Determination of Unprotonated Ammonia in Whole Cigarette Smoke

The total ammonia content of smoke is essentially ammonium salts with insignificant amounts of free ammonia. An ammonia electrode was used to experimentally measure the amount of free ammonia in the smoke of several cigarettes and two little cigars. For comparison, the theoretical amount of free ammonia was calculated from the total ammonia content and smoke pH. Free ammonia in domestic filter and non-filter cigarettes ranged from 1 to 4 ng with totaI ammonia contents of 28 to 44 µg. The smoke from a dark tobacco cigarette and Iittle cigar contained 1.2 and 2.4 µg of free NH₃, respectively. These two smoking items had total ammonia contents of 147 and 310 µg, respectively. The calculated free ammonia agreed with the experimentaI values. No significant errors were introduced by the presence of methylamine in the smoke in either total ammonia or free ammonia results.