关键词: 茶叶, 农药残留, 分散固相萃取, 气相色谱-质谱法

Abstract:

A method to determine 47 pesticide residues in tea using QuEChERS and GC-MS was established. For the
extraction of pesticide residues, dry samples were vortex-mixed with 40 mg of NaCl dissolved in 2 mL of MeCN and
centrifuged (5000 r/min for 5 min). Then 1 mL aliquot of the supernatant was taken and vortex-mixed for 2 min after the
addition of 25 mg of PSA, 7.5 mg of GCB, 150 mg of MgSO4 and 40 mg of NaCl and entrifuged (5000 r/min for 5 min).
The resulting supernatant was injected in to a GC-MS for analysis of pesticide residues. Under the optimized conditions of
particle size and amount of samples, extraction solvent type and volume and mixing method and purificant, the recovery of
the method for spiked samples ranged from 81% to 102.2%, and precision from 6.5% to 18.3% (RSD). The linear range was
0.00195－1.0 mg/kg (R2 ＞ 0.97), limit of detection (LOD) 0.0009－0.0214 mg/kg, and limit of quantitation (LOQ) 0.0029－
0.0712 mg/kg. This method could substantially meet the “Uniform Limits” of Japan and the EU for analysis of pesticide
residues.

Key words: tea, pesticide residue, dispersive solid phase extraction, gas chromatography-mass spectrometry (GC-MS)