【摘要】 为建立大白菜和土壤中虫螨腈残留的气相色谱测定方法,采用乙腈提取、弗罗里硅土柱固相萃取净化、气相色谱-电子捕获检测器(GC-ECD)测定等方法,研究了虫螨腈在大白菜和土壤中的残留消解动态及最终残留量。结果表明:在0.01、0.1和1.0 mg/kg 3个添加水平下,虫螨腈的平均回收率为86.6%~108.0%,相对标准偏差(RSD)为0.4%~3.2%,最小检出量为1.0×10-12 g,最低检测浓度为0.01 mg/kg。采用20%虫螨腈悬浮剂按450 g/667m2的剂量施药,虫螨腈在大白菜中的半衰期为6.0 d,在土壤中的半衰期为7.03 d,药后7 d大白菜中的最终残留量≤1.572 mg/kg,低于我国的最大残留限量值2.0 mg/kg。建议在大白菜上使用20%虫螨腈悬浮剂时,施药制剂量为20~30 g/667m2(折合有效剂量60~90 g/hm2),施药2~3次,安全间隔期为7 d。更多还原

【Abstract】 A gas chromatography method was developed for determining chlorfenapyr residues in Chinese cabbage and soil, and the dissipation dynamics of chlorfenapyr were studied. The samples were extracted with acetonitrile, cleanded up by Florisil SPE and determined by gas chromatograph with electron capture detector(GC-ECD). The results showed that at fortified level of 0.01 to 1.0 mg/kg, the range of average recoveries and relative standard deviations of the method were 86.6% to 108.0%, 0.4% to 3.2% respectively. The limit of detection was estimated to be 1.0×10-12 g, and the limit of quantification was 0.01 mg/kg. Sprayed with high dosage of 90 g.a.i/hm2, the half-life of chlorfenapyr was 6.0 days in Chinese cabbage and 7.03 days in soil. Terminal residues in Chinese cabbage were less 1.572 mg/kg after 7 days, below the MRL of China(2.0 mg/kg). Recommended dosage of 60~90 g.a.i/hm2 for chlorfenapyr 20% SC was suggested to apply in Chinese cabbage with preharvest interval at 7 days and maxium application below three times.更多还原