【作者】 江改青；

【导师】 操海群；

【作者基本信息】 安徽农业大学 ， 农药学， 2009， 硕士

【摘要】 本文研究建立了小麦植株、籽粒和土壤中苯磺隆与氯氟吡氧乙酸的残留分析方法,评价了方法的准确度、灵敏度和精密度,进行了苯磺隆与氯氟吡氧乙酸在小麦植株和土壤中残留田间消解动态和最终残留试验,为该两种除草剂在小麦地的合理使用提供了科学依据。主要研究结果如下:1.小麦植株、籽粒和土壤中苯磺隆残留分析方法的建立土壤样品以磷酸盐缓冲液-甲醇混合提取,机械振荡提取2次,合并滤液,以SPE柱净化;小麦植株样品以甲醇为提取液,经石油醚液-液分配后再采用SPE柱净化;小麦籽粒样品采用二氯甲烷提取后直接进样分析。采用配有紫外检测器的高效液相色谱仪检测。检测条件:Agilent 1200高效液相色谱仪,具紫外检测器;色谱柱:Agilent ZORBAX-ODS(250mm×4.6mm)色谱柱;检测波长:240nm;流动相:乙腈/0.5%冰乙酸(45/55,v/v);流速:1.0mL/min;柱温:30℃;进样量:20μL。该检测条件下,苯磺隆的保留时间为10.4min,仪器对苯磺隆的最小检出量为1.0×10-9 g。提取体系:比较了机械振荡法和超声波振荡法不同提取时间的提取效率,确定了机械振荡30 min + 15 min为苯磺隆优化后的提取方法;比较了二氯甲烷、甲醇﹑乙腈、0.2 mol/L磷酸盐缓冲液-甲醇(8:2,v/v)等4种提取溶剂对苯磺隆的提取效率,确定了甲醇、二氯甲烷和0.2mol/L磷酸盐缓冲液-甲醇(8:2,v/v)分别为苯磺隆在小麦植株、籽粒和土壤中的提取溶剂。净化方法:采用SPE小柱进行样品的净化处理,比较了土壤样品SPE小柱淋洗液的种类以及配比对净化效果和添加回收率的影响,最终确定先用4mL乙腈pH6.0的0.2mol/L磷酸缓冲液3/7(v/v,85%磷酸调节pH值至6.0左右)将杂质洗脱,再用3mL乙腈- pH7.8的0.2mol/L磷酸缓冲液(1/1,v/v)淋洗,收集淋出液检测。植株样品在基础上,先分别用石油醚和二氯甲烷液液分配萃取后,再经SPE小柱净化。优化后方法的添加回收试验结果表明:在0.01mg/kg~0.80mg/kg添加浓度范围内,小麦植株中苯磺隆的平均回收率为73.1～85.3%,变异系数为5.88～8.53%;土壤中苯磺隆平均回收率为80.1～95.2 % ,变异系数为3.41～7.90% ;在0.025mg/kg~0.80mg/kg添加浓度范围内,籽粒中苯磺隆的平均回收率为73.3～87.5%,变异系数为3.21～6.49%。该残留分析方法的准确性、精确性均达到农药残留分析的要求。2.小麦植株、籽粒和土壤中氯氟吡氧乙酸残留分析方法的建立样品以碱性甲醇混合提取液机械振荡提取后,液液分配净化,采用浓硫酸做为催化剂,甲醇做为衍生化试剂,反应后经石油醚提取,GC-ECD法检测。检测条件的确立:Agilent 6890气相色谱仪具ECD检测器;色谱柱:HP-5毛细管柱(30.0m×250um×0.25um);检测温度:柱温起始温度,70℃,保持1min,以20℃/min至240℃,保持6min;进样口温度250℃,检测器温度300℃;载气:高纯氮气(99.999%),载气流速为1mL/min;进样方式:不分流方式;进样量为2uL。在此条件下氯氟吡氧乙酸的保留时间为10.5 min左右,仪器对氯氟吡氧乙酸的最小检出量为1.0×10-11 g。提取体系:比较了机械振荡法和超声波振荡法两种提取方式不同提取时间的提取效率,确定了机械振荡30min为氯氟吡氧乙酸优化后的提取方法;比较了乙腈、乙酸乙酯、碱性甲醇等3种提取溶剂对氯氟吡氧乙酸提取效率,确定碱性甲醇为氯氟吡氧乙酸在小麦植株、籽粒、土壤中的提取溶剂。衍生化方法:比较了不同甲醇用量、酯化时间和酯化温度等因素对衍生化结果的影响,结果表明,甲醇用量为2 mL,浓H2SO4 1.5 mL,93～98℃水浴条件下酯化时间10 min,较好。优化后方法的添加回收试验结果表明:在0.01mg/kg~0.80mg/kg的添加浓度范围内,小麦植株中氯氟吡氧乙酸的平均回收率为72.3～86.7%,变异系数为3.02～8.59%;籽粒中氯氟吡氧乙酸的平均回收率为77.7～87.3%,变异系数为2.75～7.61%;土壤中的氯氟吡氧乙酸平均回收率为83.6～95.8%,变异系数为2.87～8.46%。该残留分析方法的准确性、精确性均达到农药残留分析的要求。3.小麦植株和土壤中苯磺隆残留消解动态2008年在安徽、山东两地的田间残留试验结果表明,苯磺隆的消解动态符合一级反应动力学方程。在合肥试验点,小麦植株上苯磺隆的田间消解动态方程为C = 0.0593e-0.1393t,半衰期为4.97d;土壤中苯磺隆消解动态方程为C= 0.0434e-0.1250t,半衰期为5.54d。在青岛试验点,小麦植株上苯磺隆的田间消解动态方程为C = 0.0826e-0.1659t,半衰期为4.18d;土壤中苯磺隆消解动态方程为C = 0.0572e-0.1306t,半衰期为5.31d。在合肥和青岛两地最终残留试验的小麦籽粒和土壤样品中均未有苯磺隆检出。4.小麦植株和土壤中氯氟吡氧乙酸残留消解动态2008年在安徽、山东两地的田间残留试验结果表明,氯氟吡氧乙酸的消解动态符合一级反应动力学方程。在合肥试验点,小麦植株上氯氟吡氧乙酸田间消解动态方程为C= 0.1226e-0.1171t,半衰期为5.92d;土壤中氯氟吡氧乙酸田间消解动态方程为C = 0.0861e-0.0828t,半衰期为8.37d。在青岛试验点,小麦植株上氯氟吡氧乙酸田间消解动态方程为C= 0.2149e-0.1368t,半衰期为5.07 d;土壤中氯氟吡氧乙酸田间消解动态方程为C = 0.1478e-0.0893t,半衰期为7.76d。在合肥和青岛两地最终残留试验的小麦籽粒和土壤样品中均未有氯氟吡氧乙酸检出。更多还原

【Abstract】 The analytical methods and dynamics of tribenuron-methyl and fluroxypyr residues in wheat and soil were studied in this dissertation. The sensitivity, accuracy and precision of the methods were investigated. The study provides theoretical reference for using tribenuron-methyl and fluroxypyr properly in wheat field. The main results were summarized as following:1. The analytical methods for tribenuron-methyl residues in wheat plant, wheat seed and soilSoil samples were