Free-Base Nicotine is Nearly Absent in Aerosol From IQOS Heat-Not-Burn Devices, as Determined by 1H NMR Spectroscopy

Heat-not-burn products, e.g. IQOS, are becoming popular as alternative tobacco products. The nicotine protonation state in aerosols has addiction implications due to differences in absorption kinetics and harshness. The nicotine free-base fraction (αfb) ranges from 0-1. Herein we report αfb for IQOS aerosols using exchange-average 1H NMR chemical shift of the nicotine methyl protons in the bulk aerosol. This was verified by HS-SPME-GCMS, with total nicotine delivery quantified by HPLC-UV. αfb ≈ 0 for all products tested, lower than JUUL; likely a result of proton transfer from acetic acid and/or other additives in the largely aqueous aerosol. Others have reported higher αfb values (0.057) for these products, however, their methods were subject to error due to solvent perturbation effects. The αfb values presented herein were generated using an 1H NMR method that avoids this issue.