Abstract:

Gas chromatography was involved to reveal the dynamic changes of acetochlor residue and the final residue of acetochlor in rape plant, rape shell, rape kernel and soil samples. Soil samples were extracted with methanol and other samples were extracted with methylene chloride. The extracts were cleaned up by florisil. When samples were fortified with acetochlor at the levels between 0.005 mg/kg and 1.0 mg/kg, the recovery ranged from 85.3% to 96.5% for soil, 86.9% to 90.3% for rape plant, 83.3% to 89.7% for kernel, and 87.9% to 90.4% for shell, with the relative standard deviations of 3.9% to 5.0%, 3.9% to 9.5%, 6.6% to 14.3%, and 6.4% to 11.1% respectively. The limit of detection (LOD) of the method was 5×10^-12 g. The limit of quantification (LOQ) was 0.005 mg/kg for soil, and 0.01 mg/kg for other samples. The half-life of acetochlor in Putian of FujianProvince and Changsha of Hunan Province was 3.5 days and 5.2 days in soil, and 1.7 days and 2.3 days in plant, respectively. No acetochlor residue was detected in rape plant, rape shell, rape kernel and soil samples in the treatments of 750-1125 g (a.i.)/hm² at harvesting season (60 days after the treatment).