Dynamic microwave assisted extraction coupled with matrix solid phase dispersion for the determination of chiorfenapyr and abamectin in rice by LC-MS/MS

Chlorfenapyr and abamectin are two insecticides used commonly in rice-planting to control insects and mites. The residue remained in rice present potential health hazard to consumers. To realize the accurate determination of chlorfenapyr and abamectin in rice samples, a method based on dynamic microwave assisted extraction (DMAE) coupled with matrix solid phase dispersion (MSPD) was established and validated. In the proposed method, microwave energy was introduced into the elution process of MSPD and therefore improved the extraction efficiency. Different parameters affecting the extraction efficiency were studied and optimized, including type of dispersing sorbent, ratio of dispersing sorbent to sample, type of clean-up sorbents, microwave power, extraction solvent, volumes and flow rate of extraction solvent. Under optimal conditions, the interference in rice extract were removed effectively, moreover, the extraction and clean-up were combined in a single step and 15 samples were treated simultaneously with in 4 min. Low limits of detection (0.8 ng g(-1)) for chiorfenapyr and abamectin were obtained. The RSDs of intra- and inter-day were in the range of 2.6 to 8.1%. The recoveries of chlorfenapyr and abamectin from rice samples at spiking levels of 5, 50 and 100 ng g(-1) were 92.1-96.5% and 88.6-91.0%, respectively. Finally, the proposed method was successfully applied to analyze chlorfenapyr and abamectin in six rice samples, and satisfactory results were obtained. (C) 2017 Published by Elsevier B.V.