Abstract
Heat-not-burn products, eg, I quit ordinary smoking (IQOS), are becoming popular alternative tobacco products. The nicotine aerosol protonation state has addiction implications due to differences in absorption kinetics and harshness. Nicotine free-base fraction (α(fb)) ranges from 0 to 1. Herein, we report α(fb) for IQOS aerosols by exchange-averaged (1)H NMR chemical shifts of the nicotine methyl protons in bulk aerosol and verified by headspace-solid phase microextraction-gas chromatography-mass spectrometry. The α(fb) ≈ 0 for products tested; likely a result of proton transfer from acetic acid and/or other additives in the largely aqueous aerosol. Others reported higher α(fb) for these products, however, their methods were subject to error due to solvent perturbation.