Determination of Buprofezin, Methamidophos, Acephate, and Triazophos Residues in Chinese Tea Samples by Gas Chromatography

建立了同时测定茶叶中噻嗪酮、甲胺磷、乙酰甲胺磷和三唑磷4种农药残留量的测定方法。在45℃加温条件下,用乙酸乙酯 正己烷混合溶剂提取及活性炭色谱柱净化,用不同配比的乙酸乙酯 正己烷混合液梯度洗脱待测组分,以DB 210毛细管色谱柱分离、氮磷检测器测定。结果表明,上述4种农药在10min内能很好地分离;样品加标回收率(n=3)为73 4%～96 9%。方法的变异系数为2.49%～3.35%,茶叶(干重)中4种农药的定量检测下限为7 0～12 0μg/kg。A method has been developed for the simultaneous determination of buprofezin, methamidophos, acephate and triazophos residues in Chinese tea samples. The pesticide residues were extracted from tea samples with a mixture of ethyl acetate and n-hexane (50∶50, v/v) at 45 ℃. The extracts were subsequently treated with a column packed with 40 mg of active carbon by gradient elution with ethyl acetate and n-hexane. Buprofenzin and the three (organophosphorus) pesticides were analyzed by gas chromatography using a DB-210 capillary column and a nitrogen-phosphorus detector. The recoveries for spiked standards were 73.4%-96.9%. The relative standard deviations were all within 4.63%. The limits of quantitation (3σ) in the tea samples were about 7.0-12.0 μg/kg.福建省自然科学基金重点项目(B0220001)