气相色谱法同时测定玉米中12种三嗪类除草剂的残留量

Simultaneous Determination of Triazine Herbicide Residues in Maize by Gas Chromatography

建立了气相色谱-氮磷检测器同时检测玉米中12种三嗪类除草剂（西玛通、西玛津、阿特拉津、扑灭津、特丁通、特丁津、环丙津、西草净、扑草净、特丁净、甲氧雨净、环嗪酮）残留量的方法。玉米样品用乙腈萃取，强阳离子交换（SCX）固相萃取柱净化后，用DB-5弹性石英毛细管柱（30m×0．25mmi．d．×0．25ixm）分离样品，氮磷检测器测定。12种三嗪类除草剂在0．01～2．0mg／L范围内线性关系关系良好。相关系数均大于0．998；最低检测限为0．01mg／kg；添加回收率为84．0％-106．8％；相对标准偏差为0．9％～4．7％。

A gas chromatographic method was developed for the determination of simeton, simazine, atrazine, propazine, terbumeton, terbuthylazine, cyprazine, simetryn, prometryn, terbutryn, methoprotryne, hexazinone residues in maize. The triazine herbicide residues were extracted with acetonitrile by blender and then cleaned up on a strong cation-exchange （SCX） solid-phase extraction cartridge. The SCX cartridge was conditioned with acetone, methylene chloride, washed with methylene chloride, acetone and eluted with methanol-water （9： 1, v/v） solution saturated potassium chloride. As a result, most interfering impurities were removed in the SPE cleanup procedure. The gas chromatographic analysis was performed on a capillary column （DB-5, 30 m × 0.25 mm i. d. × 0. 25μm） and determined by nitrogen phosphorus detector （NPD）. Twelve triazine herbicides were effectively separated on this column. Diazinon was used as the internal standard for the determination. Linear correlation coefficients of the 12 herbicides were higher than 0.998 in the range of 0.01 to 2.0 mg/L. The limits of quantitation of the method were 0.01 mg/kg for these compounds. Average recoveries of these herbicides from spiked samples ranged from 84.0 % to 106.8% at fortification levels of 0.01 -0.5 mg/kg and the relative standard deviations （RSDs） were between 0.9% and 4.7%. The method is suitable for the simultaneous determination of a wide range of triazine herbicides in maize in commodities inspection.