液相色谱-串联质谱法测定蔬菜中甲基托布津和多菌灵

Determination of thiophanate-methyl and carbendazim in vegetables by liquid chromatography / tandem mass spectrometry

目的建立蔬菜中甲基托布津和多菌灵残留量的液相色谱-串联质谱检测方法。方法采用QuEChERS样品前处理技术,提取上清液用氮气吹干,加流动相溶解,液相色谱-串联质谱法测定。色谱柱采用Inertsil ODS-3柱(150 mm×2.1 mm,5μm),流动相为甲醇-水-乙酸(体积比为65∶35∶0.15)。采用电喷雾离子源正离子模式,选择反应监测方式,阴性样品基质加标外标法进行定量检测。结果甲基托布津和多菌灵标准溶液的浓度为5 ng/ml^500 ng/ml时,线性关系良好(r>0.997)。甲基托布津和多菌灵的定量检出限均为5μg/kg,添加水平为50μg/kg、200μg/kg的平均回收率为86.0%~95.0%,相对标准偏差(RSD)为6.5%~11.3%。结论本法简便、快速、准确,可用于检测蔬菜中的甲基托布津和多菌灵残留量。

Objective To develop a liquid chromatography-tandem mass spectrometry method for the determination of thiophanate-methyl and carbendazim residues in vegetables. Methods The analyte was extracted by QuEChERS method,the extractant was dried-up under nitrogen flow,and the residue was redissolved in mobile phase. Separation was performed on an Inertsil ODS-3 column（ 150 mm × 2. 1 mm,5 μm） using the isocratic mobile phase consisted of a mixture of methanol / water /formic acid（ 65∶35∶0. 15）. Detection was performed on a triple quadrupole tandem mass spectrometry with electrospray ionization source operating in positive ion mode. The matrix matched calibration curves were used for the quantification detection.Results When concentration of thiophanate-methyl and carbendazim was within 5 ng / ml-500 ng / ml,the linear relationship was good（ r 〉 0. 997）. The method had the quantification limit of 5 μg / kg. The mean recoveries ranged from 86. 0% to 95. 0%at the spiked level of 50 μg / kg,200 μg / kg,and the relative standard derivations（ RSDs） were within 6. 5%-11. 3%. Conclusion The method is quick,sensitive and specific,which is capable for the determination of thiophanate-methyl and carbendazim in vegetables.