乙草胺在水稻环境中的残留及消解动态

采用气相色谱-电子捕获检测器(GC-ECD)测定了乙草胺在水稻植株、稻田水样及土壤中的消解动态和最终残留。水稻和水样样品用二氯甲烷提取,土壤用甲醇提取,经液液分配净化, GC-ECD检测,外标法定量。结果表明:当乙草胺在植株、水样和土壤中的添加量在0.05~1.0 mg/kg 水平时,添加回收率分别为87.2% ~96.8%、94.0% ~99.3%和83.6% ~93.7%,相对标准偏差分别为3.80% ~7.66%、3.46% ~7.54%和2.70% ~6.41%。乙草胺的最小检出量(LOD)为1.29×10-11 g,在稻米中的最低检测浓度(LOQ)为1.3×10-3 mg/kg。乙草胺在植株、水样和土壤中的半衰期分别为1.21 ~2.07 ｄ、1.30 ~2.56 ｄ和1.22 ~2.41 ｄ。施药浓度为推荐剂量1次,在收获的稻米中乙草胺的残留量均低于最低检测浓度。

Residue and Field Decline Study of Acetochlor in Rice Field

Gas chromatography equipped with an Electron-capture detector (GC-ECD) was conducted to reveal the residue dynamics and final residues of acetochlor in rice,water and soil samples.Soil samples were extracted with methanol and other samples were extracted with methylene chloride.The extracts were cleaned up by liquid to liquid separation.The recovery ranged from 87.2% to 96.8% for paddy,94.0% to 99.3% for water,83.6% to 93.7% for soil with the relative standard deviations of 3.80% to 7.66%,3.46% to 7.54% and 2.70% to 6.41% respectively.The limit of detection(LOD) of the method was 1.29×10^-11 g.The limit of quantification(LOQ) was 1.3×10^-3 mg/kg for rice.The half-life of acetochlor was 1.21 to 2.07 days in paddy,1.30 to 2.56 days in water and 1.22 to 2.41 days in soil,respectively.When applied once at the dosage of 90 g/hm²,the final residues of acetochlor in rice were lower than LOQ.