Multiresidue method for the determination of pesticides in Oolong tea using QuEChERS by gas chromatography-triple quadrupole tandem mass spectrometry.

We propose a simple, rapid analytical method for determination of 89 pesticides in Oolong tea by GC/MS/MS. Samples were extracted via QuEChERS. The limits of detection and quantification range of the 89 pesticides were 1-25μgL-1 and 10-50μgL-1, respectively. Good separation was attained in less than 36min. A wide linear range of 1-250μgL-1 was observed with r2 values from 0.9955 to 0.9998. Pesticide-free tea powder spiked at 50 and 100μgL-1. Recovery ranges of the 86 (50μgL-1) and 83 (100μgL-1) pesticides were from 60% to 120%. Relative standard deviations were less than 20%. The laboratory proficiency test (FAPAS, 2014) shows satisfactory (|z|<2) z-score values. The proposed monitoring technique rapidly and efficiently screens, multiple pesticides in Oolong tea.