烟草中菊酯类农药残留量及其捕集转移率的测定

Determination of Residues of Pyrethroids in Tobacco and Their Collectoin of Shifting Efficiency by Capillary Gas Chromatography

建立了一种同时测定烟草中5种拟除虫菊酯农药残留量及其捕集转移率的毛细管气相色谱法 ;样品经丙酮提取 ,石油醚萃取 ,硅酸镁载体净化 ,GC -ECD(63Ni)检测 ,外标法定量 ;实验表明 ,加标0.01×10-6～1.0×10-6 含量水平的功夫菊酯和溴氰菊酯 ,回收率为90%～96 % ,加标0.2×10-6～20×10-6 含量水平的甲氰菊酯、氯氰菊酯和氰戊菊酯 ,回收率为92 %～102 % ;同一样品中10次测定这5种菊酯类农药残留量的相对标准偏差为4.4 %～13%。

A method is presented for the simultaneous determination of the residues of five pyrethroids: fenpropathrin, cyhalothrin, cypermethrin, fenvalerate and deltamethrin, in tobacco, and their collection of shifting efficiency by capillary gas chromatography. The pyrethroids in sample were extracted by acetone, then reextracted by petroleum ether. The petroleum ether extract was purified by solid phase extraction through a florisil column and eluted with a mixture of petroleum ether and ethyl acetate. Chromatographic analysis was performed with Shimadzu GC _ 14B equipped HP _ 5(30 m×0.32 mm id×0.25 μm) and 63Ni electron capture detector. The pyrethroids were quantified by external standard method. The recoveries were in the range of 90%～102% and relative standard deviations(n=10) were from 4.4% to 13%.