Determination of four carcinogens in mainstream cigarette smoke by liquid chromatography-tandem mass spectrometry

N-nitrosonornicotine (NNN), 4-(methylnitrosamino) -l-(3-pyridyl) -1-butanone (NNK), N-nitrosoanatabine (NAT) and N-nitrosoanabasine (NAB) are the most abundant carcinogens identified in tobacco and tobacco smoke. The accurate quantifications of NNN, NNK, NAT and NAB are necessary to evaluate its impact on the public health. A liquid chromatography-electrospray tandem mass spectrometry (LC-ESI MS/MS) method was developed to simultaneously determine NNN, NNK, NAT and NAB in mainstream cigarette smoke. Mainstream smoke was collected in a Cambridge filter pad and then was extracted by 10 mL 100 mmol/L ammonium acetate after 100 mu L of mixed deuterated internal standards was added. Then the extract was detected by using positive electrospray ionization on a tandem mass spectrometer in multiple reaction monitoring (MRM) mode. NNN, NNK, NAT and NAB were separated on a Zorbax Eclipse XDB-C18 column with the gradient elution using mobile phase A (0.1% acetic acid in water) and mobile phase B (0.1% acetic acid in methanol). The detection limits for NNN, NNK, NAT and NAB were 0.019, 0.002, 0.008 and 0.007 mu g/L, respectively. The recoveries were varied from 84.9% to 104.5% for Chinese Virginia cigarettes and the relative standard deviations (n =8) ranged from 2.96% to 6.65%. This proposed approach, which provides a higher sensitivity and specificity, is suitable for the determination of NNN, NNK, NAT and NAB in mainstream cigarette smoke.