Abstract: An improved method to screen 52 pesticide residues in flavored tea using QuEChERS coupled with liquid chromatography-quadrupole-time-of-flight mass spectrometry (LC-Q-TOF-MS) has been investigated. The flavored tea was extracted with acetonitrile and purified using by primary secondary amine (PSA), graphitized carbon black (GCB) and C₁₈ sorbent. The resultant residues were then analyzed using LC-Q-TOF-MS. The recoveries of all the pesticides in flavored tea at the four spiked levels of 10, 20, 50 and 100 μg/kg were 70%-120% and the relative standard deviations (RSDs, n=3) were less than 20%. The calibration curves of the 52 pesticide residues had good linear relationships, and the correlation coefficients were more than 0. 99. The screening detection limits (SDLs) and the limits of quantitation (LOQs) for the 52 pesticides were in the range of 0.001-0.01 mg/kg and 0.002-0.02 mg/kg, respectively, which were lower than maximum residue limits standard permitted by the European Union (EU). This method is simple, rapid, reliable, and can meet the requirements for the simultaneous determination of 52 pesticide residues in flavored tea.

Key words: flavored tea, liquid chromatography-quadrupole-time-of-flight mass spectrometry (LC-Q-TOF-MS), pesticide multi-residues, QuEChERS