Optimization of a multi-residue method for 101 pesticides in green tea leaves using gas chromatography–tandem mass spectrometry

AbstractA method for analysis of 101 pesticide residues in tea leaves was developed and validated for the first time. Pure acetonitrile was used as extraction solvent rather than acetonitrile after matrix hydration based on the amount of co-extracts and recoveries performance. During clean-up procedure, primary-secondary amine/graphitized carbon black (500mg) was selected, which exhibited outstanding properties in clean-up capabilities and recoveries of pesticides comparing to primary-secondary amine/graphitized carbon black (250mg), NH2-Carbon and TPT absorbents. The method was validated employing gas chromatography coupled to tandem mass spectrometry at the spiked concentration levels of 0.050 and 0.100mgkg−1. For most of the targeted pesticides, the percent recoveries range from 70 to 120%, with relative standard deviations