Abstract: A multi-residue method for the determination of 88 pesticides in tea using gas chromatography-tandem mass spectrometry (GC-MS/MS) was developed. The target compounds were extracted with acetonitrile by accelerated solvent extraction (ASE), and the extracts were cleaned up by solid phase extraction (SPE) with a Carbon/NH2 cartridge and eluted with acetonitrile-toluene (3:1, v/v) before the identification and quantification of the residues by GC-MS/MS. Performance characteristics, such as accuracy, precision, linear range, limits of detection (LODs) and limits of quantification (LOQs), for each pesticide were determined. At low concentration level spiked (6.4 μg/kg), the average recoveries were in the range of 70%~100% for 87.5% analytes and the relative standard deviations (RSDs) were lower than 15% for 87.5% analytes. The quantification of analytes was carried out using the most sensitive transition for every compound and by matrix-matched standards calibration. The LOQs (S/N=10) were less than 10 μg/kg for 86.4% analytes. The method is sensitive, accurate, reliable and suitable for the simultaneous determination of multi-residue pesticides in green tea, Woolong tea, black tea and Puer tea.

Key words: multi-residue pesticides, tea, gas chromatography-tandem mass spectrometry (GC-MS/MS)