Multi-residue determination of 42 pesticides in tea by gas chromatography-mass spectrometry

A method for the determination of 42 pesticide(12 organochlorines,9 pyrethroids,20 organophosphorus compounds and tebuconazole) residues in tea by gas chromatography-mass spectrometry is described.Pesticides were extracted from tea with acetonitrile in an ultrasonic bath and purified on a graphitised carbon black column,and then determined by gas chromatography with electron ionization mass spectrometric detection in the selected ion monitoring mode.When the contamination level was in the range 0.01-0.8 mg/kg,the recoveries ranged from 62.5% to 120.1% with the relative standard deviation from 0.7% to 15.1% for the different pesticides.The detection limit of the method was estimated to be 0.0003-06.0092 mg/kg.The method was shown to be linear over the range assayed,0.004-20 mg/kg,with determination coefficients 0.992.