Rapid determination of 56 pesticide residues in Dendrobium officinale by MPFC-QuEChERS method combined with ultra-performance liquid chromatography-tandem mass spectrometry

Objective: In order to analyze the risk of pesticide residues in D. officinale, a method for rapid determination of 56 pesticide residues in D. officinale by a kind of ultrafiltration purification column（MPFC-QuEChERS） combined with ultra-performance liquid chromatography-tandem mass spectrometry（UHPLC-MS/MS）was developed. Methods: The samples were extracted with acetonitrile contained 0.1% formic acid, salted out, shaken, centrifuged, and single-step purified by a MPFC-QuEChERS purification column. Mass spectrometer was operated in the positive and negative ion mode using select reaction monitoring for qualitative and quantitative analysis. Results: The result showed that, the 56 kinds of pesticides showed good linearity when they were in 1.0~250.0 μg/L （R2＞0.99）. The limits of detection （LOD） was 1~5 μg/kg. Three levels of 1, 2 and 10 times of LOQ were added to the sample, the average recovery of each substance in D. officinale was 75.1% to 107.0%, of which the RSDs were 2.7%~18.9%. Conclusion: This method was used to detect pesticide residues in 20 batches of D. officinale. The results showed that 6 kinds of pesticides were detected in 5 samples with the contents ranging from 0.066 7 mg/kg to 1.872 mg/kg. The method is simple, fast and efficient, and could be used for rapid screening and analysis of pesticide residues in D. officinale.