乙羧氟草醚在棉花及土壤中的残留动态研究

Residue Dynamics of Fluoroglycofen-ethyl in Cotton and Soil

采用气相色谱法测定了乙羧氟草醚在浙江、山东两地棉花和土壤中的残留规律。结果表明,乙羧氟草醚最低检出浓度为0.01 mg/kg,添加浓度在0.01～0.50 mg/kg范围内,回收率为88.8%～102.2%,变异系数为2.44%～5.77%。乙羧氟草醚在浙江、山东两地棉叶中的消解动态方程分别为C=0.628 8e-0.3933T和C=0.410 2e-0.3852T,在土壤中的消解动态方程分别为C=0.119 2e-0.5343T和C=0.010 7e-0.2715T;在两地棉叶中的半衰期分别为1.76 d和1.80 d,在两地土壤中的半衰期分别为1.30 d和2.55 d。10%乙羧氟草醚乳油用于棉花田除草,施药剂量(有效成分)为60～90 g/hm2,施药1次,收获期棉子及土壤中乙羧氟草醚残留量均低于0.01 mg/kg。拟推荐我国棉花(棉子)中乙羧氟草醚的最高残留限量(MRL)为0.01 mg/kg。

A method was developed to study the residue dynamics of fluoroglycofen-ethyl and its final residue state in cotton and soil in Zhejiang and Shangdong provinces of China by gas chromatography.The limit of determination was 0.01 mg/kg.When the spiked concentration of fluoroglycofen-ethyl ranged from 0.01 mg/kg to 0.5 mg/kg,the recoveries changed from 88.8% to 102.2%,and the coefficients of variation varied from 2.44% to 5.77%.The results indicated that the kinetic equations of fluoroglycofen-ethyl degradation in cotton leaves were C=0.628 8e-0.393 3T and C=0.410 2e-0.385 2T in Zhejiang and Shangdong provinces and the half lives were 1.76 d and 1.80 d,the kinetic equations of fluoroglycofen-ethyl degradation in soil were C=0.119 2e-0.534 3T and C=0.010 7e-0.271 5T in Zhejiang and Shangdong provinces and the half lives were 1.30 d and 2.55 d.According to the research,when 10% fluoroglycofen-ethyl EC was applied one time to control the weeds in cotton fields with the dosages of active ingredient of 60～90 g/hm2,the final residues of fluoroglycofen-ethyl in cotton seeds and soil were less than 0.01 mg/kg.The recommended MRL for fluoroglycofen-ethyl in cotton seed was 0.01 mg/kg in China.