海水莠去津检测电位型传感器系统研制 | |
高奇 | |
学位类型 | 硕士 |
导师 | 秦伟 ; 刘铭平 |
2014-05-26 | |
学位授予单位 | 中国科学院研究生院 |
学位授予地点 | 北京 |
学位专业 | 环境工程 |
关键词 | 分子印迹 固相萃取 聚合物膜离子选择性电极 海水 莠去津 |
摘要 | 随着我国工农业生产的加速发展,海岸带环境污染问题日趋严重。近年来,由于海水受有机物污染导致大批鱼虾贝类死亡的事故不断发生,有机污染物检测已引起人们广泛关注。莠去津是一种重要的三嗪类除草剂,由于其具有价格便宜、除草效果好、保留时间长等优点在农业生产中被普遍使用。然而,研究表明莠去津具有类雌激素作用,可造成致畸、致突变等严重后果,进入水体可抑制水生植物的光合作用,并通过食物链进入动物和人体,诱发多种疾病。因此,开发海水中莠去津的快速、灵敏、准确的检测方法具有重要的现实意义。 由于海水样品成分复杂、基体效应大且污染物含量很低,因此要求检测方法具有良好的选择性和较高的灵敏度。目前,通用的海水莠去津的检测方法是将大体积海水样品带回实验室,然后进行繁琐的分离富集,最后通过大型设备(如GC-MS)完成样品分析。这种检测手段不仅耗费了大量的人力、物力和财力,而且在时间尺度上不便于深入研究这些污染物在海水中的环境地球化学行为。因此,目前急需发展在线快速检测技术及便携式分析设备,能够对海岸带水体中的莠去津进行动态的检测,从而获得在时间和空间尺度上的大量的实时数据。基于此,本文将流动分析在线样品过滤及分离富集等自动化预处理技术与低检出限聚合物膜离子选择性电极电位检测技术进行有机结合,开发出一类能够在线快速检测海岸带水体中莠去津的新型电位型传感器及便携式样机。该样机不仅能够为及时快速地开展海洋环境监测和评价提供良好的研究平台,而且有利于全面深入研究莠去津在海岸带环境中的迁移及转化规律,为海洋中莠去津的综合整治和健康风险评价提供科学依据。具体研究内容如下: 1. 分子印迹固相萃取前处理方法的构建:由于海水中有莠去津的含量很低且海水基体效应大,因而进行检测前首先需要对目标物加以分离富集。本文以莠去津为模板分子、以MAA为功能单体、EGDMA为交联剂合成了其分子印迹聚合物,并将其作为固相萃取的高选择性吸附剂,解决了传统固相萃取填料如C18、硅胶等选择性差的问题。通过优化分子印迹聚合物合成条件、填料用量、洗脱剂的种类、上样流速和洗脱流速等,实现了对模拟海水中莠去津的高效分离富集,回收率在93%~103%之间。 2. 莠去津分子印迹电位型传感器的构建:聚合物膜离子选择性电极是一种常见的电位型传感器,它具有设备简单、价格低廉、较准确、易于小型化和一体化等优点,特别适合于在线分析检测。分子印迹聚合物具有构效预定性、特异识别性和广泛实用性等特点,可显著提高分析方法的灵敏度和选择性且具有很强的稳定性,是聚合物膜离子选择性电极在环境污染物监测应用中的理想离子载体。本文采用合成莠去津分子印迹聚合物作为聚合物膜离子选择性电极的高选择性载体,通过调控电极内充液的组成,并使用旋转圆盘电极降低了电极的检出限,成功实现了莠去津的高灵敏电位检测。在最佳膜组成条件下,该电极对莠去津的检出限可达1.7×10-8 mol/L(3σ),线性范围在1.0×10-7~8.0×10-7 mol/L,对常见无机离子具有较好的选择性。 3. 海水中莠去津在线快速检测传感器系统的构建及检测样机的开发与应用:我们采用分子印迹固相萃取实现对海水中莠去津的高效分离富集,以分子印迹聚合物膜为传感器敏感元件实现了对有机分子莠去津的高灵敏电位检测,结合在线过滤等流动分析自动化处理技术,提高传感器体系的响应性能与分析效率,开发出一类能够快速检测海水中莠去津浓度的新型电化学传感器及便携式样机系统。所开发样机线性范围在5×10-10~4×10-9 mol/L,检出限为9×10-11 mol/L(3σ),并最终成功应用于海水实体样品。 |
其他摘要 | With the rapid development of China's industry and agriculture, coastal pollution problems are becoming more and more serious. In recent years, a large number of fish, shrimps and shellfish are dead, due to the organic pollutants in seawater. As a result, the detection of organic pollutants in seawater has attracted considerable attentions. Atrazine, as a typical herbicide, has been widely applied in the agricultural production, because of its low cost, better efficiency and longer retention time. However, atrazine is one kind of endocrine disrupters, which can cause deformity and mutation. It can not only inhibit the photosynthesis process of aquatic plants, but also cause a variety of diseases in animals and humans through the food chain subsequently. Therefore, it is of importance and practical significance to develop a rapid, sensitive and accurate method for detecting atrazine in seawater. Due to the complex composition of seawater, large matrix effect and low concentrations of organic pollutions, the analytical methods with excellent selectivity and high sensitivity are needed in order to detect organic pollutions. At present, the commonly used method for the detection of atrazine in seawater is that a large amount of seawater is collected in glass bottles and sent to the lab, then pretreated with separation and enrichment processes, and finally detected by large-scale equipment (such as GC-MS). However, this method not only costs lots of manpower, materials and financial resources, but also is not suitable for further studying the environment geochemical behaviors of these organic pollutants in the time scale. Therefore, it is urgent to develop on-line and rapid detection