extracted by mechanical oscillation with mixture of phosphate- buffer and methanol for 2 times, and cleaned up with SPE column; wheat samples extract in methanol, petroleum by liquid-liquid and purification using SPE column; wheat grain samples extracte using dichloromethane. Tribenuron-methyl in samples was determinated by HPLC with UV detector.Determination conditions: Agilent 1200 high performance liquid chromatography equipped with UV, Column: 250mm×4.6mm Agilent ZORBAX-ODS, detector wavelength: 240nm, mobile phases: acetonitrile and 0.5% acetic acid (45:55, v/v), flow velocity: 1mL/min, Oven temperature: 30℃. The retention time of tribenuron-methyl was about 10.4min. The limit of instrumental detection was1.0×10-9 g. Extraction system: Comparing the residue analysis results of tribenuron-methyl with mechanical oscillation and ultrasonic oscillation, we selected mechanical oscillation for 30minutes + 15minutes as the optimized extract method; Comparing the residue analysis results of tribenuron-methyl with dichloromethane,methanol,acetonitrile and 0.2 mol / L phosphate-buffer and methanol (8:2, v / v), we selected methanol ,dichloromethane and0.2 mol / L phosphate-buffer and methanol as the optimized extract solvent respectively in wheat plant、seed and soil.Clean-up system: Identifing SPE column to Clean up in soil ,comparing the purifying effect of elue of the ratio of 1 / 9, 2 / 8, 3 / 7, 1 / 1 (v / v) acetonitrile and pH7.8- 0.2mol / L phosphate-buffer in four of and the recovery rate of Collection of different amounts of acetonitrile and pH7.8 -0.2mol / L phosphate-buffer (1 / 1, v / v), we selected 4mL acetonitrile and pH7.8- 0.2mol / L phosphate-buffer as the optimized elute solvent and collected 3mL acetonitrile and pH7.8 -0.2mol / L phosphate-buffer (1 / 1, v / v). Clean-up of wheat plant on the basis of soil firstly use of 40mL, 30mL petroleum ether to extract and clean up, except for a large number of pigment.The experiments of fortified samples: Four different concentrations of 0.01mg/kg,0.04 mg/kg,0.40mg/kg,0.80mg/kg were fortified respectively in wheat plant and soil,and 0.025mg/kg,0.04mg/kg,0.40mg/kg,0.80mg/kg were fortified in wheat seed. The recoveries of tribenuron-methyl in wheat plant were ranged between 73.1～85.3% , and the CV ranged between 5.88%～8.53%. The recoveries and the CV in soil were ranged between 80.1%～95.2%and 3.41%~7.90%. The recoveries and the CV in seed were ranged between 73.3%~87.5% and 3.21 %~6.49%. This results showed that the method accorded with demands of pesticide residue analysis.2.The analytical methods for fluroxypyr in wheat plant,wheat seed and soil Samples was estracted by mechanical oscillation with alkaline methanol, and cleaned up by liquid-liquid method ,with concentrated sulfuric acid as a catalyst and methanol as the derivatization reagent, after the reaction, the petroleum extracted fluroxypyr .Fluroxypyr in samples was determinated by GC with ECD detector. Determination conditions: