气相色谱测定普洱茶中17种有机磷农药残留

Determination of 17 oganophosphorus pesticide residues in puer tea by gas chromatography

利用气相色谱(GC)建立了普洱茶中17种有机磷农药残留的测定方法。样品中农药残留2次用乙腈提取;弗罗里硅土层析柱净化中依次用30mL三氯甲烷-乙酸乙酯(9∶1,V/V)、30mL乙酸乙酯-甲醇(1∶1,V/V)作为洗脱剂,毛细管柱DB-17分离,火焰光度检测器FPD测定。结果表明,17种有机磷农药3个添加水平的平均回收率为67.23%～108.6%,相对标准偏差2.22%～9.86%。检出限为0.006～0.015mg/kg。该方法具有测定有机磷农药种类多、净化效果好、准确度和精密度高等优点,符合茶叶农药残留国内外检测标准。

The method for determination of 17 organophosphorus pesticide residues in puer tea was developed.The sample was extracted by acetonitrile with a homogenizer.The 17 oganophosphorus pesticide residues in puer tea were separated from each other through dual capillary columns DB- 17 and determined with dual flame photometric detectors（FPD）.Under above conditions,the average recoveries of 17 oganophophorus pesticides at spiked levels of 0.05-0.5mg/kg ranged from 62.23% to 108.6% ,and the relative standard deviations（RSD） were 2.22%-9.86%. The minimum detection limits were 0.006-0.015mg/kg.This method has the merits of good purifying effects, high accuracy and precision. It is accorded with pesticide residues testing standards in tea at home and abroad.