【作者】 王琳玲；

【导师】 陆晓华；

【作者基本信息】 华中科技大学 ， 环境工程， 2008， 博士

【摘要】 样品预处理是环境、食品等复杂样品中痕量有机污染物分析过程中极为重要的步骤。减少或不使用有毒有机溶剂,开发准确、快速、简便且环境友好的绿色样品预处理技术已成为现代分析化学研究的热点之一。近年来以环境友好的水作为萃取溶剂,分别采用加热加压、微波和超声波能量辅助的亚临界水萃取、微波辅助水萃取和超声辅助水萃取等样品预处理技术已逐渐受到广大分析工作者的重视。其中通过加热加压实现的亚临界水萃取技术具有高效、快速、选择性好、操作简便、环境友好等优点,在环境分析中已有广泛应用,但在食品安全快速检测中的应用还较少。微波和超声波具有各自特殊的能量作用模式,能大大提高萃取体系的传质效率,因而将微波和超声作为水萃取的辅助能量,将有利于提高水溶液的萃取速率和萃取效率。对环境和食品等样品中有机污染物残留的分析,采用各种能量辅助水萃取得到的萃取液通常不能直接满足色谱等仪器进样的要求,需要与其他预处理技术联用而实现进一步的净化、富集或溶剂转换等。将溶剂棒微萃取、分子印迹固相萃取等现代绿色预处理技术与能量辅助水萃取技术相结合,将有利于实现各种复杂样品中有机污染物的高选择性、高灵敏度、高效、快速、环境友好的痕量分析。本论文以水作为萃取剂,采用加热加压、微波和超声波等辅助技术,并结合其他绿色预处理技术和仪器检测方法,研究建立了一系列简便、快捷、灵敏、高效、环境友好的以能量辅助水萃取为核心技术的绿色样品预处理方法,并应用于环境和食品等复杂样品中痕量有机污染物的分析。主要研究内容包括:（1）将超声辅助水萃取与溶剂棒微萃取联用,并结合高选择性、高灵敏度的GC-MS检测技术,研究建立了土壤中氯苯的绿色分析新方法。该方法检出限低、回收率高、精密度好、测定速度快、操作简单、绿色环保、成本低,优于传统的索氏提取、浸泡振荡以及溶剂超声萃取等样品预处理技术。土壤中1,2,3-三氯苯、1,2,3,4-四氯苯、六氯苯和1-氯-4-硝基苯的方法检出限分别为1.3、0.7、27.3和1.9μg kg^-1,实际土壤的加标回收率93—105%,相对标准偏差（RSD）1.56—6.29%。（2）以动物饲料样品为对象,采用亚临界水同时萃取其中的土霉素、四环素和氯霉素等多种抗生素,萃取液通过简单过滤后直接进高效液相色谱（HPLC）—紫外（UV）检测,通过对萃取及检测条件的优化研究,建立了一种用于动物饲料中多残留抗生素同时萃取、简便、快速且环境友好的分析新技术。饲料样品中三种抗生素的方法回收率为82.1—90.0%,RSD为1.6—4.8%,优于传统超声萃取技术,满足痕量分析要求。（3）以氯霉素为模板分子,采用沉淀聚合法合成了分子印迹聚合物微球（MIPMs）,并对其合成条件、结合性能及结合动力学等进行了研究和评价。以动物饲料样品中的氯霉素（CAP）残留为分析对象,样品经亚临界水萃取后,采用合成的MIPMs制备的固相萃取小柱进行选择性萃取,固相萃取洗脱液采用HPLC-UV测定。通过各个条件的优化研究建立了一种饲料中氯霉素的简单、快速、高选择性的分析新技术。该技术将亚临界水萃取与分子印迹固相萃取技术相结合,对复杂样品中的CAP具有很好的选择性,可以有效去除萃取液中的杂质组分,从而降低背景干扰,降低检出限,与直接亚临界水萃取后HPLC-UV检测方法相比,方法检出限约为后者的1/10。（4）将亚临界水萃取与快速检测技术相结合,研究建立了蔬菜中灭多威农药的亚临界水萃取-酶抑制法快速检测技术。研究表明,在萃取温度70℃,萃取时间5min,提取液的pH为8.0,提取液体积为5mL的情况下,灭多威有最高萃取效率。分别应用于测定模拟样品和实际样品,结果表明亚临界水萃取的回收率和精密度都要高于国家标准方法中的手摇振荡萃取。（5）以沉积物样品中的2-氯酚（2-CP）、2,4-二氯酚（2,4-DCP）、4-氯酚（4-CP）和五氯酚（PCP）污染物为分析对象,研究建立了以氢氧化钠水溶液作为萃取溶剂的亚临界水萃取（SWE）和微波辅助水萃取（MAWE）两种环境友好的绿色样品预处理方法,并对两种方法的操作条件及分析性能进行了比较。在相同的仪器（GC-μECD）检测条件下,SWE和MAWE两种方法的操作条件和萃取回收率等性能均优于传统的索氏提取及微波辅助溶剂萃取技术,其中SWE采用电炉加热,成本低,操作简单,萃取时间大大低于索氏提取法,但较MAWE长;MAWE采用专门的微波萃取设备,尽管价格贵,但萃取时间很短,操作条件也较容易控制,且对于低浓度氯酚较其他方法具有更好的萃取效率,有利于大批样品的分析测试。将建立的两种方法成功地用于实际沉积物样品中氯酚的测定,获得满意的结果。更多还原

