Nitrosamine compounds are difficult to analyse quantitatively because they and their precursors are highly reactive. False-positive and false-negative results must always be eliminated before determination. When studying tobacco and mainstream smoke, formation, degradation and transnitrosation are often observed. This is particularly true during the processing and storage of sample solutions. The use of ascorbic and sulfamic acids on Cambridge filter and in aqueous solutions for the collection of mainstream smoke was tested. Without the use of a reducing agent an increase of between 70 and 250% in nitrosamines level was observed. This work shows that the use of sulfamic acid is essential to minimise the additional formation of nitrosamines after smoking. Using the improved method the author demonstrated how selected tobacco varieties can affect the formation of tobacco specific nitrosamines. The plant material was selected by the"Institut du Tabac de Bergerac (France)". Two varieties of isogenic tobacco were chosen which differ only in their specific aptitude to convert nicotine to nornicotine. A tobacco with a nornicotine content reduced by 89% has been found to have a tobacco nitrosonornicotine (NNN) content reduced by 72%. The NNN concentration of smoke produced from this tobacco, however, is reduced by 42%.