Enhancement of Benzene Emissions in Special Combinations of Electronic Liquid Mixtures

Abstract

Introduction— Electronic nicotine delivery systems (ENDS) are battery-powered smoking devices introduced to the market as safer alternatives to combustible cigarettes. Upon heating the electronic liquid (e-liquid), aerosols are released, including several toxicants such as volatile organic compounds (VOCs). Benzene has been given great attention as a major component of the VOCs group as it increases cancer risk upon inhalation. In this study, several basic e-liquids were tested for benzene emissions. Methods— Aerosol Lab Vaping Instrument was used to generate aerosols from ENDS comprised of different e-liquid combinations: vegetable glycerin (VG), propylene glycol (PG), nicotine (nic), and benzoic acid (BA). The tested mixtures were PG, PG+nic+BA, VG, VG+nic+BA, 30/70 PG/VG, 30/70PG/VG+nic+BA. A carboxen polydimethylsiloxane fiber of a solid phase micro-extraction was placed in a gas cell to trap benzene emitted from ENDS. Collection was done using an online dynamic/static mode; benzene was adsorbed by the fiber during the puffing process and for an extra 15 min until reaching equilibrium. Then, using gas chromatography-mass spectrometry, benzene was quantified. Results— Benzene was quantified in VG, but not in PG or PG/VG mixture. However, benzene concentration increased in all tested mixtures upon the addition of nicotine benzoate salt. Interestingly, benzene was emitted at the highest concentration when BA was added to PG. However, lower concentrations were found in the PG/VG and VG mixtures with BA. Conclusions— Both VG and BA are sources of benzene. Enhanced emission, however, is mostly noticed when BA is mixed with PG and not VG.