A liquid chsomatographic-tandem mass spectrometric method was used to simultaneously determine four tobacco-specific nitrosamines in cigarette mainstream smoke.Cigarette smoke particulate,obtained under standardized machine smoking,was collected on a Cambridge filter pad.The particulate was co-extracted with citric acid-phosphate buffer and cyclohexane and further purified by solid-phase extraction.Analyte identification and quantification were performed using multiple reaction monitoring with one precursor ion and two product ions as identifiers and electrospray ionization in positive mode.The limits of detection were in the range of 0.05～0.24ng/mL using an injection volume of 20μL,linear range over 2.5～1000ng/mL,linear correlation coefficients above 0.998,and recoveries 90.2%～95.1%.
