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.