Ammonia enhances cigarettes' nicotine.

Three years ago, after intense congressional probing, the tobacco lobby released a hush-hush list of 599 additives that have been used in cigarettes (SN: 5/21/94, p. 330). Many substances on the list, such as carrots, figs, vanilla, dill seeds, and cocoa, were undoubtedly added to impart some characteristic flavor to the products. The function of others, such as ammonia, was less obvious--though the Food and Drug Administration had obtained tobacco industry documents suggesting that such high-pH substances might facilitate nicotine's addictiveness.

Now, researchers at the Oregon Graduate Institute in Portland have confirmed that suspicion. Their experiments show that ammonia helps turn the nicotine in smoke into gas, rendering the drug more available to the lungs.

Much of a cigarette's nicotine starts out in a fairly nonvolatile, acid form, notes environmental chemist James F. Pankow, who led the study. This acid also possesses an electric charge, which keeps the nicotine from moving easily through tissue and into blood. Ammonia converts the acid form of nicotine into a free base--an uncharged alkaline form that moves more freely into the air and tissue. Pankow likens this to treating cocaine with alkaline materials to create the more lipid-soluble, potent freebase cocaine known as crack.

In the August Environmental Science & Technology, Pankow's team shows that ammonia can increase nicotine's availability as a gas by 100 times.