【作者】 曲云鹤；

【导师】 金利通；

【作者基本信息】 华东师范大学 ， 分析化学， 2010， 博士

【摘要】 随着我国人民生活水平的不断提高,农产品的质量安全问题越来越受到关注,尤其蔬菜中农药残留问题已经成为公众关心的焦点,全国每年都有上百起因食用被农药污染的农产品而引起的急性中毒事件,严重影响广大消费者身体健康。因此,做好蔬菜农药残留检测及防控是当前众多科研工作者关注的热点。农药检测是一项综合性强、涉及面广的任务,目前,应用于有机磷农药检测的方法主要有：色谱法、免疫分析法、生物传感法和速测法等等。本论文旨在探索简便、灵敏、迅速的有机磷农药检测方法并研制实用新型的快速检测仪。基于生物识别的高度专一性和纳米材料对电化学检测信号的放大作用,将生物化学、纳米材料、传感技术三者相结合,构建了新型复合纳米材料修饰的有机磷农药传感器,对有机磷农药进行检测,并探讨了相关的检测机理。同时,利用分光光度原理和酶抑制原理,研制了便携式农药残留速测仪,并对该仪器的检测性能进行评估。全文分两大部分共七个章节,第一部分：农药残留的快速检测方法和仪器的研究,包括第一章到第五章,主要是针对农药残留检测新方法的研究以及新型农药残留仪器的开发研制,作为本论文的主要内容进行综述和研究；第二部分：用于硝基苯类化合物快速检测的新型电分析方法研究和应用,第六章、第七章是在导师的指导下针对爆炸物传感器进行了探索性研究,不作为本论文的主要部分。第一部分：农药残留的快速检测方法和仪器的研究第一章绪论本章综述了我国农药生产使用的现状、农药的种类及其残留危害、现有的农药残留检测技术等等。重点综述了生物传感技术在有机磷农药检测中的应用以及纳米材料在构建生物传感器过程中的特殊作用。在现有的有机磷农药检测技术的基础上,提出了本论文研究的内容和意义。第二章Au-TiO2纳米粒子修饰电极用于有机磷农药对硫磷的直接电化学检测的研究本章工作利用液相沉积法合成了金掺杂的二氧化钛复合纳米粒子(Au-TiO2),以壳聚糖作为交联剂,制备了Au-TiO2复合纳米粒子修饰的电化学传感器,对有机磷农药——对硫磷进行了检测。实验表明,Au-TiO2复合纳米粒子较大的比表面积能够增加对待测溶液中对硫磷的吸附量,提高检测的灵敏度；同时,该复合纳米粒子也促进了电极表面电子传递,加快传感器的响应速度,提高电流响应。所制备的电化学传感器利用示差脉冲伏安法(DPV)在最优条件下对对硫磷进行了检测,检测范围为1.0-7.0x103ng/mL,检测限达到0.5ng/mL(S/N=3)。第三章AChE/PAMAM-Au/CNT/GC传感器用于有机磷农药检测的研究本章工作主要是制备了一种多层AChE/PAMAM-Au/CNT/GC乙酰胆碱酯酶的酶抑制电流型传感器应用于有机磷农药的检测,主要利用碳纳米管良好的导电性和吸附性,以及PAMAM(G4)-Au树枝状复合物特殊的结构及导电性能,利用有机磷农药对乙酰胆碱酯酶的抑制作用,以硫代乙酰胆碱(ATCh)为底物,实现了对有机磷农药的检测。实践表明,该方法快速简单,线性范围宽,灵敏度高。固定在传感器上的乙酰胆碱酯酶具有良好的酶动力学响应,其米氏常数(KMapp)为1.66mmol/L。对有机磷农药呋喃丹的最低检测限达到4.0nmol/L。第四章Tyr/Glu/Fe304/Nafion/CNT/GC酪氨酸酶生物传感器的制备及应用于农药检测的研究本章工作制备了磁性四氧化三铁纳米粒子,采用碳纳米管、Nafion等功能性材料构建了酪氨酸酶(Tyr)生物传感器,并将其应用于农药的检测。实验表明,.四氧化三铁纳米粒子具有良好的生物兼容性,碳纳米管能够有效地促进电子传递,修饰了四氧化三铁纳米粒子等功能性材料的酶传感器,响应速度快,检测灵敏度高,稳定性好；固定在传感器上的酪氨酸酶有良好的酶动力学响应,其表观米氏常数为61.5μmol/L。利用农药对酪氨酸酶的抑制作用,以苯酚为底物,对农药呋喃丹进行了检测,检测限达到2.0×10-9mol/L。第五章便携式农药残留速测仪的研制本章基于酶抑制原理和比色法开发研制了便携式农药残留速测仪,仪器对农药残留的检测具有快速、灵敏、准确等特点,不但可检测水体中残留的农药,而且还可检测瓜果蔬菜中农药的残留量。该仪器具有体积小,携带方便,操作简便,性能稳定,且质量可靠。第二部分：用于硝基苯类化合物快速检测的新型电分析方法研究和应用第六章制备MIP/MWCNTs/GC修饰电极及其在检测DNB中的研究本章结合分子印迹和传感器技术制备用于检测爆炸物、农药和真菌病毒等的新型化学修饰型传感器件,研究被检测物在传感器上的响应机理,制备了具有高灵敏度、低检测限、高选择性和高稳定性的传感器,建立了新的检测方法,为社会应急事件的预警和科学应对提供良好的理论研究基础和有效的检测手段。本文中,成功制备了以二硝基苯(DNB)为模板的分子印迹材料,实现了DNB在材料中的成功嵌入和脱附。而且基于分子印迹技术和化学传感技术,成功实现了两者的优势结合,通过MIP/MWCNTs/GC的研制,有效提高了模板分子DNB的选择性测定。通过该部分工作,为今后进一步开展爆炸物、农药、真菌病毒等的高选择性、高灵敏度检测的新方法、研究打下了一定的理论基础,也初步展示了两者结合后的广泛的应用前景。第七章用于痕量硝基苯类化合物检测的{MSU/PDDA}n/GC纳米修饰电极的研究本章利用层层组装方法,构建了用于水体中TNT等硝基苯类化合物检测的{MSU/PDDA}n/GC纳米修饰电极,以差示脉冲伏安法(DPV)为手段依据TNT、TNB、DNT和DNB等硝基苯类化合物在电极上的电流变化建立了硝基苯类化合物的检测方法,并探讨了反应过程和传感机理。该修饰电极响应速度快、灵敏度高、检测稳定,硝基苯类化合物浓度在4.4×10-9mol/L至1.1×10-7mol/L范围内与电极响应电流呈良好的线性关系。本研究为环境污染分析和爆炸物痕量监测提供了一种新的方法。更多还原

