Simultaneous determination of three pesticides and their metabolites in unprocessed foods using ultraperformance liquid chromatography-tandem mass spectrometry.

We have developed a rapid, multi-compound analytical method for measuring residues of the pesticides thiamethoxam and its metabolite, clothianidin; fipronil and its three metabolites, fipronil sulfone, fipronil sulfide, and fipronil desulfinyl; and pyraclostrobin in unprocessed foods (rice, corn, cucumbers, tomatoes, apples, and bananas) by ultra-performance liquid chromatography coupled to tandem mass spectrometry. Acetonitrile was used as the extraction solvent, and an octadecylsilane-dispersive SPE was used to clean up the analytes, which were then separated through a UPLC HSS T3 column connected to a tandem mass spectrometer via an electrospray ionisation source. The linearity of this method for the target analytes was excellent (R2 ≥0.990) in the concentration range of 5–1000 μg kg–1. The average recoveries of the seven compounds at concentrations of 10, 100, and 1000 μg kg–1from six spiked matrix samples ranged from 73.6 to 110.6%, all with RSD values of ≤19.7%. The limit of quantification was 10 μg kg–1. The method validated the effectiveness of the method for routine monitoring the residue of these pesticides and their metabolites in foods. [ABSTRACT FROM PUBLISHER]