On the distribution of nicotine between the gas and particle phase and its measurement

A method is described which allows the separate sampling and analysis of gaseous and particulate nicotine with a denuder-filter combination. Recovery rates of 101.6 ± 3.6% are found for a denuder coated with benzenesulfonic acid. Particulate nicotine can be sampled with glass-fiber filters which are also impregnated with benzenesulfonic acid. The extracts of the denuders and filters are quantified by gas chromatography (GC/FID) after reextraction from 0.1 N NaOH into CH₂CI₂. A determination limit of 5 ng (abs.) is reached by use of n-hexadecane as an internal standard. This sampling system is interesting especially for the determination of semi-volatile compounds, such as nicotine, the distribution of which affects its efficiency in smoking. The different distribution of nicotine between the gas and particle phase in the presence of various additives was examined in model test systems. These may give evidence on the behavior of nicotine in cigarette smoke, whose effects may influence its distribution between main- and sidestream smoke. Gas-particle mixtures of nicotine are generated in different ways. The characterization of these mixtures is accomplished with physical methods for the measurement of particle concentration and size, and are verified by diffusive sampling and gas chromatographic analysis. It was found that for different test systems, nicotine-containing aerosol is only formed when the carrier particle is of an acidic nature and the nicotine is attached as a salt. In this way, the dispersion of aqueous potassium hydrogensulfate, citric, tartaric, or other organic acid solutions as submi-cron aerosols containing nicotine leads to a nicotine-containing aerosol. Also, phenol-containing aerosols can be formed under well-defined conditions. These aerosols as well as the distribution of nicotine are models of semi-volatile compounds with a distinct pH dependence for applications other than cigarette smoke as well.