Analysis the formation of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone in tobacco smoke generated from pyrolysis under inert and oxidative conditions respectively

•The contents of 4-(methylnitrosamino)-l-(3-pyridyl)-1-butanone in smoke (Air) were much higher than that in tobacco leaves and in smoke (N2).•Nicotine and active nitrogen oxides are principal precursors and reducing sugars could prohibit the formation of 4-(methylnitrosamino)-l-(3-pyridyl)-1-butanone in smoke.•The main reason for the difference of 4-(methylnitrosamino)-l-(3-pyridyl)-1-butanone formation in tobacco leaves and smoke is the source of active nitrogen oxides.

4-(methylnitrosamino)-l-(3-pyridyl)-1-butanone is an important and abundant strongly carcinogenic agent in tobacco leaves and its smoke, hence 15 kinds of tobacco samples were collected to study the formation of 4-(methylnitrosamino)-l-(3-pyridyl)-1-butanone in the tobacco smoke generated by pyrolysis under inert and oxidative conditions respectively. Contents of 4-(methylnitrosamino)-l-(3-pyridyl)-1-butanone in tobacco leaves and in the smoke were compared. The effects of nicotine, reducing sugar, O2, nitrate and nitrite salts on the release of 4-(methylnitrosamino)-l-(3-pyridyl)-1-butanone were also investigated. The results show that: 1) the contents of 4-(methylnitrosamino)-l-(3-pyridyl)-1-butanone in smoke under oxidative condition were much higher than that in tobacco leaves and in smoke under inert condition; 2) nicotine and active nitrogen oxides are principal precursors and reducing sugars could prohibit the formation of 4-(methylnitrosamino)-l-(3-pyridyl)-1-butanone in smoke; 3) nitrate and nitrite salts can give rise to the release of 4-(methylnitrosamino)-l-(3-pyridyl)-1-butanone in smoke (Air) dramatically, but nitrite showed less effective than nitrate; 4) O2 not only can react with nitrate and nitrite salts to decompose active nitrogen oxides, but also can react with the nitrogen-containing compounds in tobacco leaves at high temperatures, which provided more active nitrogen oxides combined with nicotine to produce 4-(methylnitrosamino)-l-(3-pyridyl)-1-butanone.