建立了测定蔬菜中四聚乙醛残留量的液相色谱串联质谱方法.蔬菜样品经乙腈提取,盐析后吹干乙腈提取液,再用氟罗里硅土固相萃取小柱净化,用正已烷/丙酮(80:20,V/V)混合溶剂洗脱,氮吹后用乙腈-20mmol/L,乙酸铵溶液(70:30,V/V)溶解后进行仪器分析.分析采用XBridgeTM C18色谱柱分离,乙腈-20mmol/L 乙酸铵溶液作为流动相洗脱,电喷雾正离子(ESI+)模式电离,多反应监测(MRM)模式检测,外标法定量.四聚乙醛在0.005～5.00 mg/L浓度范围内呈良好的线性,线性相关系数大于0.99;方法检出限为1.3μg/kg;定量限为4.0μg/kg.添加浓度为0.01,0.10,1.0和5.0 mg/kg时,平均回收率在73.0%～98.0%之间;批内和批间相对标准偏差均小于15%.%A method was developed for determining residual metaldehyde in vegetable by liquid chromatography with tandem mass spectrometry. The samples were extracted with acetonitrile. Then the extract was dried under nitrogen after salting-out. Further cleanup was performed on a florisil cartridge. The elution was dried under nitrogen and residues were dissolved in acetonitrile/20 mmol/L ammonium acetate solution (70/30, V/V ). The samples were analyzed by LC-MS/MS on a XBridgeTM C18 column with a mixture of acetonitrile and 20 mmol/L ammonium acetate solution as the mobile phase. The samples were quantified with the external standard calibration curve method. Good linearity was obtained for metaldehyde at the concentration of 0. 005-2. 50 mg/L with a 1inear relative coefficient more than 0. 99. The recoveries of metaldehyde in three kinds of vegetables were 73. 0 ％- 98. 0 ％ at the fortified levels of 0. 01-5.0 mg/kg with a limit of detection of 0. 0013 mg/kg and a limit of quantitation of 0. 004 mg/kg. The relative standard deviations were less than 15.0％.
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