Rapid determination of pesticide multiresidues in panax ginseng by QuEChERS-gas chromatography-mass spectrometry

In this study, the extraction and purification improvements of the QuEChERS method were coupled with gas chromatography-mass spectrometry ( GC-MS) to determine 20 pesticides in panax ginseng. Dry ginseng powder was mixed with water, and the solution was then extracted with acetonitrile and purified with N-propylethylenediamine ( PSA) and MgSO4 to remove co-extractives that might interfere with the results. The target compounds were detected after electron-impact ionization in selected ion monitoring ( SIM) mode. Under optimum conditions , the method gave a good linear relationship for the determination of the pesticides within a certain concentration range , with correlation coefficients greater than 0.990. Moreover, the limits of detection (S/N= 3) were 0. 002-0. 007 mg/kg, the limits of quantification (S/N= 10) were 0. 002-0. 024 mg/kg, and the average recoveries for pesticides in panax ginseng were 70. 41% -114. 06%, with relative standard deviations of 0. 76% -15. 47%. In comparison with previous methods, the new procedure has the advantages of simple sample preparation and higher sensitivity.