technology and portable analytical equipment. Here, we combine the automated pretreatment technology with polymeric membrane ion-selective electrodes to develop a potentiometric sensing system and a portable prototype. The proposed system can not only provide a good platform for monitoring and evaluation of the marine environment, but also be useful to study the migration and transformation of atrazine in the coastal environment. The contents are as follows: 1. Molecularly imprinted solid-phase extraction (SPE) for sample separation and preconcentration: Due to the low amount of atrazine and large matrix effect in seawater, a separation and enrichment pretreatment process is required before detection. Here, the atrazine molecularly imprinted polymer (MIP) is synthesized using MAA as the functional monomer and EGDMA as the cross-linker and used as highly selective sorbents for solid-phase extraction, which may overcome the problem of the poor selectivity of the conventional SPE materials (C18 and silica gel). By optimizing the synthesis conditions for the molecularly imprinted polymer, the amount of MIP, the eluent and the flow rates of sampling and elution, the efficient separation and enrichment of atrazine in seawater could be obtained by using the prepared molecularly imprinted SPE column and the recoveries are 93%~103%. 2. Potentiometric sensor based on the molecularly imprinted polymer for determination of atrazine: Polymeric membrane ion-selective electrode (ISE) is a common class of potentiometric sensors. Its instrument is simple, cheap and reliable. It is easy to be miniaturized and integrated, which is especially suitable for on-line analytical determination. MIPs could significantly improve the selectivity of the analytical methods, due to their features, such as structural predetermination and specific recognition. Therefore, MIPs have been widely used as ionophores. In this paper, the atrazine ISEs have been developed based on atrazine MIP dispersed in the ion-selective membrane. The adjustment of the composition of the inner filling solution and the application of the rotating electrode were used to low the detection limit of the electrode. Under the optimum composition of the membrane, the electrode shows a potentiometric response in the linear range of 1.0×10-7~8.0×10-7 mol/L atrazine and the detection limit is 1.7×10-8 mol/L (3σ). The proposed electrode shows an excellent selectivity over common inorganic ions. 3. Potentiometric sensing system for rapid detection of atrazine in seawater: In this work, atrazine MIP is used as the SPE sorbent for separation and enrichment of atrazine and as ionophores for specific recognition of atrazine, respectively. Online sample filtration and the flow analysis are used in order to improve the performance and efficiency of the sensor system. The portable prototype system has been developed for the rapid and sensitive detection of atrazine in seawater. The linear range of the detection prototype is 5×10-10~4×10-9 mol/L and the detection limit is 9×10-10 mol/L (3σ). The proposed system has been successfully applied to detect atrazine in seawater. |
语种 | 中文 |
文献类型 | 学位论文 |
条目标识符 | http://ir.yic.ac.cn/handle/133337/6851 |
专题 | 中国科学院烟台海岸带研究所知识产出_学位论文 |
推荐引用方式 GB/T 7714 | 高奇. 海水莠去津检测电位型传感器系统研制[D]. 北京. 中国科学院研究生院,2014. |
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