【作者】 焦琳娟；

【导师】 张桃芝；

【作者基本信息】 华中师范大学 ， 分析化学， 2004， 硕士

【摘要】 农药残留量分析的第一个环节就是从样品中提取和净化痕量农药，以便进行分析测定。提取的好坏直接影响到分析结果的正确性。目前残留农药分析经常使用的方法，如薄层色谱、气相色谱、液相色谱、色谱—质谱联用等，均要求样品净化处理，否则大量杂质的存在不仅会干扰残留农药的分析，而且还会损坏仪器。因而提取、浓缩和净化是农药残留分析中一个十分重要的前处理步骤。液液萃取(LLE)是一种成熟的复杂样品前处理技术，大约70％的农药残留分析现在仍采用LLE进行样品前处理。近年来，农药残留分析方面出现了许多新的样品前处理技术，如加速溶剂提取(ASE)、微波协助提取(MAE)、固相萃取(SPE)、超临界流体萃取(SFE)、膜萃取、固相微萃取(SPME)、一滴溶剂萃取(SDE)等，这些方法都有各自的优势和缺陷。本学位论文采用一滴溶剂萃取分析水体、蜂蜜中的有机氯农药并与液液萃取、固相微萃取两种前处理技术进行对比。 第一：根据文献对一滴溶剂萃取(SDE)在色谱分析方面的发展作了综述。研究了一滴溶剂萃取一气相色谱直接进样一电子捕获检测器(SDE—GC—μ ECD)分析检测水体中八种有机氯混合农药(α—666、β—666、γ—666、δ—666、P，P′—DDE、P，P′—DDD、O，P′—DDT、P，P′—DDT)的可行性。对影响一滴溶剂萃取效率的萃取溶剂、萃取时间、萃取温度、搅拌速度、溶剂体积、水样体积以及离子强度进行了优化。在优化后的实验条件下，该方法除了对P，P′-DDD的线性范围在0.4-4.0 ng／mL之间，其余的七种目标物线性范围均在0.04-4.0ng／mL之间，相关系数R 0.9976-0.9999，回收率范围为77.6％-104％，标准偏差为1.3％-13.1％。检出限(LOD)六六六为20.2ng／L，滴滴涕为121ng／L。SDE还与传统的LLE、先进的SPME进行对比，结论是SPME的准确度、精密度最高；LLE的检出限最低。但是，优化后的SDE在相同的浓度范围内有更好的线性关系；同时还具有操作简单快速、溶剂使用量极少和省钱的优点。虽然SDE检出限比LLE差，但能满足国家标准的要求。因此，本实验所建立SDE-GC-μ ECD检测水体中有机氯农药残留方法是简单快速、经济廉价、准确可行的。吧泛一二之___T烹之2二二二二匕:竺叮二泛，二了气丁_二二吮二竺几几t二节二一二‘兀了了一一一二二气布一1叮一之_二厂二尸 第二:研究了一滴溶剂萃取一气相色谱直接进样一电子捕获检测器(S DE一GC一乒ECD)分析检测蜂蜜中八种有机氯混合农药的可行性。在优化后的实验条件下，该方法除了对P，P’一DDD的线性范围在0.4一long/mL之间，其余的七种目标物线性范围均在0.1一10ng/mL之间，相关系数R在0.9974一0.9999，回收率范围为81.4%一93.9%，标准偏差为2.5%一22.8%。检出限:六六六为41ng/L，滴滴涕为141ng/L。与SPME相比，优化后的SDE在检测蜂蜜中有机氯农药残留时不仅可忽略蜂蜜溶液中基体的干扰，省去样品净化过程，而且还具有降低滴滴涕的检出限和省钱的优点。虽然在准确度、精密度方面sDE比SPME略差，但仍然在方法容许的范围内。因此，本实验所建立SDE一GC一p ECD检测蜂蜜中有机氯农药残留方法是简单快速、经济廉价、准确可行的。关键词:有机氯农药一滴溶剂萃取固相微萃取液液萃取 水体蜂蜜更多还原

【Abstract】 The first step of retention analysis is to extract and clean up the trace pesticides. It has a direct effect on the accuracy of results. At present, the common methods, for example, Thin-film Chromatography, Gas Chromatography, Liquid Chromatography and Gas Chromatography-mass spectrum, require analyzing purer samples. The complicated matrixes will interfere with the retention analyses and damage the instruments. So sampling, concentration and purification are important preparation steps in the retention analyses of pesticides. Liquid-liquid extraction is a typical and traditional method of preparation that deals with complicated samples. Now it is still used in 70% of retention analyses of pesticides. Recently, lots of new techniques of preparation have appeared, such as Acceleration Solution Extraction (ASE), Microwave Assisted Extraction (MAE), Supercritical Fluid Extraction (SFE), Solid Phase Extraction (SPE), Solid Phase Microextraction(SPME), Liqud-Liquid Microextraction(LLME). These techniques have respective advantages and shortcomings. This thesis adopts the method of Single Drop Extraction to analyze organochlorine pesticides in water and honey samples and compares it with Liquid-Liquid Extraction and Solid Phase Microextraction.In the first place ,this thesis summarizes the development of One Drop Extraction in the field of chromatography and studies the possibility of the joint use of Single-Drop Extraction-Gas Chromatography-ECD to detect in water eight mixed organochlorine pesticides, namely, -666, -666, -666, -666, P, P’ -DDE, P, P’ -DDD, O, P’ -DDT, P, P’ -DDT. Factors that affect the efficiency of One Drop Extraction such as extractive solvents, extractive time, extractive temperatures, stirring speed, solvent volume, water sample volume and ionic strength are optimized. Under these conditions, the linear range of seven target samples is from 0.04 to 4.0ng/ml except for P,P’ -DDD, with its linear range from 0.4-4.0 ng/mL and the relative coefficient is from 0.9976-0.9999.The recoveries arefrom 77.6%to 104%, and the standard deviations are from 1.3% to 13.1%. The LODs of 666 and DDT are 20.2ng/L and 121ng/L separately. Compared with LLE and SPME, SPME is highest in accuracy and precision. Though LLE has the lowest LOD, the optimized SDE is fast and higher in linearity and requires little solvent. Though the LOD of SDE is higher than that of LLE, it can meet the demands of the national standards. So the SDE-GC- ECD method established in this experiment is a fast, economical and reliable way to detect the residue of organochlorine pesticides in water samples.Secondly, this thesis studies the possibility of the joint appliance of Single-Drop Extraction-Gas Chromatography-ECD to analyze and detect eight mixed organochlorine pesticides in honey samples. Under optimized lab conditions, the linear range of seven target samples is from 0.1 to 10 ng/ml except for P,P’ -DDD, with its linearity ranging from 0.4-10 ng/mL and the relative coefficient is from 0.9974-0.9999. The recoveries are from 81.4% to 93.9%, and the standard deviations are from 2.5% to 22.8%. The LODs of 666 and DDT are 41ng/L and 141ng/L separately. Compared with SPME, the optimized SDE, when used to detect residue of organochlorine pesticides in honey samples, can not only dismiss the influence of background and the purification process, but also lower the LOD of DDT. This method can also reduce cost. Although the accuracy and precision of the method are a bit lower than those of the SDE or the SPME, they are within the permitted ranges. So the SDE-GC- ECD established in this experiment in detecting residue of organochlorine pesticides in honey is rapid, inexpensive and reliable.更多还原