螺虫乙酯及其代谢产物在猕猴桃中的残留消解动态

研究建立了螺虫乙酯及其4种主要代谢物在猕猴桃及土壤中的残留分析方法。样品用乙腈提取后,经PSA净化,高效液相色谱质谱联用仪检测,外标法定量。结果表明:在0.01～2.00mg/kg的添加水平下,螺虫乙酯及代谢产物在猕猴桃和土壤中的回收率为73.97%～110.52%,相对标准偏差分别为1.96%～7.91%。采用所建方法,测定螺虫乙酯及代谢产物在猕猴桃和土壤中的残留及消解动态。螺虫乙酯被施用到猕猴桃和土壤中后均迅速降解为B-enol、B-keto。在猕猴桃中螺虫乙酯、B-enol呈逐渐降低的趋势,而B-keto和B-mono呈逐渐升高的趋势;在土壤中螺虫乙酯、B-enol、B-keto均呈逐渐降低趋势,B-mono和B-glu在样品中均没有检出。螺虫乙酯和B-enol在土壤中的降解速度(1.42 d、1.99 d)快于在猕猴桃上的降解速度(4.08 d和6.39 d)。以3000倍液稀释液喷施2次,28 d后,猕猴桃中螺虫乙酯母体的残留量为0.06 mg/kg,高于我国制定的0.02 mg/kg的最大残留限量值,在猕猴桃上的安全使用剂量还需要进一步研究。

Residue and Dissipation of Spirotetramat and Its Metabolites in Kiwifruits and Soil

This paper developed a rapid method for analyzing the spirotetramat and its four major metabolites residues in kiwifruits and soil. Samples were extracted with acetonitrile, cleaned up by Solid Phase Extraction PSA and detected by using high performance liquid chromatography-tandem mass spectrometry. Average recoveries of spirotetramat and its four major metabolites fortified at 0.01~2.00 mg/kg in kiwifruits and soil ranged from 73.97%~110.52% with the relative standard deviations (RSD) of 1.96%~7.91%, respectively. Using the above method, residue dissipation of spirotetramat and its metabolites in kiwifruits and soil were detected. After spirotetramat is applied to the soil and kiwi, it was rapidly degraded as B-enol, B-keto. In the kiwifruit, the spirotetramat and B-enol gradually decreased, while the B-keto and B-mono showed a gradual increase. In the soil, spirotetramat, B-enol and B-keto showed a decreasing trend, and B-mono and B-glu were not detected in the samples. The degradation rates of spirotetramat and B-enol in soil (1.42 d and 1.99 d, respectively) were faster than those on kiwifruit (4.08 d and 6.39 d, respectively). Sprayed twice with 3000 times liquid dilution, after 28 days, the residual amount of spirotetramat in kiwifruit was 0.06 mg/kg, which was higher than the maximum residue limit of 0.02 mg/kg formulated in China, the safe use of kiwifruit requires further study.