Abstract
We characterized the flavor chemicals in a broad sample of commercially available electronic cigarette (EC) refill fluids that were purchased in four different countries. Flavor chemicals in 277 refill fluids were identified and quantified by gas chromatography-mass spectrometry, and two commonly used flavor chemicals were tested for cytotoxicity with the MTT assay using human lung fibroblasts and epithelial cells. About 85% of the refill fluids had total flavor concentrations >1 mg/ml, and 37% were >10 mg/ml (1% by weight). Of the 155 flavor chemicals identified in the 277 refill fluids, 50 were present at ≥1 mg/ml in at least one sample and 11 were ≥10 mg/ml in 54 of the refill fluids. Sixty-one% (170 out of 277) of the samples contained nicotine, and of these, 56% had a total flavor chemical/nicotine ratio >2. Four chemicals were present in 50% (menthol, triacetin, and cinnamaldehyde) to 80% (ethyl maltol) of the samples. Some products had concentrations of menthol (“Menthol Arctic”) and ethyl maltol (“No. 64”) that were 30 times (menthol) and 100 times (ethyl maltol) their cytotoxic concentration. One refill fluid contained cinnamaldehyde at ~34% (343 mg/ml), more than 100,000 times its cytotoxic level. High concentrations of some flavor chemicals in EC refill fluids are potentially harmful to users, and continued absence of any regulations regarding flavor chemicals in EC fluids will likely be detrimental to human health.
Highlights
Electronic cigarette (EC) consumers inhale aerosols that usually contain nicotine, propylene glycol and/or glycerol, and blends of flavor chemicals that directly contact the lining of the mouth and respiratory system[1,2]
The purpose of this study was to identify and quantify the flavor chemicals in a broad spectrum (277) of electronic cigarette (EC) refill fluids that were purchased in four countries to gain a better understanding of the range of chemicals and concentrations used in these products
Our findings draw attention to the fact that ECs serve the dual purpose of delivering both nicotine and flavor chemicals and that some of the flavor chemicals are used at concentrations far in excess www.nature.com/scientificreports of the acceptable levels found in other consumer products
Summary
Electronic cigarette (EC) consumers inhale aerosols that usually contain nicotine, propylene glycol and/or glycerol, and blends of flavor chemicals that directly contact the lining of the mouth and respiratory system[1,2]. Instances of adverse health effects, some of which involve the respiratory system, such as bronchiolitis obliterans and acute eosinophilic pneumonia, have been attributed to EC use[4,5]. Cultured cells and animal models exposed to EC fluids and aerosols show increased oxidative stress, inflammatory responses, and impaired pulmonary defenses that may contribute to adverse health effects[6,7,8,9]. The constituents of EC fluids and aerosols that cause adverse effects in cells and animals are beginning to be identified. Government agencies, such as the National Institute of Occupational Safety Health (NIOSH), have published inhalation exposure guidelines to protect workers who manufacture flavor chemicals from adverse health effects[16]. Two commonly used flavor chemicals were further evaluated for cytotoxicity using an in vitro model based on human respiratory cells
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
