Organohalogen and Organophosphorous Pesticide Method for Ginseng Root — A Comparison of Gas Chromatography-Single Quadrupole Mass Spectrometry with High Resolution Time-of-Flight Mass Spectrometry

Abstract

A method has been developed for the analysis of 170 organohalogen and organophosphorous pesticides, isomers, and metabolites in dried ground ginseng root. Pesticides were extracted with ethyl acetate and purified with gel permeation chromatography (GPC) and primary/secondary amine modified silica (PSA)/graphitized carbon black (GCB) combination SPE column. Each purified pesticide extract was determined by both gas chromatography single quadrupole mass spectrometry using selected ion monitoring (GC-qMS-SIM) and by gas chromatography high resolution time-of-flight mass spectrometry (GC-HR-TOFMS). The geometric mean LOQs using the qMS and TOFMS were 4 and 3 ng/g ginseng, respectively. Mean recoveries from ginseng were 83, 79, and 75% with standard deviations of 4, 5, and 3%, respectively, for 25, 100, and 500 ng/g using GC-qMS-SIM. Mean recoveries using GC-HR-TOFMS were 93, 85, and 81% with mean standard deviations of 7, 7, and 8% for 25, 100, and 500 ng/g, respectively. Seven dried ginseng root products were found to contain combinations of the following pesticides: dacthal, diazinon, DDT, hexachlorobenzene, iprodione, lindane, procymidone, and quintozene (1-460 ng/g). No significant differences were found in the concentrations measured for these pesticides on commercial ginsengs using either of the two GC/MS techniques.