Electronic cigarettes (e-cigarettes) generate aerosol (particles in a gas matrix) by vaporizing the e-liquid, consisting of propylene glycol (PG), glycerol (GL), nicotine, and other additives. Aerosol enters the respiratory tract (RT) of the user, where part of it is deposited, while the rest is exhaled. Compounds in the gas and particle phase have different deposition mechanisms in the RT, thus determining the location of deposition. The location of deposition and amount of a compound will influence the biological response in the body. Identifying the composition of each constituent in the gas phase and particle phase would enhance the understanding of their deposition in the RT, thus absorption into the body. Study 1: assess the composition difference in aerosol particle phase (PP) from its e-liquid, and identify the mechanism associated with the composition difference. Gas chromatography analysis was conducted on e-liquid and aerosol PP for PG, GL, and nicotine. Experiments were designed to isolate the mechanism for composition difference by testing evaporation, aging, vaporization, and condensation. Study 2: streamline a methodology to study impact of user-specific parameters on aerosol deposition in e-cigarette users. A pilot study was conducted with participation of e-cigarette consumers to test the usability of exhale breath collection device. Feasibility of quantifying yield, exhale breath, puff and respiratory topographies were evaluated. Salivary cotinine boost was quantified to measure nicotine uptake. PG in aerosol PP showed a significant reduction from the e-liquid. Nicotine composition difference between e-liquid and the PP for non-acidified e-liquid was greater from acidified e-liquids. Study data is in agreement with the condensation model to explain the composition change of aerosol PP vs the initial e-liquid. The pilot study successfully quantified exhale breath composition, deposition efficiencies, salivary cotinine boost, puff and respiratory topographies. Findings confirmed the composition of aerosol PP to be different from its e-liquid and identified the mechanism for the difference. Pilot study successfully demonstrated the proof of concept to study the impact of user-specific parameters in e-cigarette users.

Publication Date


Document Type


Student Type


Degree Name

Chemistry (MS)

Department, Program, or Center

School of Chemistry and Materials Science (COS)


Nathan Eddingsaas

Advisor/Committee Member

Risa Robinson

Advisor/Committee Member

Hans Schmitthenner


RIT – Main Campus