Determination of Triazole Pesticides in Zizania Latifolia by GC-MS Combined with QuEChERS and Dispersive Liquid-Liquid Microextraction

The residues of myclobutanil, tebuconazole and difenoconazole in Zizania latifolia were extracted with a method of QuEChERS combined with dispersive liquid-liquid microextraction (DLLME), and then determined by GC-MS. The sample (3.000 g) was ultrasonically extracted with 3 mL of acetonitrile for 1 min, and the extract was cleaned up with a mixture of PSA (30 mg) and C₁₈ (30 mg). The purified solution (800 μL) was transferred to Pasteur pipette, and then 30 μL of toluene was added. After the solution was mixed well, 2.5 mL of water was injected quickly and the solution was treated with ultrasonic for 45 s and centrifugation. After dehydration with anhydrous sodium sulfate, the upper organic phase was separated on a DB-5MS capillary chromatographic column. EI and SIM were adopted in MS analysis. The linearity ranges of the 3 presticides were 5.0-500, 5.0-500, 12.5-1 250 μg·kg^-1 respectively, with detection limits of 1.4, 0.86, 3.0 μg·kg^-1 respectively. Recovery rates obtained by standard addition method were 82.7%-116%, and RSDs (n=5) were 4.1%-15%.