【作者】 臧晓欢；

【导师】 王志；

【作者基本信息】 河北农业大学 ， 食品科学， 2008， 硕士

【摘要】 传统的样品前处理技术如液液萃取、固相萃取、沉淀和过滤等,存在操作繁琐耗时,需要使用大量的对人体和环境有毒或有害的有机溶剂等缺点。分散液相微萃取是2006年提出的一种新型样品前处理技术,一次萃取过程仅需十几微升有机溶剂,是一种对环境友好的样品前处理方法。该方法具有集采样、萃取和浓缩于一体,操作简单、快速、成本低且富集效率高等优点。本文第一部分综述了目前农药残留分析的研究现状和农药残留分析中样品前处理技术的最新进展。对各种样品前处理技术进行了概述并比较了不同前处理方法的优缺点。详细介绍了分散液相微萃取技术的操作过程及其在分析领域的应用。本文第二部分将分散液相微萃取(DLLME)与气相色谱.电子捕获检测(GC-ECD)相结合,建立了高灵敏度、快速测定水样中7种拟除虫菊酯类农药残留的新方法。对萃取有机溶剂和分散剂的种类及其用量、萃取时间的长短等影响分散液相微萃取富集效率的条件进行了优化,在优化试验条件下,7种拟除虫菊酯类农药的富集倍数高达708～1087倍。以α-六六六为内标,7种拟除虫菊酯类农药在0.8～600μg/L范围内具有良好的线性关系,线性相关系数(r)在0.9990～0.9999之间。7种拟除虫菊酯类农药的检出限在0.10～0.04μg/L(S/N=3:1)范围内。该方法已应用于自来水、井水与河水等实际水样的分析,平均加标回收率在76.0%～116.0%之间,相对标准偏差在3.1%～7.2%之间。本文第三部分建立了运用DLLME-GC-ECD技术灵敏、快速分析苹果样品中克菌丹、灭菌丹和敌菌丹3种杀菌剂残留的新方法。并对影响分散液相微萃取富集效率的诸因素进行了优化,在优化条件下该方法对3种杀菌剂的富集倍数可达824～912倍。3种杀菌剂检出限在6.0～8.0μg/kg(S/N=3:1)范围内,以α-六六六为内标,3种杀菌剂在10～100μg/kg范围内具有良好的线性关系,线性相关系数(r)在0.9996～0.9999范围内。苹果样品中两个添加水平(20.0μg/kg和70.0μg/kg)的平均加标回收率分别为96.0%～103.0%和96.7%～99.1%,相对标准偏差在4.4%～5.9%之间。该方法简便、快速、准确,应用于苹果实际样品中杀菌剂残留的测定取得了满意的结果。本文第四部分应用DLLME-GC-ECD技术建立了测定葡萄样品中百菌清、克菌丹和灭菌丹残留的新方法。并对影响萃取富集效率的试验条件逐一进行了优化,在优化条件下,3种杀菌剂的富集倍数可达788～876倍,检出限在6.0～8.0μg/kg(S/N=3:1)范围内,以α-六六六为内标,测定3种杀菌剂的线性范围为10～150μg/kg,线性相关系数(r)在0.9990～0.9995范围内。该方法已成功应用于葡萄实际样品中杀菌剂残留的测定,平均加标回收率在92.3%～106.1%之间,相对标准偏差在4.5%～7.2%之间。测定结果令人满意。更多还原

【Abstract】 Conventional sample preparation methods, such as liquid-liquid extarction and solid phase exrtaction, are time- and solvent- consuming and often involve several complicated procedures. In 2006, Assadi and co-workers developed a novel liquid-phase microextraction technique, named dispersive liquid-liquid microextraction (DLLME). The method is based on the use of a ternary component solvent system. The advantages of DLLME method are environmental friendliness, simplicity of operation, rapidity, low-cost, high-recovery and high enrichment factor.In the first part of this thesis, the progress of the analytical methods for pesticides and sample pre-treatment technologies are summarized. A detailed review concerning the development of DLLME and its applications are presented.In the second part, a novel method for the determination of pyrethroid pesticide residues in water samples by dispersive liquid-liquid microextraction (DLLME) coupled with capillary gas chromatography with electron capture detection (GC-ECD) was developed. Some important parameters that influence the extraction efficiency, such as the kind of the extraction and disperser solvent, their volume and the extraction time, were investigated. Under the optimum conditions, as high as 708 to 1087-fold enrichment factors were achieved. Usingα-benzene hexachloride as the internal standard, a good linear relationship was obtained in the range of 0.8～600μg/L of the analytes with the correlation coefficients (r) of 0.9990～0.9999 and the detection limits of 0.10～0.04μg/L (S/N= 3:1), depending on compounds. This method has been successfully applied for the determination of pyrethroid pesticide residues in real water samples (tap water, well water and river water) with satisfactory results. The recoveries ranged from 76.0% to 116.0% and the relative standard deviations fell between 3.1% and 7.2 %.In the third part, a new method was developed for the determination of fungicides in apples by DLLME coupled with GC-ECD. Some experimental parameters that influence the extraction efficiency were studied and optimized to obtain the best extraction results. Under the optimum conditions, high enrichment factors were achieved ranging from 824 to 912 for the compounds. The recoveries of fungicides in apples at spiked levels of 20.0μg/kg and 70.0μg/kg were 96.0%～103.0% and 96.7%~99.1%, respectively. The limits of detection were in the range between 6.0 and 8.0μg/kg (S/N =3:1). The linearity of the method ranged from 10 to 100μg/kg for the three fungicides, with the correlation coefficients (r) varying from 0.9996 to 0.9999. The obtained results showed that the DLLME combined with GC-ECD could satisfy the requirements for the determination of fungicides in apple samples.In the fourth part, a simple and rapid dispersive liquid-liquid microextraction technique (DLLME) coupled with capillary gas chromatography with electron capture detection (GC-ECD) was developed for the extraction and analysis of fungicides from grape samples. Some important parameters that affect the extraction efficiency of DLLME, i.e., the type of extraction solvent, the kind and volume of disperser solvent, extraction time, were studied systematically. Under the optimum conditions, the enrichment factors and extraction recoveries were ranged between 788~876 and 92.3%～106.1%, respectively. The linear range was 10～150μg/kg and the limits of detection were between 6.0 and 8.0μg/kg (S/N = 3:1) for the three fungicides, with the correlation coefficients (r) varying from 0.9990 to 0.9995. Some grape samples were successfully analyzed using the proposed method.更多还原