Determination of 28 pesticide residues in fresh tea leaves using QuEChERS-gas chromatography-tandem mass spectrometry

A multiresidue analytical method for the determination of 28 pesticide residues in fresh tea leaves was developed and evaluated by using QuEChERS (quick, easy, cheap, effective, rugged and safe) and triple-quadrupole tandem mass spectrometry (GC-MS/MS). Samples were extracted by acetonitrile, and purified by 75 mg PSA, 25 mg C18 and 4 mg GCB, followed by GC-MS/MS detection under multi-reaction monitoring (MRM) mode and quantified by external standard method. Good linearity was achieved between area size and concentration from 0.020 to 0.40 mg/L, with a coefficient of determination higher than 0.991. The average recovery at different spiking levels (0.10, 0.50 μg/kg) was ranged from 77% to 106% with RSD (relative standard deviation, n = 6) 1.4%-8.0%. The LOD (limit of detection) was 5.0-20 μg/kg, and LOQ (the limit of quantification) was 10-60 μg/kg. The method was simple, quick, accurate, highly sensitive and suitable for the simultaneous analysis of multi-residues of pesticides in fresh tea leaves.