丙酯草醚在油菜和土壤中的残留动态研究

Pyribambenz-propyl Residue Dynamics in Rape and Soil

利用自行探索的液相色谱紫外检测方法研究了除草剂丙酯草醚在河北、湖北两地油菜和油菜田土壤中的残留规律。结果表明,该方法丙酯草醚最低检出浓度为0.006mg·kg-1,添加浓度在0.01～1.0mg·kg-1范围内,回收率为81.0%～95.7%,变异系数为1.56%～5.19%。丙酯草醚在河北、湖北两地油菜中的消解动态方程分别为C=2.56e-0.0903T和C=2.56e-0.115T,在土壤中的消解动态方程分别为C=0.232e-0.0568T和C=2.01e-0.0639T,在两地油菜中的半衰期分别为7.67d和6.05d,在两地土壤中的半衰期分别为12.2d和10.9d。10%丙酯草醚悬浮剂用于油菜田除草,施药剂量有效成分为45～60g·hm-2,施药1次,收获期油菜籽及油菜植株中丙酯草醚残留量低于0.01mg·kg-1,土壤中丙酯草醚残留量低于0.02mg·kg-1。

A method was developed to probe the residue dynamics of pyribambenz-propyl and its final residue state in rape and soil in Hebei and Hubei provinces of China. The samples of rape plant and soil were extracted with acetone ,while the rapeseed was extracted with acetoni- trile. The extracts were separated with methylene dichloride by liquid-liquid extraction and cleaned up with silica gel cartridges. A HPLC- UV detection was used to determine the residue of pyribambenz-propyl. The separation was carried out on a Hypersil XDB-C18 column with a mobile phase of methanol/water （90：10）at a flow rate of 0.8 mL· min^-1. The detection wavelength was 305 nm. The limit of determination was 0.006 mg· kg^-1. When the added concentration of pyribambenz-propyl ranged from 0.01 mg· kg^-1 to 1.0 mg· kg^-l, the recoveries changed from 81.0% to 95.7%, and the coefficients of variation varied from 1.56% to 5.19%. The results indicated that, the kinetic equations of pyribambenz-propyl degradation in rape plant were C=2.56^-0.0903T and C=2.56^-0.115T in Hebei and Hubei and the half lives were 7.67 d and 6.05 d, the kinetic equations of pyribambenz-propyl degradation in soil were C=0.232^-0.0568T and C=2.01e^-0.0639T in Hebei and Hubei and the half lives were 12.2 d and 10.9 d, respectively. According to the research, when pyribambenz-propyl 10% aqueous suspension concentrate was applied one time to control the weeds in rape fields with the dosages of active ingredient of 45-60 g·hm^-2, the final residues of pyribambenz-propyl in rapeseed and rape plant were less than 0.01 mg· kg^-1, and the final residues in soil were less than 0.02 mg· kg^-l.