联苯菊酯在甘蔗和土壤中的残留分析及消解动态

Residue Analysis and Degradation Dynamics of Bifenthrin in Sugarcane and Soil

[方法]采用GC-ECD法测定联苯菊酯在甘蔗植株、茎秆及土壤中的消解动态和最终残留。样品用乙腈提取,N-丙基乙二胺（PSA）净化。[结果]联苯菊酯最小检出量（LOD）为7.93×10-13 g,在植株、茎秆的最低检测质量分数（LOQ）为0.005 mg/kg,在土壤中的为0.004 6 mg/kg。[结论]联苯菊酯在植株和土壤中的消解行为均符合一级降解动力学方程,半衰期分别为34.7～36.5、6.4～19.3 d。建议联苯菊酯在甘蔗上的使用剂量不超过900 g a.i./hm2。

[Methods] Degradation dynamics and final residue of acetochlor in sugarcane plant, stalk and soil samples were studied by Gas chromatography equipped with an Electron-capture detector （GC-ECD）. The samples were extracted with acetonitril, and the extracts was cleaned up by PSA. [Results] The limit of detection （LOD） of the method was 7.93×10-13 g, while the limit of quantification （LOQ） was 0.005 mg/kg for sugarcane plant, stalk and 0.004 6 mg/kg for soil. [Conclusions] The degradation dynamics of bifenthrin in plant and soil accorded with the one-level kinetics equation, and the half-lives of bifenthrin in plant and soil were 34.7-36.5, 6.4-19.3 d, respectively. Therefore, it is suggested that the recommended dosage ofbifenthrin used in sugarcane was lower than 900 g a.i./laa.