spectroscopy. The thermal decomposition of dyes in vaporized e-liquid samples was studied by ion chromatography. The findings of this investigation revealed that e-liquid manufacturers added synthetic dyes in concentrations comparable to those used in the food industry. In addition, SOx were present in the aerosolized e-liquids suggesting that dyes undergo thermal degradation. The aerosol samples contained a substantial amount of free chloride, which could be associated with a breakdown of the sucralose molecules, whose presence in the e-liquids was confirmed by nuclear magnetic resonance.


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