嘧菌酯在枇杷中残留及消解动态

Residue and Degradation Dynamics of Azoxystrobin in Loquat

为评价嘧菌酯在枇杷中的消解动态和最终残留,2016年开展了250g/L嘧菌酯悬浮剂在枇杷上的残留田间试验,以期为嘧菌酯在枇杷上的合理使用和制定最终残留限量提供参考。建立了液相色谱串联质谱法(LC-MS/MS)测定枇杷中嘧菌酯的残留量的分析方法。当嘧菌酯在枇杷中的添加浓度为0.05、1.0、2.Omg/kg时,平均回收率为112.4%~117.1%,相对标准偏差(RSD)为5.6%~6.4%,符合农药残留试验要求。消解动态试验结果显示,嘧菌酯在枇杷中的消解动态规律符合一级动力学方程,半衰期为7.9~12.2d,属易降解农药。最终残留试验表明250g/L嘧菌酯悬浮剂按有效成分416.7和625.05 mg/kg,施药3次和4次,,末次施药后7、14、21d,枇杷中嘧菌酯最终残留量分别为0.147~2.051mg/kg、0.145~1.379mg/kg、0.015~1.004mg/kg。建议在枇杷上使用250g/L嘧菌酯悬浮剂时,有效成分用药量321.5~416.7mg/kg,最多施药3次,安全间隔期21d。

The residue and degradation dynamics of azoxystrobin in loquat were investigated to pro- vide the reference for the safe use of pesticides and establish the maximum pesticide residue lira- its. The field residue trials of azoxystrobin 250g/L SC in loquat were carried out in 2016. A LC - MS - MS method was established for the determination of azoxystrobin residues in loquat. Under the fortified level of 0. 05mg/kg, 1.0mg/kg, 2.0mg/kg, the average recovery ranged from 112.4% to 117. 1% with the relative standard deviations of 5.6% - 6.4%, which met the requirements of re- sidual analysis. The results showed the degradation of azoxystrobin in loquat complied with the first order kinetics equation with the half- life of 7.9 ~ 12.2 days, indicating that azoxystrobin in loquat was degraded very fast and could be classified as easily - degraded pesticide. In the final residue test, the final azoxystrobin residues in loquat were found to be 0. 147 - 2. 051 mg/kg, 0. 145 1. 379mg/kg, O. 015- 1. 004mg/kg, respectively, at 7, 14 and 21 days after the last application when sprayed 3 - 4 times at the dosage of 416. 7 and 625.05 mg/kg. Azoxystrobin 250g/L SC was recommended to be used in loquat at the dosage of 321.5 ~ 416. 7mg/kg, with the maximum appli- cation frequency of 3 times and the safety interval of 21days.