氯虫苯甲酰胺在水稻及稻田环境中的残留动态

Residue and degradation of chlorantraniliprole in rice and the environment

采用田间试验方法,研究了氯虫苯甲酰胺在稻田水、土壤和水稻植株中的消解动态,测定了氯虫苯甲酰胺在水稻和土壤中的最终残留量。稻田水和土壤样品采用丙酮提取,水稻样品用乙腈溶液浸泡提取,经玻璃层析柱净化,HPLC紫外分析测定。结果表明,稻田水、土壤、水稻植株、谷壳、糙米中氯虫苯甲酰胺添加浓度为0.005~1.0mg/kg时,平均回收率为85.06%~95.83%,变异系数在2.08%~5.77%之间。方法的最低检测浓度为：稻田水0.005mg/kg,土壤0.01mg/kg,水稻植株0.02mg/kg,谷壳0.02mg/kg,糙米0.01mg/kg。氯虫苯甲酰胺在稻田水、土壤和水稻植株中的消解动态均符合一级动力学方程,半衰期分别为3.1~5.0d、6.6~9.0d、8.0~9.9d。以33.86g/hm2和50.80g/hm2间隔14d施用氯虫苯甲酰胺2次和3次,末次施药21d后氯虫苯甲酰胺的最高残留量为：土壤0.217mg/kg,水稻植株0.879mg/kg,谷壳0.389mg/kg,糙米0.018mg/kg。氯虫苯甲酰胺在糙米中的残留量低于我国和食品法典委员会（CAC）及欧盟的最大残留限量（MRL）标准。

The residue dynamics of chlorantraniliprole in paddy water, soil and rice plant was studied, and its final residue in paddy and soil was determined by using field test. The residues of paddy water and soil samples were ex- tracted with acetone, and rice samples were cleaned up by glass chromatographic column after the extraction with acetonitrile, and determined by HPLC-UV. The results showed that, while the spiked concentration of chloran- traniliprole in paddy water, soil, rice plant, rice shell and brown rice ranged from 0.005 mg/kg to 1.0 mg/kg, the av- erage recovery was 85.06%-95.83% with the variation coefficient of 2.08%-5.77%. The minimum detectable mass fraction in paddy water, soil, rice plant, rice shell and brown rice samples were 0. 005, 0.01, 0.02, 0. 02, 0.01 mg/kg, respectively. Degradation of chlorantraniliprole in paddy water, soil and rice plant conformed to chemical kinetic equation. The half-life was 3.1-5.0 days in paddy water, 6.6-9.0 days in soil and 8.0-9.9 days in plant. Chlorantraniliprole was sprayed twice or three times at a 14 days interval with the application dose of 33.86 g/hm2 and 50.80 g/hm2 , the final maximum residue of chlorantraniliprole after 21 days were 0. 217 mg/kg in soil, 0. 879 mg/kg in rice plant, 0. 389 mg/kg in rice shell and 0. 018 mg/kg in brown rice, respectively. The residue in brown rice could be lower than the MRL （maximum residue limit）in China, CAC and EU.