Abstract: A high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was established for the determination of spinosyn A and D in foodstuffs．The residues in food were extracted with acetonitrile-water(50:50, v/v)，and purified by a HLB SPE column. The mass spectrometry was operated with electrospray in positive ionization mode and spinosyn A and D were identified in multiple reaction monitoring (MRM)mode. The fragmentation pathways for the main product ions were analyzed．No significant matrix effect was found for spiked samples．The recoveries of spinosyn A and D spiked in food were 76.2%-114.0% at spiked levels of 1-10μg/kg．The relative standard deviations (RSDs) were less than 10%．The limits of quantitation (LOQs) were 0.5μg/kg for spinosyn A, 1.0μg/kg for spinosyn D．This method is sensitive and accurate in the determination of spinosyn A and D in foodstuffs．

Key words: (HPLC-MS/MS), food, residue, spinosyn A and D