茚虫威在金银花中的残留动态研究及安全性评价

为了探明茚虫威在金银花中的残留特性和安全性,对茚虫威在金银花中的消解动态及最终残留进行了研究。样品经乙腈提取,超高效液相色谱-串联质谱(UPLC-MS/MS)检测,外标法定量。运用所建立的方法对茚虫威在山东泰安、河北邢台、浙江杭州、湖南邵阳、广东湛江和重庆九龙坡6个试验点的金银花中的残留消解动态和最终残留进行了研究。试验结果表明:茚虫威残留量在金银花中随时间延长而递减,符合一级反应动力学方程,消解速度较快,半衰期为1.5～2.2 d,属易消解型农药。参照中国制定的茶叶中茚虫威的最大残留限量(MRL)5 mg/kg,15%茚虫威悬浮剂按推荐使用剂量90 g/hm~2,施药1次,施药后7 d,所采收的金银花中的茚虫威残留量低于5 mg/kg。研究结果可为茚虫威在金银花上的合理使用及其最大残留限量制定提供参考。

Residue dynamics and safety evaluation of indoxacarb in honeysuckle

In order to investigate the residual characteristic and safety of indoxacarb in honeysuckle, to set up standard procedure for the safe use of indoxacarb in honeysuckle, an analytical method was developed for the determination of indoxacarb residue in honeysuckle. Samples were extracted with acetonitrile, and then analyzed by UPLC-MS/MS. Residual dissipation dynamics and final residue levels of indoxacarb in honeysuckle from six experimental sites (Taian in Shandong province, Xingtai in Hebei province, Hangzhou in Zhejiang province, Shaoyang in Hunan province, Zhanjiang in Guangdong province and Jiulongpo in Chongqing municipality) were determined. The results showed that the dissipation of indoxacarb in honeysuckle were rapid, with half-lives of 1.5-2.2 d. The residual contents of indoxacarb in honeysuckle decreased according to the first-order kinetics equation, indicating that indoxacarb is an easily degradable pesticide. When 15% indoxacarb SC was sprayed once at the recommended dose 90 g/hm2, indoxacarb residues in harvested honeysuckle after 7 days were below 5 mg/kg, indicating it was relatively safe according to the maximum residue limits(MRL) of indoxacarb in tea in China (5 mg/kg).The results provide a reference for the rational use and the MRL standard development of indoxacarb in honeysuckle.