Table 2

Values of K oa, 1 (40°C) for benzoic acid and vanillin in e-liquid formulations.

C HA/CNic α fb K oa,1 Log K oa,1
Benzoic acid
 JUUL ‘Cool Mint’ (5% nicotine)0.97*0.13581.77
 JUUL ‘Classic Menthol’ (5% nicotine)0.98*0.13531.72
 JUUL ‘Crème Brûlée’ (5% nicotine)0.97*0.12721.86
 JUUL ‘Fruit Medley’ (5% nicotine)0.99*0.12591.77
 JUUL ‘Cool Cucumber’ (5% nicotine)1.00*0.11651.82
 JUUL ‘Classic Tobacco’ (5% nicotine)1.00*0.11651.82
 JUUL ‘Virginia Tobacco’ (5% nicotine)1.00*0.11651.82
 JUUL “Mango” (5% nicotine)0.99*0.091152.06
 JUUL “Virginia Tobacco” (3% nicotine)0.94*0.14661.82
 JUUL ‘Mint’ (3% nicotine)1.04*0.11481.68
  Averages for JUUL0.99±0.03 SD0.12±0.0167±181.81±0.10
 43/57 PG/GL (by wt.)+nicotine+benzoic acid (final nicotine level=4.6 wt%)1.010.16261.41
 32/68 PG/GL (by wt.)+nicotine+benzoic acid (final nicotine level=4.6 wt%)1.030.14311.49
 32/68 PG/GL (by wt.)+nicotine+benzoic acid+5% (by vol.) water (final nicotine level=4.5 wt%)1.030.11511.71
 45/55 PG/GL (by wt.)+nicotine+vanillin
 (final nicotine level=5.1%)
 45/55 PG/GL (by wt.)+nicotine+vanillin
 (final nicotine level=5.1%)
 45/55 PG/GL (by wt.)+nicotine+vanillin
 (final nicotine level=4.9%)
  Averages for vanillinAve.±1 SD0.0089±0.0025−2.07±0.13
  • *By liquid chromatography for both nicotine and benzoic acid, using a method discussed elsewhere.15

  • ave, average; C HA, total molar-based concentrations of HA; C Nic, total molar-based concentrations of nicotine; α fb, fraction of nicotine in the free-base form; GL, glycerol; PG, propylene glycol; vol., volume; wt., weight.