Agilent 6890 Gas Chromatography equipped with ECD, Column: 30.0m×250um×0.25um Capillary column, detector temperature was 300℃,injector temperature was 250℃,column program: 70℃for 1min;70℃to 240℃at 20℃/min,240℃for 6min.Carrier gas was Nitrogen at 1 mL/min. The retention time of fluroxypyr was about10.5 min min.The limit of instrumental detection was1.0×10-11 g. Extraction system: Comparing the residue analysis results of fluroxypyr with mechanical oscillation and ultrasonic oscillation, we selected mechanical oscillation for 30 minutes as the optimized extract method. Comparing the residue analysis results of fluroxypyr by different extract solvents of acetonitrile, ethyl acetate and alkaline methanol we selected alkaline methanol as the optimized extract solvent.Clean-up system: Comparing liquid-liquid extraction and solid-phase extraction method , we selected liquid-liquid extraction to clean up. In the alkaline methanol , fluroxypyr salt and dissolve in water, some organic substance retained in organic solvents to abandon in order to achieve the purpose of purification.The experiments of fortified samples: Four different concentrations of 0.01mg/kg,0.04mg/kg,0.40mg/kg,0.80mg/kg were fortified respectively in wheat plant,seed and soil. The recoveries of fluroxypyr in wheat plant were ranged between 72.3%~86.7% , and the CV ranged between 3.02%~8.59%. The recoveries and the CV in seed were ranged between 77.7%~87.3% and 2.75%~7.61%. The recoveries and the CV in soil were ranged between 83.6%~95.8% and 2.87%~8.46%. This results showed that the method accorded with demands of pesticide residue analysis.3.Dynamics of tribenuron-methyl residues in wheat plant and soilThe degradation of tribenuron-methyl in wheat and soil were studied in Hefei and Qingdao. The degradation procedure of tribenuron-methyl and fluroxypyr was correspond to the mathematic pattern. In the wheat plant, the dynamic equation in Hefei was C=0.0593e-0.1393t and half-life was 4.97 d, and the dynamic equation in Qingdao was C= 0.0826e-0.1659t and half-life was 4.18d. In soil, the dynamic equation in Hefei was C= 0.0434e-0.1250t and half-life was 5.54d,and the dynamic equation in Qingdao was C= 0.0572e-0.1306t and half-life was 5.31d. All the final sample was not detected with tribenuron-methyl in Hefei and Qingdao.4.Dynamics of fluroxypyr residues in wheat plant and soilThe degradation of fluroxypyr in wheat and soil were studied in Hefei and Qingdao. The degradation procedure of tribenuron-methyl and fluroxypyr was correspond to the mathematic pattern. In the wheat plant, the dynamic equation in Hefei was C= 0.1226e-0.1171t and half-life was 5.92 d, and the dynamic equation in Qingdao was C= 0.2149e-0.1368t and half-life was 5.07d. In soil, the dynamic equation in Hefei was C= 0.0861e-0.0828t and half-life was 8.37d,and the dynamic equation in Qingdao was C= 0.1478e-0.0893t and half-life was 7.76d. All the final sample was not detected with fluroxypyr in Hefei and Qingdao.更多还原