Abstract: In order to investigate the removal efficiency of filter to tobacco-specific nitrosamines(TSNAs),the TSNAs in cigarette smoke,NNN,NAT,NNK and NAB,captured by the filters of 30 cigarette samples were determined by liquid chromatography and tandem mass spectrometry(LC-MS/MS).The filters were cut off the butts after smoking and extracted with 0.1 mol/L ammonium acetate aqueous solution.The resultant extraction passed through an OASIS MCX column,eluted with 50%(v/v) methanol,and analyzed by LC-MS/MS directly.The analytical conditions were:chromatographic column,Waters Symmetry Shield TM RP₁₈,column temperature 65℃,mobile phase,50% of methanol-water(containing 0.1% acetic acid) solution at the flow rate of 0.25 mL/min and isogradient elution mode.The results showed that:1) the recoveries of NNN,NAT,NNK and NAB were from 96.0% to 103.5% with the relative standard deviations(RSD) of less than 8% and the limits of detection of 0.7,0.3,0.6 and 0.4 ng/cig.,respectively;2) the removal efficiencies of filters to NNN,NNK,NAT and NAB were 16.67% to 43.05%,30.51% to 55.97%,16.19% to 45.00%,and 41.68% to 49.08%,respectively;3) the NNN and NAT removal efficiencies of the filters attached to blended type cigarettes were higher than those of the filters attached to Virginia type cigarettes,while the NNK,NAB and total TSNAs removal efficiencies of the filters of the two cigarette types were similar;4) the NNN and NAT removal efficiencies of cellulose acetate filter were higher than those of polypropylene filter,while NNK and NAB removal efficiencies of the two filters were similar.