QuEChERS-超高效液相色谱-串联质谱法同时测定草莓中甲基硫菌灵、多菌灵和乙嘧酚残留

建立了QuEChERS-超高效液相色谱-串联质谱同时检测草莓中甲基硫菌灵、多菌灵和乙嘧酚残留的方法。样品经0.5%甲酸-乙腈提取，QuEChERS方法净化，以Agilent XDB-C18色谱柱(2.1 mm×150 mm，3.5 μm)进行UPLC分离，采用三重四极杆串联质谱以正离子多反应监测模式(MRM)进行测定。结果表明:在20~1 000 μg/L范围内，甲基硫菌灵、多菌灵及乙嘧酚的质量浓度与其相应的峰面积间呈现良好的线性关系，相关系数均大于0.997 8。在50~500 μg/kg添加水平下，草莓中甲基硫菌灵、多菌灵和乙嘧酚的平均回收率在86%~109%之间，相对标准偏差(RSD)在1.9%~13%(n=5)之间，检出限分别为2.5、0.50和1.0 μg/kg，定量限均为50 μg/kg。该方法样品前处理过程简单快速，分析时间短，灵敏度、准确度及精密度均符合农药残留检测要求，适用于草莓中甲基硫菌灵、多菌灵和乙嘧酚残留的检测。

Determination of thiophanate-methyl, carbendazim and ethirimol in strawberry using QuEChERS-ultra performance liquid chromatography-tandem mass spectrometry

A reliable QuEChERS-ultra performance liquid chromatography-tandem mass spectrometry analysis method was developed for residual simultaneous determination of thiophanate-methyl, carbendazim and ethirimol in strawberry (Fragaria ananassa Duchesne) in this study. The samples were extracted. by 0.5% formic acid-acetonitrile, cleaned up by the optimized QuEChERS method, and separated by UPLC with an Agilent XDB-C18 column (2.1 mm×150 mm, 3.5 μm). Targeted compounds were analyzed using UPLC-MS/MS in multiple reaction monitoring (MRM) mode via positive electrospray ionization. When the concentrations ranged from 20 to 1 000 μg/L, good correlation coefficients (r> 0.997 8) were achieved in the case of thiophanate-methyl, carbendazim and ethirimol. The average recoveries of the three pesticides ranged from 86% to 109% with the spiked concentration of 50~500 μg/kg and the relative standard deviation ranged from 1.9% to 13% (n=5). The detection limits were 2.5, 0.50 and 1.0 μg/kg, respectively. The quantitation limits were all 50 μg/kg for the three pesticides. This method is simple, rapid and time-saving. As the sensitivity, accuracy and precision are so satisfied with the requirements of the pesticide residue analysis that it can be applied to the analysis of thiophanate-methyl, carbendazim and ethirimol in strawberry.