三种苯脲类除草剂高效液相色谱分析方法及其环境行为研究

【作者】 赵进英；

【导师】 李金昶；

【作者基本信息】 东北师范大学 ， 分析化学， 2003， 硕士

【摘要】 农药的大量使用，现已对全世界的环境和人类身体健康造成了重大的危害。苯脲除草剂是我国最常用的除草剂。由于它们有一定的毒性和致癌性，在土壤中能存在一个季度左右。因此，对它们在水、土壤中的残留状况进行分析研究有实际意义。 固相萃取技术（SPE）是近些年来发展起来的样品处理方法。它具有操作简单、省时、安全、溶剂用量少、不易乳化以及高富集因子等优点，广泛应用于痕量有机物的分离富集。 本论文简要介绍了固相萃取的基本原理、富集装置及影响萃取效率的因素和在环境分析中的应用及发展趋势，介绍了固相萃取新技术。 获得的主要研究结果如下： 1．对高效液相色谱测定条件进行了优化。通过试验确定：分析柱为ODS柱，检测波长为250nm，流动相为甲醇／水=60∶40（v／v），流速为0.7mL/min，柱温为35℃。 2．选定C₁₈相作为富集水样中苯脲除草剂的固定相。研究了影响方法回收率的诸多因素，优化了固相萃取条件。选定四氢呋喃为洗脱剂；洗脱剂的用量为1.5mL；向水样中加入1％甲醇作为改性剂可加大苯脲除草剂的回收效果；样品以5mL/min的流速通过萃取柱较为合适；水样的pH值基本上对苯脲除草剂的回收率没有影响；水样中氯化钾的质量浓度为10g/L。并对此作了理论上的探讨。 3．通过研究三种苯脲除草剂在水体中的降解状况得知，水解速率与温度和pH值有关。在太阳光照下，在纯水中光解速率较慢，丙酮加速光解；而在紫外灯下光解速率很快，只有几个小时。 4．研究了三种苯脲除草剂在长春地区四种典型土壤中的吸附状况。结果表明，影响吸附的主要因素是有机碳含量。从有机碳吸附常 摘 要数看，利谷隆具有“中等移动性”，灭草隆、敌草隆具有“较高移动性”，说明它们在土壤中的迁移性较差。 5．检测了三种除草剂在实际水样中的残留状况。固相革取有效地消除了杂质的干扰。测定结果的精密度和准确度都很好。更多还原

【Abstract】 With the use of a lot of pesticides, there was harm to human being’s health and the environment in the world. Phenylurea herbicides were the common herbicides in our country. They were persistent in the soil a quarter of a year and highly carcinomatous. Therefore, the analysis into their persistence in the water and the soil were of great importance.Solid phase extraction (SPE), as a sample pretreatment technique was developed in the recent years. It had the advantage of analytical speed, simplicity, low costs, safety, no emulsification, flexibility and high preconcentration factor, and was used to separate and preconcentrate lots of organic analytes.This article totally described the development, principle, performing procedure, devices and the factors influencing process and recovery of SPE. Its applications in environmental analysis were also well reviewed. Furthermore, the detection methods and its trend were summarized. Finally the new techniques of solid phase extraction were outlined.The main conclusions were as follows:1. The best chromatographic conditions were UV detection wavelength of 250nm, mobile phase of methanol/water at 60/40(v/v), mobile phase flow rate of 0.7mL/min, column temperature of 35 , the column used was ODS, were used to determine the phenylurea herbicides in the environment.2. C18 was selected as the best solid phase for extracting trace phenylurea herbicides in water samples. In addition, most of the influencing factors were studied and optimized. The result showed that tetrahydrofuran was the preferred elution solvents for the absorbed phenylurea herbicides. When the elution solvent (1.5mL) was selected, the variation of recoveries as a function of the volume of elution solvent used can be determined. The addition of l%methanol into the sample prior to spiking could greatly improve the recoveries. The flow rate of sampleloading was 5mL/min. The acid of samples had no influence on the recoveries. Meanwhile, the concentration of potassium chloride in the water was 10 g/L. What’s more; these were discussed in the theory.3. The degradation of the three phenylurea herbicides was investigated in the water. The results showed that hydrolysis of these three phenylurea herbicides depended on both pH and the temperature. The rate of photo degradation in the water under sunlight was very slow, when acetone was added, the rate was fast. However, the rate of photo degradation was much faster than those, when it was under UV lamp, only several hours.4. Research on the adsorption of the three phenylurea herbicides in four different types of soil in Changchun region showed that the content of organic carbon was the major factor of adsorption in the soil. From the organic carbon adsorption constant, linuron had middling transference, diuron and monuron had upper transference, and these showed that they had worse transference in the soil.5. In the analysis of real samples such as surface run-off water, Solid phase extraction technique enabled the elimination of matrix interference and the work was possible.更多还原