Determination of 32 Fungicide Residues in Tea by Gas Chromatography-Tandem Mass Spectrometry

A gas chromatography-tandem mass spectrometry (GC-MS/MS) method was developed for detecting 32 fungicide residues in teas.The samples were extracted by acetonitrile under high-speed homogenization, purified with PSA, GCB, C18, and determined by GC-MS/MS in multi-reaction ion monitoring mode. Pesticide contents were determined by using the standard curves constructed with solutions of respective external standards. Linearity of the curves for 27 pesticides ranged from 10 μg·L^-1 to 1 000 μg·L^-1, and from 20 μg·L^-1 to 1 000 μg·L^-1 for the remaining 5 pesticides, with correlation coefficients greater than 0.99. The limits of detection were 0.1-8.1 μg·L^-1 (S/N ≥ 3); and, those of quantification, 0.4-23.4 μg·L^-1 (S/N ≥ 10). The average recovery rates were 70.4%-109.1%; and RSD (n=6) 3.4%-10.3%. The newly developed highly sensitive methodology that required simple pre-treatment and effective purification procedures appeared to be appropriate for the detection of fungicide residues in teas.