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采用气相色谱-微池电子俘获检测器(GCμ-ECD)测定了900g/L异丙草胺乳油在土壤、玉米植株和玉米籽粒中的消解动态和最终残留。土壤、玉米植株和籽粒样品用石油醚-丙酮(1∶1,体积比)提取,经液液萃取,弗罗里硅土柱净化,GCμ-ECD检测,外标法定量。结果表明:异丙草胺在各供试样品中的添加水平为0.011~1.1mg/kg时,回收率在78.8%~96.4%之间,相对标准偏差(RSD)为0.54%~10.5%;在土壤、玉米植株和籽粒中的定量限(LOQ)均为0.011mg/kg。异丙草胺在土壤和玉米植株中的半衰期,2009年分别为4.7~5.3d和4.1~4.5d,2010年分别为5.4~5.5d和4.9~5.4d。按推荐高剂量(有效成分)2 400g/hm2及其1.5倍剂量(3 600g/hm2)施药,于玉米苗后茎叶初期施药1次,在玉米乳熟期和成熟期时,玉米籽粒中异丙草胺的最终残留量均低于定量限。玉米收获时(距施药45d),土壤和玉米中的异丙草胺残留量均低于参考的MRL值(0.1mg/kg),说明按规定在玉米田使用900g/L的异丙草胺乳油是安全的。
The digestion kinetics and final residues of 900 g / L isopropylamine emulsifiable concentrate in soils, corn plants and maize kernels were determined by gas chromatography-microchannel electron capture detector (GCμ-ECD). Soil, corn plants and grain samples were extracted with petroleum ether-acetone (1: 1, volume ratio), and were purified by liquid-liquid extraction, Florisil column purification, GCμ-ECD assay and external standard method. The results showed that the recoveries ranged from 78.8% to 96.4% with relative standard deviations (RSDs) of 0.54% -10.5% when the concentration of isopropachloride was 0.011-1.1 mg / kg in each sample. The limit of quantification (LOQ) in soil, corn plants and grains was 0.011 mg / kg. The half-lives of propisochlor in soils and maize plants were 4.7-5.3 d and 4.1-4.5 d in 2009 and 5.4-5.5 d and 4.9-5.4 d in 2010, respectively. According to the recommended high dose (active ingredient) 2,400g / hm2 and its 1.5 times the dose (3,600g / hm2) application, the maize seedling stems and leaves early application 1 time, corn milky maturity and maturity, corn kernels The final residues of meprotic were below the limit of quantitation. Maize harvest (from the application of 45d), soil and maize areopropanilide residues were lower than the reference MRL value (0.1mg / kg), indicating the use of corn in the field of 900g / L isopropilium EC is safe.