A Comparison between the Rate of Reaction of Nitric Oxide in the Gas Phase and in Whole Cigarette Smoke

There remains uncertainty about the rate of oxidation of nitric oxide (NO) in cigarette smoke. Using a single-port smoking machine and a chemiluminescence NO analyser we have investigated the rate of NO disappearance during cigarette smoke ageing over 10 minutes for gas phase and whole smoke. The disappearance of NO in whole smoke conformed to the (pseudo) second order kinetics observed for oxidation of NO in air. In the gas phase however the rate of disappearance was more rapid and appeared to follow first order kinetics. The possible mechanisms for this difference in behaviour are discussed.