Analysis of tobacco-specific N-nitrosamines in indoor air

A method was developed and applied for the assessment of tobacco-specific N-nitrosamines (TSNA) in indoor air polluted with tobacco smoke. Air samples were collected on Cambridge filters treated with 0.01 M potassium bisulfate, extracted with dichloromethane and enriched by column chromatography. The fraction containing the TSNA was concentrated and placed on a thermal desorption cartridge packed with Tenax GR. The sample was thermally desorbed and analyzed by capillary GC using a thermal energy analyzer. When the method was applied in a test laboratory in which one, two and four cigarettes were smoked during 30 min, linearity was observed. Field studies included sampling in bars, restaurants and trains. The concentration of N′-nitrosonornicotine (NNN) ranged from not detected to 23 pg/l, that of N′-nitrosoanata-bine ranged from not detected to 9 pg/l, while 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) was detected in concentrations ranging from 1 to 29 pg/l. This means an exposure to NNN and NNK of 0.1−0.3 cigarette equivalents. Thus, non-smokers can be exposed to highly carcinogenic TSNA.