Bull. Spec. CORESTA Congress, Lisbon, 2000, p. 159, ST15
Analysis of total ammonia in mainstream smoke
Philip Morris USA, R&D Operations Center, Richmond, VA, USA
Ammonia is generated in mainstream smoke (MS) from multiple precursors in tobacco such as amino acids, proteins, amino acid/sugar reactions and ammonia salts. Ammonia derived from both the particulate and vapor phases is measured with the particulate phase contributing greater than 80% of the total ammonia (µg/cig). The general approach used in the analytical methods involved the collection of MS using electrostatic precipitation or impingers with acidic solution combined with Cambridge filters (44 mm or 92mm) and the analysis of ammonium cation using ion chromatography with a conductivity detector. The available results from both internal testing and external literatures for 1R4F Kentucky reference cigarette, smoked under FTC puffing conditions, showed a wide range of yields from approximately 5 to 18 µg/cig. To investigate the possible causes for this wide range and to optimize the analytical method, several parameters deemed critical to the results were studied using 1R4F. They include types of acids (hydrochloric acid and sulfuric acid), acid strength (0.1N to 0.005N), trapping efficiency and sample stability. The effects of the acids and their strength on the total ammonia yields, stability and extraction efficiency will be discussed. The results from Kentucky reference cigarettes of different "tar" yields will be presented.