Summary
Introduction:
This text provides an in-depth analysis of the chemical composition of aerosols produced by Electronic Nicotine Delivery Systems (ENDS) and the potential health implications of exposure to these aerosols. The study utilizes Orbitrap mass spectrometry to identify unknown components in ENDS aerosol and the Toxicity Estimation Software Tool (TEST) from the US Environmental Protection agency (EPa) to predict the physicochemical features and evaluate the toxicity of newly compounds based on postulated molecular structures.
Key Points:
* The study identified more than 30 features in the aerosols of two open-system ENDS devices, including nicotine and its oxide compounds, ethyl maltol used in e-liquid flavors, and amines such as tributylamine and dibutylamine.
* Nicotine-N-oxide was detected in unused e-liquids and produced after the heating process, while nicotine-PG adducts were detected in samples subjected to heating.
* The fragmentation of nicotine compounds was studied using deuterated analogs, and major fragmentation pathways of protonated nicotine and its analogs were identified.
* The formation of nicotine-PG adducts was dependent on the power output of the ENDS, with a steep increase in the ratio of NIC-PG and nicotine at power outputs below 120 W.
* The EPa toxicity estimation tool TEST predicted that the melting point of NIC-PG is 105°C, water solubility 35 mg/L, and the average developmental toxicity of nicotine-PG adduct about 0.82.
* The nicotine-containing compounds that were identified could mimic and exacerbate the adverse developmental effects of nicotine, warranting a thorough toxicological characterization in future studies.
* The formation of NIC-PG adducts is concerning for in utero fetal brain development and the future health of offspring from pregnant women who may use ENDS as a substitute to tobacco cigarettes.
Main Message:
The study highlights the importance of understanding the chemical composition of ENDS aerosols and the potential health implications of exposure to these aerosols. The detection of nicotine-PG adducts, which are predicted to be developmental toxicants, is of particular concern for pregnant women and youth whose brains are still developing. The strong positive association between NIC-PG levels and device power supports regulating high-powered ENDS devices, and the existence of toxic compounds in the aerosol phase motivates a change in ENDS design to mitigate associated exposures. Further research is needed to analyze other unconfirmed features and possibly identify new features using different column separation and ionization methods.
Citation
Yan B, Zagorevski D, Ilievski V, et al. Identification of newly formed toxic chemicals in E-cigarette aerosols with Orbitrap mass spectrometry and implications on E-cigarette control. European journal of mass spectrometry (Chichester, England). 2021;27(2-4):141-148. doi:10.1177/14690667211040207
