气相色谱法测定茶叶中的噻嗪酮、甲胺磷、乙酰甲胺磷及三唑磷残留

 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10 min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7.0~12.0 μg/kg。

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

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 degrees C. 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 (3sigma) in the tea samples were about 7.0-12.0 microg/kg.