茶叶中9种农药残留的毛细管气相色谱法测定

Capillary gas chromatographic determination of nine pesticide residues in Chinese tea

建立了用毛细管气相色谱法同时测定茶叶中噻嗪酮、甲胺磷、乙酰甲胺磷、敌百虫、乐果、甲基对硫磷、水胺硫磷、三唑磷、伏杀硫磷等9种农药残留量的方法。待测农药残留组分在4 5℃加热条件下用乙酸乙酯-正己烷(1∶1,v v)混合溶剂提取,活性炭固相萃取柱(5mm×75mm ,活性炭约4 0mg)净化,乙酸乙酯-正己烷(6∶1,v v)混合液淋洗,HP - 5毛细管色谱柱(15m×0 .5 3mm ,1 5 μm)分离,氮磷检测器测定。9种农药残留组分能在11min内很好地分离。样品中添加待测农药标准,回收率为6 9.2 %～10 1.4 % ,方法变异系数4 .0 9%～16 .5 5 % (n =6 ,0 .1μg mL) ,检出限在0 .0 0 1～0 .0 2 7mg kg (干重)之间。

A quantitative method has been established for determination of buprofezin, methamidophos, acephate, trichlorphon, dimethoate, methlyparathion, isocarbophos, triazophos and phosalone in Chinese tea. The components of pesticide residues were extracted with mixture of acetic ether and n-hexane (1∶1, v/v) at 45℃ for 30 min. The extract was purified on a solid phase extraction column (5mm×75mm, packed with 40mg active carbon) with mixture of acetic ether and n-hexane (6∶1, v/v) as eluant. The eluant was concentrated to near dry and re-dissolved in acetone. Purified residues were separated on HP-5 capillary column (15m× 0.53mn, 1.5μm) and detected by nitrogren-phosphorus detector. Nine pesticide residues were analyzed in 11 min. The recoveries were in the range of 69.2%～101.4%. The RSDs were 4.09%～16.55% (n=6, 0.1μg/mL) and the detection limits were 0.001～0.027mg/kg (dry weight).