乙氧氟草醚在大蒜和土壤中的残留动态

采用田间试验方法研究了乙氧氟草醚在大蒜和土壤中的残留和降解情况,以评价大蒜生产中乙氧氟草醚残留对环境的污染程度以及所得产品的食用安全性。样品经丙酮/乙酸乙酯提取,微波加热处理,弗罗里硅土柱净化,气相色谱-质谱联用仪检测。结果显示,乙氧氟草醚在0.01~1.0 mg/L范围内线性关系良好,相关系数为0.9980,在大蒜及其植株和土壤中的添加回收率为85.2%~104.1%,相对标准偏差为1.8%~9.6%。在大蒜植株中残留量太低,以致消解现象不明显;土壤中消解明显,半衰期为15.4~18.6天,药后42天消解90%以上。使用30%乙氧氟草醚·扑草净可湿性粉剂按照900 g a.i./hm2和1 350 g a.i./hm2用药量分别土壤喷雾,不同收获期的蒜薹及大蒜样品中乙氧氟草醚的残留量均小于检出限0.01 mg/kg,低于日本和以色列规定的最高残留限量0.05 mg/kg。综上所述,使用30%乙氧氟草醚·扑草净可湿性粉剂防治大蒜田间杂草,按450~900 g a.i./hm2于大蒜播种后发芽前土壤喷雾处理一次,所收获产品食用安全。

Residue Dynamics of Oxyfluorfen in Garlic and Soil

To evaluate the environmental pollution and the food safety of applying oxyfluorfen in garlic production , the residue and digestion dynamics of oxyfluorfen in garlic and soil were studied by field experi-ment.The samples were extracted by acetone/ethyl acetate , heated by microwave , purified by Florsil column , and then analyzed by gas chromatograph -mass spectrometer （ GC-MS） .The results showed that the linear relationship of oxyfluorfen in the range of 0 .01 ~1 .0 mg/L was good with the correlation coefficient of 0 .9980 .The fortified recovery in garlic , plants and soil ranged from 85 .2% to 104 .1% with the relative standard deviation （RSD） of 1.8%~9.6%.The residual quantity in garlic plants was too low to observe the digestion dynamic .Whereas , the digestion dynamic in soil was clear .The half-life period was 15 .4~18 .6 days, and the residue was digested more than 90%on the 42th day after application.Spraying 30%oxyfluor-fen and prometryn WP at the dosage of 900 g a.i./hm2 and 1 350 g a.i./hm2 respectively, the residual quan-tities of oxyfluorfen in garlic and garlic sprout were both less than the limit of detection （ LOD） of 0.01 mg/kg, and the maximum residue level （MRL） in Japan and Iarael of 0.05 mg/kg.In conclusion, to control weeds in garlic field, spraying 30%oxyfluorfen and prometryn WP at the dosage of 450~900 g a.i./hm2 be-fore seed germination , the products were safe .