Abstract:

A gel permeation chromatographic method was developed for the extraction of 36 pesticides from mushroom prior to gas chromatography with a triple quadrupole mass spectrometric determination. The extraction was based on homogenization with ethyl acetate using a high speed homogenizer. A gel permeation chromatographic clean-up process with ethyl acetate-cyclohexane (1∶1, v/v) as mobile phase was applied to the extracts to separate the low-molecular mass pesticides from the high molecular mass compounds in the mushroom. The 7-15 min eluate fraction was collected for subsequent analysis. The target compounds were quantified in the final extract by gas chromatography using a triple quadrupole mass spectrometer with multiple reaction monitoring (MRM). In the linear range (0.01-1.0 mg/L) of each pesticide, the correlation coefficient was higher than 0.99.The average recoveries (spiked at the levels of 0.01, 0.05, 0.10 mg/kg) were from 72.6% to 117.1% with the relative standard deviations from 2.0% to 10.8%(n=5). The limits of detection (LOD) for these pesticides were from0.1 to 0.7 μg/kg and the limits of quantification (LOQ) were from 0.2 to 2 μg/kg.

Key words: gas chromatography-tandem mass spectrometry (GC-MS/MS), mushroom , pesticides, residue determination, gel permeation chromatography (GPC)