Identification and occurrence of two new N-nitrosamino acids in tobacco products: 3-(N-nitroso-N-methylamino)propionic acid and 4-(N-nitroso-N-methylamino)butyric acid.

Two new N-nitrosamino acids, 3-(N-nitroso-N-methylamino)propionic acid (CAS: 10478-42-9) and 4-(N-nitroso-N-methylamino)butyric acid (CAS: 61445-55-4) were isolated and identified for the first time in various types of tobacco, including snuff, chewing and pipe tobacco, cigars and cigarettes. Their levels ranged from 0.15 to 7.4 and 0 to 2.2 mg/kg of dry weight tobacco, respectively. For comparison, amounts of other N-nitrosamino acids like N-nitrosoproline (NPRO) and tobacco-specific-nitrosamines (TSNA) were determined in the same samples. The levels of N-nitrosamino acids were highly correlated with the levels of TSNA.