论文标题:液相微萃取新技术在农药残留分析中的应用研究
Application of Liquid Phase Microextraction Novel Techniques in Pesticide Residue Analysis
论文作者 郭丽
论文导师 梁沛,论文学位 硕士,论文专业 分析化学
论文单位 华中师范大学,点击次数 127,论文页数 59页File Size2335k
2005-05-01论文网 http://www.lw23.com/lunwen_360089862/ 静态液相微萃取;动态液相微萃取;连续流动微萃取;高效液相色谱;农药残留分析
static LPME; dynamic LPME; continuous-flow microextraction; HPLC;pesticide residue analysis
在农药残留分析中,液液萃取是经典而成熟的样品前处理技术之一,但其具有操作步骤繁多,处理时间长,溶剂用量大等缺点,不但容易损失样品,产生较大误差,而且有毒溶剂的大量使用对操作人员的健康和环境均有影响。因此,高效、快速的无溶剂或少溶剂的样品制备与前处理技术的研究越来越受到分析工作者的关注和欢迎。一些新的萃取技术,如固相萃取、固相微萃取、超临界流体萃取、微波辅助萃取以及浊点萃取因此得到较广泛的应用。 液相微萃取正是在这种情况下兴起的一种新型的样品前处理技术,它是基于被分析物在悬于微量进样器尖端的微滴有机溶剂和样品溶液之间的分配系数不同而进行。它克服了传统液—液萃取技术的诸多不足,仅使用微升级甚至纳升级的有机溶剂进行萃取,适应了现代分析科学的发展要求,是一种集萃取、富集、进样于一体,环境友好的样品前处理新技术。与另一种备受关注的样品前处理技术—固相微萃取相比,由于液相微萃取与高效液相色谱联用不需要特殊的接口,操作简单,因此,引起科学家们更为广泛的关注。自该技术问世至今,已经在环境监测、食品以及生物医药等领域得到广泛的应用。另外,有关其在环境水样中农药残留的应用也有报道,但到目前为止,还没有液相微萃取在有机磷农药分析应用的研究报道。 迄今为止,液相微萃取已所发展了静态、动态、顶空、空心纤维膜以及连续流动微萃取等萃取方式,当萃取基质不同时选择不同的萃取方式。对挥发性特别强的样品,如苯系物,可采用顶空或静态微萃取。对于半挥发性和不挥发性样品来说,当基质比较干净时可采用静态微萃取,而当基质比较复杂时就采用空心纤维膜微萃取。在这几种萃取方式中,有关动态液相微萃取、连续流动微萃取的报道尚不多见。 本论文采用液相微萃取与高效液相色谱法联用分析测定了环境水样中辛硫磷农药残留,取得了很好的萃取效果,说明液相微萃取在农药残留分析方面具有很大的应用前景。主要研究内容有: 1、采用静态液相微萃取技术与高效液相色谱-二极管阵列检测器相结合,
In the screening of pesticide residues in water samples, liquid-liquid extraction (LLE) is the classical method for pesticide extraction and preconcentration, but it is time-consuming tedious, laborious and requires large amounts of toxic organic solvents, which have a great threaten on human health and environmental protection. Therefore, solvent-free extraction as a promising technique for sample preparation and pretreatment has become one of the most important research areas in modern analytical chemistry and attracted much attention recently. Such extraction techniques as solid phase extraction (SPE), supercritical fluid extraction (SFE) , microwave-assisted extraction (MAE), cloud point extraction (CPE) and solid phase microextraction have been widely applied in various fields.More recently, efforts have been placed on miniaturizing the LLE extraction procedure by greatly reducing the solvent to aqueous phase ratio, leading to the development of liquid-phase microextraction (LPME) methodology. LPME is based on the distribution effect of the analytes between a microdrop of organic solvent at the tip of a microsyringe needle and aqueous sample solution. In LPME, analytes were extracted from small volume of samples to only microlitre even nano-litre organic solvents. This technique belongs to the green analytical technique and is suitable to the development of micromation of modern analytical science. It combines extraction, preconcentration and sample introduction in one step, and proved to be a simple, fast and low-cost sample preparation method. Compared with SPME, LPME has gained increasing attention, due to the special interface is needless when it combines with high performance liquid chromatography(LPME). Since the method was first introduced in 1996, LPME has been successfully applied for the application of environmental monitoring, food analysis, biological and medical analysis. Although the use of LPME in pesticides analysis with gas chromatograph has been described previously, to our knowledge, it has not been used for the analysis of organophosphorous insecticides.Up to now, several different models of LPME have been developed, such as static LPME, dynamic LPME, hollow fiber membrane LPME, headspace LPME and continuous-flow microextraction (CFME). When it comes to different sample solutions, different models of LPME can be used. Analytes with high volatilities can be extracted by headspace or static LPME. For analytes with weak volatilities, static LPME can be used when the sample solution has clean background, otherwise hollow fiber membrane LPME can be used. According to our knowledge, among those several models, dynamic LPME and CFME are relative novel LPME methods, both of which have seldom been reported.In this study, the static LPME, dynamic LPME and CFME techniques have been applied for the extraction of Phoxim, respectively. Parameters relevant to the extraction performance, such as extraction solvent type, solvent drop size, extraction time and salt addition, were studied and optimized. The optimized method was applied to determine phoxim in lake water and tap water to evaluate the application of this method to real samples.
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