Chen Cai, Pankow James F
Department of Chemistry, Portland State University, Portland, Oregon 97207, USA.
J Agric Food Chem. 2009 Apr 8;57(7):2678-90. doi: 10.1021/jf803018x.
Gas/particle (G/P) partitioning constant (Kp) values are reported for nicotine and ammonia for mainstream tobacco smoke (MTS) for a selection of cigarettes, "little cigars", and biddies. As K(p)(nic) decreases as a result of the increasing basicity in the MTS, there is an increase in volatility of nicotine from the smoke particulate matter. The "little cigars" and biddies exhibited generally lower K(p)(nic) values and higher unbound ammonia levels than most of the cigarettes, suggesting a correlation between the two parameters. However, within just the cigarettes, there was little correlation. The water content of MTS particulate matter was found to affect both K(p)(nic) and K(p)(amm). Unbound ammonia is actual NH3/NH4+; bound ammonia is comprised of compounds such as amides of ammonia; total ammonia is unbound + bound. Most historical studies of ammonia in MTS have not accurately measured either unbound or total ammonia: the acidic solutions historically employed to determine ammonia in MTS will release ammonia from bound forms by hydrolysis, and the release in those studies may not have been complete. This study concludes that a thorough examination of unbound and bound ammonia in MTS will be required before the role of ammonia in affecting volatility of nicotine in MTS can be understood.
报告了一系列香烟、“小雪茄”和比迪烟主流烟草烟雾（MTS）中尼古丁和氨的气/粒（G/P）分配常数（Kp）值。由于MTS中碱性增强，K(p)(nic)降低，尼古丁从烟雾颗粒物中的挥发性增加。“小雪茄”和比迪烟的K(p)(nic)值通常低于大多数香烟，未结合氨水平则高于大多数香烟，表明这两个参数之间存在相关性。然而，仅在香烟中，相关性很小。发现MTS颗粒物的含水量会影响K(p)(nic)和K(p)(amm)。未结合氨实际为NH3/NH4+；结合氨由氨的酰胺等化合物组成；总氨为未结合氨与结合氨之和。MTS中氨的大多数历史研究都没有准确测量未结合氨或总氨：历史上用于测定MTS中氨的酸性溶液会通过水解从结合形式中释放氨，而且那些研究中的释放可能并不完全。本研究得出结论，在了解氨在影响MTS中尼古丁挥发性方面的作用之前，需要对MTS中未结合氨和结合氨进行全面研究。
