Abstract:An efficient and accurate analytical method was established for the determination of lactucin in lettuce by dispersive solid -phase extraction purification combined with ultra -high performance liquid chromatography-tandem mass spectrometry （UPLC-MS/MS）. The key pretreatment and analytical conditions，including chromatographic column type，extraction solvent and purification filler，were optimized to determine the optimal detection parameters. The results showed that the established method exhibited a good linear relationship in the concentration range of 1.0-250.0 μg/L，with a linear regression equation of y=8569.1x+231 and a correlation coefficient of0.9992. The limit of detection （LOD） was 1.0 μg/kg，and the limit of quantification （LOQ） was 3.0 μg/kg. The verification tests presented that the spiked recoveries ranged from 90.2% to 99.8%，and the relative standard deviations （RSD） were between 2.1% and 4.6%. The method possessed high sensitivity，excellent selectivity and stable recovery performance，which was suitable for the quantitative detection and quality control of lactucin in lettuce.