【摘要】 建立了浊点萃取-异辛烷反萃取-气相色谱(ECD)检测茶叶中联苯菊酯(Bifenthrin)、甲氰菊酯(Fenpropathrin)、功夫菊酯(Cyhalothrin)、氯菊酯(Permethrin)、氰戊菊酯(Fenvalerate)、溴氰菊酯(Deltamethrin)6种拟除虫菊酯农药残留的方法。对含1.2%(m/V)聚乙二醇6000(PEG6000)表面活性剂和40%(m/V)(NH4)2SO4的6种拟除虫菊酯溶液进行加热萃取,所获得的富集相用异辛烷超声反萃取,并经离心对上层异辛烷溶液进行进一步净化处理,即可获得富集倍数达75倍的6种农药。本方法的检出限(LOD)为:联苯菊酯、甲氰菊酯和功夫菊酯0.4μg/kg;氰戊菊酯2.1μg/kg;氯菊酯和溴氰菊酯3.0μg/kg;用本方法测定了新鲜茶叶中6种拟除虫菊酯农药,含量分别为4.17,4.15,4.09,4.01,3.93和3.51μg/kg。在上述茶叶样品中添加20μg/kg的6种农药后测定,添加回收率为72.3%～85.6%;相对标准偏差为2.2%～5.6%。更多还原

【Abstract】 A method was developed for the determination of pyrethroid pesticides:bifenthrin(BF),fenpropathrin(FP),cyhalothrin(CH),permethrin(PM),fenvalerate(FV)and deltamethrin(DI)in tea proposed using the cloud point extraction(CPE)coupled with ultrasonic-assisted back-extraction prior to gas chromatography with electron capture detection.A pyrethroid solution containing 1.2%(m/V)polyethylene glycol 6000(PEG 6000)and 40%(m/V)(NH4)2SO4 was heated for the extraction of the pyrethroid pesticides.The coacervation phase obtained was back extracted with isooctane.The upper isooctane solution was centrifugated simply for further cleanup.A preconcentration factor of 75 was obtained for these six pesticides.The limits of detection(LODs)were 0.4 μg/kg for BF,FP and CH,2.1 μg/kg for FV and 3.0 μg/kg for PM and DI respectively.Six pyrethroid pesticides,BF,FP,CH,FV,DM and DI,were determined,the amounts were 4.17,4.15,4.09,4.01,3.93 and 3.51 μg/kg.Six pyrethroid pesticides standards of 20 μg/kg were added in the tea samples mentioned above,the spiked recoveries were 72.3%-85.6% and the relative standard deviations were 2.2%-5.6%.更多还原