【作者】 查玉兵；

【导师】 岳永德；

【作者基本信息】 安徽农业大学 ， 农药学， 2006， 硕士

【摘要】 本文通过对检测条件、提取体系的筛选,建立了一种以高效液相色谱（HPLC）为基础的除虫脲在小麦中的残留分析标准方法,并对方法的灵敏度、准确度和精密度进行了分析,探讨了标准溶液、样品提取液以及样品中除虫脲的稳定性,研究了该方法在大豆、小麦和花生中的基质适用性。主要研究结果如下:1.高效液相色谱条件:C18 Thermo Hypersil—ODS反相色谱柱,4.6 mm （i.d.）×250mm,流动相:乙腈/水（60/40,V/V）,流速:1.0 mL/min,检测波长:λ= 254 nm,柱温: 30℃,进样量:20μL,保留时间约7.9min。在该条件下,可以对除虫脲准确定性和定量。2.提取体系的筛选提取方法:机械振荡法和超声波振荡提取法对小麦中除虫脲的平均回收率分别为89.37%和80.60%,优化后的提取方法为机械振荡法。提取溶剂:丙酮、乙酸乙酯、二氯甲烷和乙腈对小麦中除虫脲的平均回收率分别为91.27%、72.12%、89.37%和90.55%,优化后的提取溶剂为乙腈。提取时间:机械振荡提取40、60和80min对小麦中除虫脲的平均回收率分别为68.15%、81.97%和82.45%,优化后的提取时间为60min。提取次数:一次、两次和三次提取时小麦中除虫脲的平均回收率分别为81.97%、89.37%和91.26%,优化后的提取次数为两次。3.添加回收实验及方法的灵敏度、准确度、精密度实验在小麦中分别添加0.04mg·kg^-1、0.2mg·kg^-1（MRL）和1.0mg·kg^-1的除虫脲标准溶液,得到的平均添加回收率分别为90.87%、89.37%和90.25%,变异系数分别为4.15、2.37%和3.37%%,均满足农药残留分析要求。小麦中除虫脲的最低检出浓度为0.04mg·kg^-1。4.基质适用性实验用优化后的方法分别在大豆、大米、安庆和六安地区小麦中添加0.2mg·kg^-1进行添加回收实验,测定其平均添加回收率分别为88.75%、90.13%、92.10%和84.15%,变异系数分别为3.96%、2.18%、2.26%和1.98%。结果证明本文优化的方法同样适用于以上基质,且均满足农药残留分析要求。5.稳定性实验在-20℃、4℃和25℃条件下贮存90天后,除虫脲在乙腈中的分解率分别为0.49%、2.19%和4.78%,表明除虫脲的标准工作液具有良好的稳定性;小麦提取液中的除虫脲在-20℃、4℃和25℃条件下贮存30天后,分解率分别为1.97%、2.10%和3.38%;小麦中的除虫脲在-20℃、4℃、25℃条件下贮存10天,稳定性良好,残存率均在99%以上,贮存60天后分解率分别为2.18%、3.03%和4.15%。6.质量控制实验本文分别对方法的准确度和精密度进行了质量控制分析,结果表明在0.2mg·kg^-1的添加水平下准确度和精密度均处于控制状态,分析结果有效。7.方法的优越性本文的方法作为单残留分析方法在整体上简单易行、操作过程耗时较短、所使用的溶剂量小、重现性好。方法具有较强的基质适用性,本方法适用于大豆和大米等基质中除虫脲残留分析。更多还原

【Abstract】 To establish a national standard method of residue analysis of diflubenzuron in wheat by selection of determination condition and extracting system. Finally, .A method was developed to determine diflubenzuron in wheat. The residue of diflubenzuron in wheat was extracted by acetonitrile , determined by HPLC equipped with UV detector at 254nm. The sensitivity, accuracy, and precision of the method were investigated. The stability of diflubenzuron in acetonitrile, sample extracting solution, matrix, were also studied in the condition of different storage condition. Using the established method, simultaneous analyzed diflubenzuron, flufenoxuron, and iprodione. The main results were summarized as following.1.The HPLC methodThe determination condition of diflubenzuron by HPLC included Hypersil ODS C18 reverse-phase column: 4.6 mm （i.d.）×250mm,mobile phase:acetonitrile∶water（60/40,v/v）,velocity of flow:1.0 mL/min,wavelength:λ= 254 nm,column temperature:30℃and injector volume:20μL.The LOQ of this method was 0.04mg·kg^-1. The R2 of standard curve of diflubenzuron range from 1 to 400ng was 0.9999.2. The extracted systemExtracting method: The average recoveries from spiked rapeseed extracted by surging and ultrasonic method were respectively 89.37% and 80.60%, the optimal method was surging method.Extracting solvent: The average recoveries from spiked rapeseed extracted by acetone、ethyl acetate、dichloromethane and acetonitrile were respectively 91.27%、72.12%、89.37% and 90.55%,the optimal extracting solvent was acetonitrile. Extracting time: The average recoveries from spiked wheat extracted with surging method by 40、60 and 80min were respectively 68.15%、81.97% and 82.45%, the optimal extracting time was respectively 60min.Extracting times: The average recoveries from spiked wheat extracted by 1, 2 and 3 times were respectively 81.97%、89.37% and 91.26%, the optimal extracting times was 2 times.3. Recovery experiment, sensitivity, accuracy and precision experimentUsing the established method, the average recoveries from spiked wheat with fortified level 0.04mg·kg^-1、0.2mg·kg^-1 and 1.0mg·kg^-1 were 90.25%、89.37%和and 90.87% respectively, the CV were respectively 3.37%、2.37% and 4.15%. The results are all according with the requirement of residual analysis. The minimum detected concentration are 0.04mg·kg^-1.4. The matrix-adaptability experimentThe recoveries of diflubenzuron spiked bean and rice were 88.75% and 90.13% , CV were 3.96% and 2.18%, So this method was fit for analyzing diflubenzuron residue in wheat、bean and rice.5. The stability testThe standard solution of diflubenzuron （dissolved in acetonitrile, diluted with acetonitrile） at 1×10^-6 g/mL can be stored 3 months at least at 4℃; diflubenzuron in extracted solution of wheat can be stored 30 days at -20℃、4℃a nd 25℃; In the condition of -20℃、4℃and 25℃, decompose rate of diflubenzuron in wheat matrix was 2.18%、3.03% and 4.15% after 60 days. 6. The quality-controlling test. The author put up the quality-controlled to the validity and the precision of the analytical method with the results of that the validity-analysis and the precision-analysis were both in the controlled condition and the analytical data were available.7. Superiority of the established method:There are some superiorities including easy to operate, little analytic time, and goodly recurring. At the same time there are good matrix-adaptability and method-adaptability in this method.更多还原