【作者】 易军；

【导师】 弓振斌；

【作者基本信息】 厦门大学 ， 海洋化学， 2002， 硕士

【摘要】 复杂体系痕量组分的快速分离和准确测定是当今分析化学家面临的重要而艰巨的任务，其重要研究内容之一是食品中残留的危及人身健康的痕量农药成分分析。食品中农药的残留量一般在10^-6 -10（-9） （w／w）或更低的水平，这就要求发展简单、快速、有效的样品制备与前处理方法，以及具有高灵敏度和选择性的检测方法。茶叶是一种公认的健康食品，同时又是一味传统中药，药食同源。随着人们生活水平的提高，越来越多的人认识到茶叶保健与防治疾病的功效，茶叶以其简便、省时的优点越来越受到人们的青睐。与此同时茶叶的卫生质量问题（包括农药残留、重金属以及有害细菌三个方面）也逐步受到人们关注。尽快建立和完善茶叶及茶叶制品中农药残留检测的方法，已成为刻不容缓的任务。茶叶中农药残留检测的方法已有报道，但存在的问题主要有两个方面，一是在样品的预处理过程中使用较多如苯、甲苯、三氯甲烷等易对环境造成污染的有机溶剂；二是整个分析流程过长，主要是样品制备过程花费了整个流程60％以上的时间，而且在仪器测试阶段，往往只能检测一个或几个性质相似的农药残留组分，使得实际样品检测的时间过长，尤其是在原料收购以及成品检验环节，从而限制了这些方法的应用。本工作针对这一突出的问题，研究并建立茶叶中农药残留的多组分快速检测方法，以满足相关行业对农药残留检测的需求。本论文共分三部分：第一章为相关工作的背景及文献综述；第二、三、四、五章为论文的重点，分别为茶叶中农药残留快速分析的气相色谱法、高效液相色谱法，以及农药残留样品分析的预处理技术和茶叶中有机磷与有机氮农药残留测定的初步研究结果；第六章为建立方法的实际应用，并 摘 要对福建省以及全国茶叶生产中农药残留现状及问题进行了分析。 第一章为文献综述，主要介绍了超声波振荡、固相攀取等常用的前处理方法和超临界流体革取、固相微摹取、微波辅助革取、凝胶渗透色谱。基质固相分散革取、加速溶剂革取等无（或少）溶剂前处理技术以及这些方法在食品中农药残留分析中的应用，本并对气相色谱、高效液相色谱和生物测定等分析检测方法进行了简单概述。 第二章建立了以正己烷／丙酮为混合提取液，采用摇床振荡提取，氟罗里硅土／活性炭混合柱柱层析和石油醚和乙酸乙酯（9：l，v／v）为洗脱液的方法净化待测样品，最后用 HP－5毛细管柱分离、电子捕获检测器（ECD）检测的气相色谱法测定茶叶中六六六、滴滴涕、三氯杀螨醇和菊酯类农药残留的分析方法。比较了用不同提取方法提取茶叶样品中待测组分所得的得率，以及净化条件的优化。整个分析流程的时间大约为4小时，样品在六六六、DDT、三氯杀螨醇加标浓度为0～20ng／mL，菊酯类农药加标浓度为 0～100ng／mL范围时，方法回收率为 72．3～100刀％，能够满足茶叶中痕量农药残留组分分析测试需要。 第三章采用摇床振荡提取，混合微柱柱层析净化，以 Hypersil ODS柱（250mm X 4．0。X SPin）为分离柱，DAD检测器的 HPLC法测定茶叶中氰戊菊酯和氯氰菊酯残留，样品前处理过程同第二章相似。通过优化流动相配比及流速条件，综合分析时间、峰形、灵敏度等影响因素，选择乙睛与水的比例为74：26、流速为1二mL／min。在该实验条件下，将氯氰菊酯和氰戊菊酯混合标准样品进行三维空间扫描，确定吸收波长为 198urn。建立了高效液相色谱法测定茶叶中氰戊菊酯及氯氰菊酯的方法。 第四章探讨了超声波振荡法应用于茶叶中有机氯及菊酯类农药待测组分的提取方法。将超声波振荡提取与摇床振荡提取的结果相比较，研究了超声波频率、超声时间对提取的影响。拟定了用超声振荡提取、气相色——l厦门人学学位论文 ws谱法测定茶叶中多种农药残留的方法。 第五章初步研究了茶叶中有机磷及有机氮农药残留的气相色谱测定方法。通过实验比较选定丙酮提取茶叶中甲胺磷、乙酚甲胺磷和优乐得三种目标物、用活性炭脱色、GC－NPD方法测定了样品中的三种农药残留。方法初步研究结果表明，样品中添加的标准农药组分可定量回收，回收率为89．5～94．0％。实验的初步结果预示该方法很有可能成为一个较理想的茶叶中有机磷以及优乐得测定的新方法。 论文最后概述了我国和福建省茶叶中农药残留现状，简要分析了茶区农残成因以及茶叶中农药残留的主要污染来源，作为所建立方法的实际应用，近一年来用建立的方法对福建省茶叶产区的实际样品进行了分析，实际样品检测结果为：六六六合格率 100％，DDT合格率 97％，三氯杀螨醇合格率 46％；而拟除虫菊酯类农药除了联苯菊酯（合格率为 98％）其余三种超标严重，氰戊菊酯超标率为幻％，甲氰菊酯超标率为 97％，氯氰菊酯超标率为 100％。所得实验数据与目前我国出口茶叶农药残留趋势相吻和。更多还原

