Simultaneous determination of 118 pesticide residues in Chinese teas by gas chromatography-mass spectrometry

An efficient and sensitive method for simultaneous determination of 118 pesticide residues in teas has been established and validated. A multi-residue analysis of pesticides in tea involved extraction with ethyl acetate-hexane, clean-up using gel permeation chromatography (GPC) and solidphase extraction (SPE), and subsequent identification and quantification of the selected pesticides by gas chromatography-mass spectrometry (GC-MS). For most of the target analytes, optimized pretreatment processes led to no significant interference with analysis of sample matrix, and the determination of 118 compounds was achieved in about 60 min. In the linear range of each pesticide, the correlation coefficient was R ² ≥ 0.99. At the low, medium and high three fortification levels of 0.05-2.5 mg kg^-1, 118 pesticides average recoveries range from 61 % to 121 % and relative standard deviations (RSD) were in the range of 0.6-9.2 % for all analytes. The limits of detection for the method were 0.00030-0.36 mg kg^-1, depending on each pesticide.