Study of Analytical Methods for Determining 16 Organophosphorus Pesticide Residues in Panax Notoginseng and Aucklandia Lappa Decne by Automated Solid-Phase Extraction System and GC/MS

A fast and sensitive multi-residue analytical method was developed for the determination of organophosphorus pesticide residues in Panax notoginseng and Aucklandia lappa decne by comparing an ultrasonic extraction and homogenate extraction approach coupled with automated solid-phase extraction system and gas chromatography-mass spectrometry (GC/MS). Various factors affecting the homogenate extraction and purification efficiency were investigated in detail. The optimum conditions for homogenate extraction of organophosphorus pesticide residues from Panax notoginseng and Aucklandia lappa decne were 60 mL dichloromethane, 10000 r/min of extracting revolution speed and 2 min of extracting time. The extracts were cleaned up by automated solid-phase extraction system and determined by GC/MS. Under the optimum conditions, the results of the homogenate extraction approach were compared with those of the ultrasonic extraction, and the homogenate extraction approach was used to extract the samples. The average recoveries of the method by a homogenate extraction approach coupled with automated solid-phase extraction system and GC/MS ranged from 72.56% to 96.70%, and RSDs were 0.05~0.14%, which allowed the determination of 16 organophosphorus pesticide residues in Panax notoginseng and Aucklandia lappa decne. The results indicated that the proposed method can apply for the determination of organophosphate pesticides residues in Panax notoginseng and Aucklandia lappa decne with high accuracy and precision.