【Abstract】 The presence of pesticide residues in foodstuff such as Chinese tea is an escalating problem that has aroused public concern over potential health hazards. Analytical techniques such as gas chromatography (GC), high performance liquid chromatography (HPLC), and GC mass spectrometry (MS) allow for the accurate determination of pesticide residues in tea samples. However, they require sophisticated procedure for sample preparation before analyzing so as to remove or eliminate the effects from matrices. Ordinary methods for sample preparation, such as soxhlet extraction (SOX) and liquid-liquid extraction (LLE), often are time- and solvent-consumed. Ultrasonic extraction (USE), solid phase extraction (SPE), supercritical fluid extraction (SFE), and microwave-assisted extraction (MAE) have been found more and more applications in analysis of pesticides residues. In this work, we concentrated ourselves on development of simple, rapid and accurate methods for analysis of pesticides residues in Chinese tea by novel GC and HPLC techniques.This dissertation consists of three parts. The first chapter summarized the progress of pesticides residues analysis in foodstuff. The second part is the main body of the thesis including Chapter 2, 3, 4, and 5, in which a procedure for rapid analysis of BHC, DDT, dicofol and pyrethroids in tea by GC was proposed. A method for determination of cypermethrin and fenvalerate in tea by HPLC was also proposed in this part. Preliminary studies for sample preparation with ultrasonic extraction and determination of organophosphatesby GC with nitrogen phosphorus detector (NPD) were also described in this part. The third part is application of developed methods in the analysis of real world tea sample.The first chapter mainly introduces some commonly used sample preparation methods and their applications in the analysis of pesticide residues. These methods include ultrasonic extraction (USE), solid phase extraction (SPE), supercritical fluid extraction (SFE), solid phase micro-extraction (SPME), microwave aided extraction (MAE), gel permeation chromatography (GPC), matrix solid phase dispersion (MSPD) and accelerated solvent extraction (ASE).In the second chapter, an optimized procedure was proposed to rapidly analyze the residues of BHC, DDT, dicofol and pyrethroids in Chinese tea by GC with electron capture detector (BCD). The pesticide residues were extracted with a mixture of H-hexane and acetone (97.5:2.5, v/v) on a novel shaker at 40-42癈. The analytes were purified by a column (70mm x 5mm) packed with about 320 mg florisil and top packed with 28mg active carbon. Petroleum ether mixed with acetic ether (9:1, v/v) was selected to elute the residues from column. After extraction and purification, analyses of BHC, DDT, dicofol and pyrethroids were carried out by capillary gas chromatography with GC-ECD. Recoveries of all pesticides in spiked sample ranged 72.3~100.0%.In the third chapter, a method for analysis of cypermethrin and fenvalerate in Chinese tea by HPLC with diode array detector (DAD) was proposed. Thesteps for pesticide residues extraction and purification are similar with that in Chapter 2. The mobile phase is a mixture of acetonitrile and water (76:24, v/v) at flow rate of 1.2 mL-min. Maximum absorbance was found at 198 nm for both pesticides. Recoveries for cypermethrin and fenvalerate in spiked sample are 71% and 76%.The fourth chapter reported preliminary study of the application of USE in analysis of BHC, DDT, dicofol and pyrethroids in Chinese tea by GC-ECD. Experiment results show that USE can extract the analyte targets with efficiencies of around 100% compared with that of novel shaker used in Chapter 2. The results also show that extraction efficiency varies for different pesticide residues. Preliminary investigation indicated USE is an alternative for pesticide analysis in Chinese tea with GC-ECD.Chapter 5 starts a new investigation for rapid analysis of organophosphates in Chinese tea by GC-NPD. Acetone was selected as extraction solvent. Anal更多还原