大米中吡虫啉和噻嗪酮残留分析方法

研究了分别用高效液相色谱和气相色谱测定大米中吡虫啉和噻嗪酮残留量的检测方法。采用乙腈作为大米中吡虫啉和噻嗪酮的共同提取溶剂,部分提取溶液通过氟罗里硅土固相萃取小柱净化,以Wa-ters-C18色谱柱为分离柱,乙腈–水(20∶80,体积比)为流动相,用高效液相色谱二极管阵列检测器检测(检测波长270 nm)吡虫啉的残留量;部分提取溶液通过氨基固相萃取小柱净化,以弹性石英玻璃毛细管柱为分离柱,用气相色谱电子俘获检测器检测噻嗪酮的残留量。结果表明,样品在不同水平的加标回收试验中,吡虫啉的平均回收率为89.2%～96.4%,相对标准偏差为2.5%～8.5%;噻嗪酮的平均回收率为86.6%～105.8%,相对标准偏差为2.6%～5.5%;两种农药的最低检出浓度均为0.02 mg/kg。该测定方法简单、准确、精密度高、重现性好。

Analysis Method of Imidacloprid and Buprofezin Residue in Rice

The analytical methods to determine the quantity of imidacloprid and buprofezin residue in rice adopt high performance liquid chromatography and gas chromatography.Acetonitrile is used as the common solvent to extract imidacloprid and buprofezin from the rice.Parts of the extraction solution are purified by Florisil SPE mini column and the imidacloprid residue quantity is analyzed with high performance liquid chromatography photo-diode array(the detective wave length is 270 nm.) while Waters-C18 chromatographic column serving as the separation column and acetonitrile-water(20∶80,V/V) as the liquid phase;Part of the extraction solution is purified by NH2 solid phase extraction column,and with the elastic silica glass capillary column working as the separation column,the buprofezin residue quantity is detected with a gas chromatography electron capture detector..As the result data indicates,in the sample under the different levels of adding standard recovery tests,the average recovery rate of imidacloprid ranges from 89.2% to 96.4% and the relative standard deviations ranges from 2.5% to 8.5%;the average recovery rate of buprofezin ranges from 86.6% to 105.8% and the relative standard deviation ranges from 2.6% to 5.5%.The lowest detectable concentration of the two pesticides are both 0.02 mg/kg.The methods are simple,accurate,high in precision and satisfying in repeatability.