吡唑醚菌酯在苹果和土壤中的消解及安全性评价

Dissipation and Safety Evaluation of Pyraclostrobin in Apple and Soil

[目的]研究吡唑醚菌酯在苹果及土壤中的消解动态和残留变化趋势，评价吡唑醚菌酯在苹果上使用的安全性。[方法]吡唑醚菌酯经乙腈超声辅助提取，N-丙基乙二胺（PSA）净化，高效液相色谱（HPLC）检测。[结果]在加标量0．05。5．0mg／kg的范围内，添加回收率为90．8％-94．2％，相对标准偏差（RsD）为0．9％-2．1％，定量限（LOQ）为0．05mg／kg，在0．1～7．5mg／ks的范围内线性良好。在北京和安徽2地，苹果中吡唑醚菌酯的半衰期为16．5、15．4d，土壤中半衰期为19．3、21．0d。按推荐剂量的高剂量、次数进行施药，3个采收间隔期（21、28、35蝉果上的残留量在0．08—0．16mg／kg范围内。[结论]参照我国规定吡唑醚菌酯在苹果上的最大残留限量（MRL）标准0．5mg／kg，按推荐方法使用，间隔35d后的苹果是相对安全的。

[Aims] Based on the method for the determination of pyraclostrobin in apple and soil, the dissipation dynamics and residues in apple and soil were investigated, and the safety of the application of this pesticide on apple was evaluated. [Methods] The samples were extracted with acetonitrile by ultrasound-assisted method, purified by primary secondary amine （PSA）, and determined by high performance liquid chromatography equipped with ultraviolet detector （HPLC- UV）. [Results] At fortified levels of 0.05-5.0 mg/kg, the average recoveries ranged from 90.8 to 94.2%, with the relative standard deviations （RSD） of 0.9-2.1%. The limit of quantification （LOQ） was 0.05 mg/kg. The linearity was acceptable in the range of 0.1-7.5 mg/kg. The results showed that the half-lives （t1/2） were 15.4 and 16.5 d in apple, while 19.3 and 21.0 d in soil from Beijing and Anhui, respectively. The final residues of pyraclostrobin in apple were in the range of 0.08-0.16 mg/kg on 21, 28 and 35 d after the last application with the high level of recommend dose and times. [Conclusions] The pyraclostrobin residue in apple harvested at 35 d after the final application was below the maximum residue limit set by China （MRL, 0.5 mg/kg）, therefore, the apple was relatively safe to human.