【作者】 李月秋；

【导师】 陈冠华；

【作者基本信息】 河北农业大学 ， 农产品加工及贮藏工程， 2004， 硕士

【摘要】 建立了甲基对硫磷的胶束电动毛细管色谱（MECC）常规检测方法。讨论了碳酸氢钠浓度、十二烷基硫酸钠浓度及pH值对柱效的影响。在最佳条件下，运行缓冲液中碳酸氢钠浓度为15mmol/L，十二烷基硫酸钠浓度为40mmol/L，pH为10.3。此方法用于市售乳油中甲基对硫磷含量的测定，并进行了回收率试验。样品5次测定的RSD在0.34％～0.79％之间，回收率在101.88％～104.76％之间。 Sweeping是应用MECC模式实现的样品柱上富集技术，它可以用于中性分析物的浓缩。Sweeping方法可以改进毛细管电泳的检出限。基于此，本文建立了甲基对硫磷的毛细管电泳Sweeping柱上富集检测新方法，用以检测蔬菜等实际样品中残留的甲基对硫磷。研究了胶束浓度、电解质浓度、pH、有机溶剂添加剂浓度、样品稀释溶液浓度、电压、进样压力及毛细管长度等因素对富集倍数的影响，优化的测定条件为：内径50μm的毛细管总长为50cm，有效长度为45.4cm；样品用0.5mmol/LNaH₂PO₄进行稀释配制。运行缓冲溶液中十二烷基硫酸钠浓度为180mmol/L，磷酸二氢钠浓度为20mmol/L，pH6.2，甲醇添加量为10％（V：V）。运行电压为7kV，采用压力进样方式，进样压力为2062.5kPa×s。在上述确立的试验条件下，甲基对硫磷获得了100.38倍富集，检出限达到了0.0814mg/kg。在GB/T5009.20-1996建立的样品提取及净化方法的基础上，讨论了向样品的丙酮及二氯甲烷混合液中添加活性碳净化色素等杂质对分析物回收率的影响。结果表明，对回收率没有明显的影响。在上述国标方法的基础上，增加活性碳净化步骤，作为样品前处理方法。方法用于市售洋白菜、油菜、韭菜、黄瓜、西红柿5种蔬菜样品中甲基对硫磷残留量测定，同时进行了回收率试验，回收率在92.42％～92.53％之间。 建立了对硫磷的毛细管电泳Sweeping柱上富集检测新方法，用以检测蔬菜等实际样品中残留的对硫磷。研究了胶束浓度、电解质浓度、pH、有机溶剂添加剂浓度、样品稀释溶液浓度、电压、进样压力及毛细管长度等因素对富集倍数的影响。优化的测定条件为：内径50μm的毛细管总长为50cm，有效长度为45.4cm；样品用0.3mmol/LNaH₂PO₄进行稀释配制。运行缓冲溶液中十二烷基硫酸钠浓度为120mmol/L，磷酸二氢钠浓度为20mmol/L，pH6.2，甲醇添加量为30％（V：V）。运行电压为7kV，采用压力进样方式，进样压力为2406.25kPa×s。在上述确立的试验条件下，对硫磷获得了107.58倍富集，检出限达到了0.1150mg/kg。在GB/T5009.20-1996建立的样品提取及净化方法的基础上，讨论了向丙酮及二氯甲烷混合液中添加活性碳净化色素等杂质对回收率的影响。结果表明，对回收率没有明显的影响。在上述国标方法的基础上，增加活性碳净化步骤，作为样品前处理方法。方法用于市售洋白菜、油菜、韭菜、黄瓜、西红柿5种蔬菜样品中对硫磷残留量测定，同时进行了回收率试验，回收率在90.7％～90.82％之间。更多还原

【Abstract】 A method of micellar electrokinetic capillary chromatography (MECC) with usual injection was developed for the determination of Methyl parathion. The effects of the concentration of NaHCOa and sodium dodecyl sulfate and the pH of running buffer on the efficiency of column were discussed. So the optimum conditions were as follows: NaHCOs concentration of 15mmol/L, sodium dodecyl sulfate concentration of 40mmol/L and pH10.3 in running buffer. The method has been applied to the determinations of Methyl parathion concentrates in its emulsifiable solution purchased from the market. The relative standard deviation of 5-run-determinations to methyl parathion were 0.34%~0.79%, and the recovery of them were 101.88%~ 104.76%, respectively.Sweeping is an on-line sample concentration technique in MECC, which can concentrate neutral substances. Sweeping can improve detection limit of capillary electrophoresis. A new method to determine residual methyl parathion in fresh vegetable by capillary electrophoresis was reported based on sweeping principle. The effects of the concentration of micellar, electrolyte and organic additive in running buffer, pH, the concentration of solution to dilute sample, voltage, injection pressure and the length of capillary on enhancement factor were studied.So the optimum conditions were as follows: A 50-um-i.d.capillary with a50-cm total length and 45.5-cm effective length was used to determine sample diluted by 0,5mmol/L NaH2PO4. The concentration of SDS, NaH2PO4 and methanol in running buffer was 180mmol/L, 20mmol/L, 10%(V: V), respectively. The pH of buffer was 6.2, and the run-voltage was 7kV. Pressure injection model was used and injection pressure was 2062.5 kPaxs. Under the experimental conditions above mentioned, enhancement factor of 100.38 was acquired and detection limit was 0.0814mg/kg for methyl parathion. In order to remove impurities such as pigment from sample, activated carbon was added to the solution of vegetable sample that was extracted and cleaned-up by the method of GB/T 5009.20-1996. The obvious effect of the addition of activated carbon on the recovery of methyl parathion was not found. So it was determined as the further clean-up method that activated carbon was added to the vegetable sample solution. The method has been applied to the determinations of residual methyl parathion in cabbage, rape, leek, cucumber and tomato that werebought in the market. The recovery of them were 92.42%~ 92.53%.A new method to determine residual Parathion in fresh vegetable by capillary electrophoresis was reported based on sweeping principle. The effects of the concentration of micellar, electrolyte and organic additive in running buffer, pH, the concentration of solution to dilute sample, voltage, injection pressure and the length of capillary on enhancement factor were studied. So the optimum conditions were as follows: A 50-um-i.d.capillary with a 50-cm total length and 45.5-cm effective length was used to determine sample diluted by 0.3 mmol/L NaH2PO4. The concentration of SDS, NaH2PO4 and methanol in running buffer was 120mmol/L, 20mmol/L, 30%(V: V), respectively. The pH of buffer was 6.2, and the run-voltage was 7kV. Pressure injection model was used and injection pressure was 2406.25 kPa xs. Under the experimental conditions above mentioned, enhancement factor of 107.58 was acquired and detection limit was 0.1150 mg/kg for Parathion, In order to remove impurities such as pigment from sample, activated carbon was added to the solution of vegetable sample that was extracted and cleaned-up by the method of GB/T 5009.20-1996. The obvious effect of the addition of activated carbon on the recovery of Parathion was not found. So it was determined as the further clean-up method that activated carbon was added to the vegetable sample solution. The method has been applied to the determinations of residual Parathion in cabbage, rape, leek, cucumber, tomato that were bought in the market. The recovery of them were 90.7%~90.82%.更多还原