Simultaneous determination of five organophosphorus pesticide residues in cucumber by LC-MS/MS | 液相色谱-串联质谱法检测黄瓜中5种有机磷农药残留

Chinese. 建立液相色谱-串联质谱（LC-MS/MS）同时检测黄瓜中敌百虫、乐果、敌敌畏、杀螟硫磷、毒死蜱5种有机磷农药残留的方法。样品经过丙酮提取,弗罗里硅土净化,以甲醇-水（水相含0.1%甲酸）为流动相梯度洗脱,采用ZORBAX SB-C18（5μm×2.1 mm×150 mm）色谱柱分离,电喷雾离子化正模式（ESI＋）离子化,多反应监测模式（MRM）下测定。结果显示：方法标准曲线线性良好,R2≥0.998;乐果与敌敌畏的定量限为0.002 mg.kg-1,敌百虫、杀螟硫磷和毒死蜱的定量限为0.01mg.kg-1;回收率为72%～98%,相对标准偏差（RSD）≤3.6%。表明：该方法可实现对5种有机磷农药的同时快速测定,目标农药的响应值高,检测限低,能够为生食蔬菜风险评估研究提供准确有效的数据支持。

English. A method to identify and quantify five organophosphorus pesticides about trichlorfon,dimethoate,dichlorvos,fenitrothion and chlorpyrifos in cucumber was developed using the liquid chromatography-tandem triple quadrupole mass spectrometric（LC-MS/MS）.The sample was extracted by acetone and cleaned up with florisil.The separation was performed on a ZORBAX SB-C18（5 μm×2.1 mm×150 mm）with the gradient elution of methanol-water with 0.1% formic acid（volume ratio）as mobile phase.Sample was detected by multiple reaction monitoring（MRM）with electric spray ionization（positive）.The result showed that satisfactory linear results have been got with R2≥0.998.The limit of quantity（LOQ）of dimethoate and dichlorvos was 0.002 mg・kg-1,and the limit of quantitaty（LOQ）of trichlorfon,fenitrothin and chlorpyrifos was 0.01 mg・kg-1,depending on the matrices and spiked concentration,ranging from 72% to 98% with relative standard deviations（RSD）≤3.6%.This simple,rapid and sensitive method can be applied to supplying reliable data for the study of the risk assessment of raw vegetables.