溴虫腈在黄瓜和苋菜中的残留动态研究

Study on Residue Dynamics of Chlorfenapyr in Cucumber and Amaranth

通过田间试验和气相色谱分析，研究了溴虫腈在黄瓜Cucumissativus和苋菜Amaranthus rnangostanus中的残留消解动态和最终残留量．样品经丙酮提取抽滤后，二氯甲烷萃取分离，过氧化铝和活性炭柱净化，用带ECD检测器的气相色谱进行测定．结果表明，溴虫腈在黄瓜和苋菜中的消解较快．W为10％除尽（溴虫腈）悬浮剂使用量为0．075mL·m^-2时，在黄瓜和苋菜中的降解动态方程分别为Ct=6．3680e-0.1512t和Ct=5．3325e-0.5680t，半衰期为3．4和1．2d；使用量为0．112mL·m^-2时，在黄瓜和苋菜中的降解动态方程分别为Ct=22．1660e-0.2046t和Ct=7．9309e-0.5584t，半衰期为4．6和1．2d．在正常使用条件下，无论是推荐剂量还是1．5倍推荐剂量，施药2～3次，药后7和14d，溴虫腈在黄瓜和苋菜中的最终残留都低于美国国家环保署规定的蔬菜最大允许残留量（1mg·kg^-1）．

In order to evaluate the safety of chlorfenapyr in cucumber and amaranth, a field experiment was conducted for revealing the residual dynamics and final residues of chlorfenapyr in cucumber and amaranth. Two pesticides were extracted with acetone and dichloromethane, purified by precipitation, liquid-liquid partition and cleaned up by passing through aluminum oxide and an activated carbon column, followed determined by GC-ECD. When adding chlorfenapyr at the concentration of 0. 075 mL· m^-2, the residue degradation equations of 10% （w） suspension concentrates in cucumber and amaranth were Ct= 6. 368 0e -0.151 2t and Ct= 5.332 5e -0.568 0t respectively, and the half lives were 3.4 and 1.2 d, respectively. The residue degradation equations of 10% （w） suspension concentrates in cucumber and amaranth were Ct = 22. 166 0e -0.2046t and Ct =7.930 9e-0.55t4t,and the half lives were 4.6 and 1.2 d, respec tively, at the concentration of 0. 112 mL· m^-2 When chlorfenapyr at the recommended dosage or at the 1.5 times recommended dosage was applied at 2 or 3 times on cucumber and amaranth, detectable residues in cucumber and amaranth at 7 or 14 d after the last application was much lower than the USA EPA＇ s maximum residue limit of 1 mg ·kg^-1 in vegetable.