液相色谱串联质谱法测定蔬菜中四聚乙醛残留量

Determination of Metaldehyde Residues in Vegetable by Liquid Chromatography with Tandem Mass Spectrometry

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-20 mmol/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-20 mmol/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4.0!g/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 linear 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%.