Toward Better Characterization of a Free-Base Nicotine Fraction in e-Liquids and aerosols.

Introduction:
This text discusses a study that aimed to compare and evaluate different methods for estimating the free-base nicotine fraction (αfb) in e-cigarette liquids and aerosols. The study also examined the impact of e-cigarette devices on αfb.

Key Points:

* The study compared three methods for estimating αfb: ph measurement, liquid-liquid extraction (LLE), and molar ratio calculation.
* The study found that ph measurement is a simple and quick method, but it may not be easily automated. The dilution factor for this method was fixed at 10, as no effect of dilution was noted.
* LLE relies on the specificity of organic solvent for free-base nicotine extraction, but this may cause discrepancies in results. The molar ratio calculation method was found to be the most robust and versatile.
* The study found that αfb accounted for less than 5% of nicotine content regardless of experimental conditions. αfb was consistent between e-liquids and aerosols, regardless of e-cigarette devices.
* The study suggests that e-liquids are adequate surrogates for aerosols, which could facilitate the establishment of regulations.

Main Message:
The study provides valuable information on the most accurate and practical methods for estimating αfb in e-cigarette liquids and aerosols. The findings suggest that e-liquids can be used as surrogates for aerosols, which could simplify the implementation of regulatory policies. The study also highlights the importance of considering the impact of e-cigarette devices on αfb. Overall, the study provides a solid foundation for the development of appropriate quality control measures for e-cigarettes.

Bourgart E, Leclerc L, Pourchez J, Sleiman M. Toward Better Characterization of a Free-Base Nicotine Fraction in e-Liquids and aerosols. Chemical research in toxicology. 2022;35(7):1234-1243. doi:10.1021/acs.chemrestox.2c00041