己唑醇在猕猴桃中的残留动态及安全性评价

为探明己唑醇在猕猴桃中的残留特性和安全性，建立了测定猕猴桃中己唑醇残留量的分析方法，并采用该方法研究了己唑醇在猕猴桃中的消解动态及最终残留量。样品前处理采用QuEChERS法，经乙腈提取，采用超高效液相色谱-串联质谱 (UPLC-MS/MS) 检测，外标法定量。运用所建立的方法对己唑醇在山东烟台、山西运城、陕西咸阳、湖北武汉、安徽宿州和重庆九龙坡6个试验点的猕猴桃中的残留消解动态和最终残留进行了研究。结果表明:己唑醇在猕猴桃中的消解速率较快，其残留量随时间延长而递减，符合一级反应动力学方程，半衰期为13.9~17.8 d。慢性膳食摄入风险评估结果显示，己唑醇在各类食物中的国家估算每日摄入量 (NEDI)为1.690 2 μg/(kg bw·d)，风险商 (RQ) 值为0.338，表明己唑醇在猕猴桃中的膳食摄入风险较低。30%己唑醇悬浮剂按有效成分75 mg/kg施药3次，于末次施药后21 d收获的猕猴桃食用风险较低，推荐30%己唑醇悬浮剂在猕猴桃上使用安全间隔期为21 d。

Residue dynamics and safety evaluation of hexaconazole in kiwifruit

In order to study the residual characteristic and safety of hexaconazole in kiwifruit, an analytical method was developed for the determination of hexaconazole residue in kiwifruit. The dissipation dynamics and final residues of hexaconazole in kiwifruit were investigated by this method. A simple and efficient pretreatment method called QuEChERS was used. Samples were extracted with acetonitrile and analyzed by ultra performance  liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). And the external standard and peak area method were employed for the quantitative analysis. Residual dissipation dynamics and final residue levels of hexaconazole in kiwifruit from six experimental sites (Yantai in Shandong Province, Yuncheng in Shanxi Province, Xianyang in Shaanxi Province, Wuhan in Hubei Province, Suzhou in Anhui Province and Jiulongpo in Chongqing) were determined. The results showed that the dissipation of hexaconazole in kiwifruit was rapid, with half-lives of 13.9-17.8 d. The residual contents of hexaconazole in kiwifruit decreased according to the first-order kinetics equation. The chronic dietary intake risk assessment results indicated that the national estimated daily intake (NEDI) of hexaconazole in all kinds of food was 1.6902 μg/(kg bw·d), and the risk quotient (RQ) was 0.338, which demonstrated that hexaconazole applied to kiwifruit had low risk. If kiwifruit was sprayed 3 times with 75 mg a.i./kg of 30% hexaconazole SC, 21 days after the last spraying, the residue of hexaconazole in kiwifruit had low risk for dietary. Therefore, the recommended safe interval of 30% hexaconazole SC in kiwifruit was recommended to be 21 days.