【Abstract】 Extraction,clean-up and preconcetration of the analytes are very important procedures in trace analysis of organic pollutants in complex environment and food samples before instrumental analysis.Recently,the development of accurate,rapid,simple,and environmental friendly sample preparation methods is one of the hot points in modern analytical chemistry.Water,as a cheap and environmental acceptable solvent,is suitable for avariety of sample preparation processes,but water extractions without auxiliary energies are very slow and low efficient.Recently,water extraction assisted by high temperature-high pressure,microwave and ultrasound has been reported in preparation of different samples. These methods have the advantages of time saving,high efficiency,high selectivity,simple and environmental friendly,and thus successfully used in separation of analytes from complex samples.Water extraxtion at high temperature-high pressure,i.e.subcritical water extraction,has been widely applied in environmental analysis,but rarely in the rapid detection of food samples.Water has also been used,although in a minor extent,for microwave and ultrasound assisted extractions,the potential of the energies for assisting water extraction surpasses that of the other conventional auxiliary energy sources.Generally,the extractant of the water extraction can not be injected into the instrument directly without further clean-up,enrichment or solvents exchanging.The combination of auxiliary energies assisted water extraction with other green sample preparation processes, such as solvent bar microextraction and molecular imprinting solid-phase extraction,is beneficial to develop a series of rapid,simple,high selectivity and high sensitivity new analytical methods for determination of trace organic pollutants in complex samples.The objective of this dissertation is to develop a series of new green analytical methods based on the water extraction assisted by auxiliary energies such as high temperature-high pressure;microwave and ultrasound combined with other green sample preparation steps and instrument detection techniques for determination of trace organic pollutants in environmental and food samples.The major contents of this dissertation are described as follows:（1） A novel green analytical method for determination of trace chlorobenzenes in soil samples,based on ultrasound-assisted water extraction combined with solvent bar microextraction and high selective and sensitive GC-MS was developed.Compared with traditional methods,such as Soxhlet extraction,ultrasound assisted solvent extraction and shaking extraction,this method is simpler,cheaper,more rapid and friendly for environment.Under the optimized conditions,the method detection limits for 1,2,3-Trichlorobenzene（1,2,3-TCB）,1,2,3,4-Tetrachlorobenzene（1,2,3,4-TeCB）, Hexachlorobenzen（HCB） and 1-Chloro-4-Nitrobenzene（1-C-4-NB） were 1.3,0.7,27.3 and 1.9μg kg^-1,respectively,and recoveries between 93%and 105%with relative standard deviation ranging between 1.56%and 6.29%were achieved from spiked soil samples.（2） A rapid analytical method for the determination of oxytetracycline（OTC）, tetracycline（TC） and chloramphenicol（CAP） antibiotics in animal feeds has been developed based on subcritical water extraction（SWE） without further sample clean-up followed by high performance liquid chromatography（HPLC） with ultraviolet（UV） detection.Recoveries between 82.1%and 90.0%with relative standard deviations ranging between 1.6%and 4.8%were achieved from spiked animal feed samples by using this method.Compared with the traditional ultrasonic extraction,this procedure was remarkably more efficient in extracting OTC,TC and CAP,simpler to perform,and there was no use of toxic organic solvents.（3） A high selective and simple analytical method for the determination of chloramphenicol（CAP） in animal feeds has been developed based on subcritical water extraction（SWE）,followed by molecularly imprinted solid-phase extraction（SPE） and high performance liquid chromatography（HPLC） with ultraviolet（UV） detection. Molecularly imprinted polymer microspheres（MIPMs） were prepared by precipitation polymerization using CAP as template.The synthetic conditions,kinetics and binding properties of CAP MIPMs were studied.After the evaluation of the selectivity of the CAP imprinted MIPMs,the performance of these materials as SPE sorbents was investigated. Compared with SWE-HPLC method,the SWE-MIPMsSPE-HPLC procedure has higher selectivity and sensitivity,LOD was 0.5μg g^-1,as well as better precision（RSD below 6.0 %） and recovery（＞80%）.（4） A rapid analytical method for the determination of methomyl pesticide in vegetables has been developed based on subcritical water extraction（SWE） and acetylcholinesterase inhibition assay.The optimum extraction conditions were obtained by using 5mL of water（pH=8） as the extractant at 70℃with 5 min static extraction. Compared with manual shaking extraction,subcritical water extraction has higher extraction efficiency and better precision in determination of spiked and real samples.（5） Two environmental friendly sample preparation methods have been developed based on subcritical water extraction and microwave assisted water extraction respectively for determination of 2-chlorophenol（2-CP）,2,4-dichlorophenol（2,4-DCP）,4-chlorophenol （4-CP） and pentachlorophenol（PCP） in sediment samples.Sodium hydroxide solution was used as the extractant in these methods.Under the same instrument（GC-μECD） detection conditions,the operating conditions and the analytical characters of SWE and MAWE both are superior to the traditional techniques,such as Soxhlet extraction and microwave-assisted solvent extraction.SWE use electric cooker to heat,which is cheaper, simpler,and more rapid than Soxhlet extraction.MAWE use of specialized equipment, which is more expensive,but the extraction time is very short,the operating conditions are easier to control,and the extraction efficiency especially for low concentrations of chlorophenols（CPs） is higher than other methods.These methods were applied successfully to the analysis of CPs in real sediment samples.更多还原