Conversion of Nicotine in Tobacco Smoke to Its Volatile and Available Free-Base Form through the Action of Gaseous Ammonia

Abstract

Ammonia-forming compounds are routinely added to cigarette tobacco. The U.S. Food and Drug Administration (FDA) has argued that this is done to promote the formation of the volatile free-base form of nicotine in mainstream smoke (MSS) particles, thus increasing its availability to the smoker. The presence of ammonia in tobacco smoke may also be expected to promote the volatilization of nicotine from environmental tobacco smoke (ETS) particles in indoor air. The gas/particle partitioning of nicotine can be parameterized in terms of the gas/particle partitioning constant Kp = cp/cg, where cp (ng/μg) is the concentration in the particle phase and cg (ng/m3) is the concentration in the gas phase. The ability of ammonia to increase the amount of nicotine in the gas phase, as compared to the particle phase, was measured and confirmed. A gas-phase am monia pressure of pNH3 of ∼100 × 10-6 atm (100 ppmV) was found to reduce the Kp value for the partitioning of nicotine to tobacco smoke particulate matter by more t...