Abstract: The method of determination of 47 pesticide residues in tea by using QuEChERS and GC-MS was established. The extraction mixture (2 mL MeCN, 40 mg NaCl) was vortex-shaken (2 min) with the dry tea sample (0.5 g, 20 mesh). After centrifugalized (5 000 r/min、5 min), the supernatant (1 mL) was vortex-shaken (2 min) with purificants (25 mg PSA, 7.5 mg GCB, 150 mg MgSO4, 40 mg NaCl). After centrifugalized (5 000 r/min, 5 min), the supernatant was injected into GC-MS, the sample data was acquired by SIM mode. In this paper, the size and amount of the samples, kind and volume of the extraction solvent, the mixed mode, and the amount of each purificants were optimized. The recoveries were > 81% in the concentration linearity range (0.00195~1.0 mg/kg, R2>0.97). The relative standard deviations (RSD) were 6.5~18.3%. The limit of determination (LOD) were 0.0009~0.0214 mg/kg; the limit of quantitation (LOQ) were 0.0029~0.0712 mg/kg, which were matched to the requests of the Uniform Limit of pesticide residues of Japan and EU, basically.

Key words: tea, pesticide residue, QuEChERS, gas chromatography-mass spectrometry (GC-MS)