Summary
Introduction:
This text describes a study that presents a method for determining the fraction of free-base nicotine (αfb) in electronic cigarette liquids (e-liquids) using headspace solid-phase microextraction (h-SPME) and gas chromatography-mass spectrometry. The study also verifies the method using lab-prepared e-liquid solutions with known αfb values and measures the αfb values for 18 commercial e-liquids.
Key Points:
* The study presents a method for determining the fraction of free-base nicotine (αfb) in e-liquids using h-SPME and gas chromatography-mass spectrometry.
* The method was verified using lab-prepared e-liquid solutions with known αfb values.
* The method was used to determine the αfb values for 18 commercial e-liquids.
* The αfb values ranged from 0.0 to 1.0.
* Increasing measurement error with decreasing αfb caused modestly lower method precision at small αfb.
* adding a liquid organic base may be more convenient than adding gaseous ammonia.
* The study also compares the αfb values obtained using h-SPME with those obtained using the 1h NMR method and diluted solution methods (DSMs) and native solution methods (NSMs).
Main Message:
The study presents a reliable and accurate method for determining αfb values in e-liquids using h-SPME and gas chromatography-mass spectrometry. The method is easily automatable, especially if an LB is used. The study also highlights the importance of considering the protonation state of nicotine in e-liquids, as it can affect the inhalation harshness during vaping. The study's findings can have implications for the regulation of e-cigarettes and their impact on public health.
Citation
Pankow JF, Luo W, McWhirter KJ, Motti CS, Watson Ch. Measurement of the Free-Base Nicotine Fraction (αfb) in Electronic Cigarette Liquids by headspace Solid-Phase Microextraction. Chemical research in toxicology. 2021;34(10):2227-2233. doi:10.1021/acs.chemrestox.1c00285