【Abstract】 There are concerns that pesticides used to control pests on food crops are dangerous to people who consume those foods, with the development of people’s living conditions and the improvement of people’s health consciousness. Pesticide residues in food, water and environment are increasing, leading to the contamination and the poisoning of the environment, animals and human bodies. The poisoning incidences caused by pesticide pollution occurred frequently, millions of people suffered from such acute health problems every year. For the sake of human health protection and environmental control, the detection and control of pesticide residues are of tremendous importance.Pesticide detection is some kind of comprehensive, wide range task. Currently, the methods used to determine organophosphate pesticides (OPs) in fruits and vegetables are mainly based on gas chromatography or high-performance liquid chromatography coupled with various detections, immunoassay, biosensors, portable pesticide detection kit and so on. In this paper, we aim to develop a simple, rapid, inexpensive and sensitive analytical method for routine OPs screening in fruits and vegetables, and try to construct a practical instruments for rapid monitoring of pesticide residues. Biochemistry, nanomaterials and sensing technology are combined to establish novel OPs biosensors modified with nanomaterials. The enzymic reactions and electrochemical characteristics of the biosensors are also discussed; on the other hand, a portable OPs detector is designed and fabricated according to the principle of UV-vis spectrophotometer. The dissertation is divided into two parts including seven chapters. The first part includes the first to the fifth chapter which is the main part in the dissertation. The second part includes the sixth and seventh chapter which is the subordinate part in the dissertation.Chapter one:PrefaceIn this chapter, basic knowledge of pesticide is introduced including the employ and production of pesticide in our country, the sorts of pesticides, the harm caused by pesticide residues etc.. Then, the analytical techniques for OPs detections are presented especially the application of biosensor technology which is revolutionized by the nanotechnology. Finally, the work and significance of this dissertation are brought forward.Chapter two:Au-TiO2/Chit modified sensor for electrochemical detection of trace organophosphate insecticidesIn this paper, Au-TiO2/Chit modified electrode was prepared with Au-TiO2 nanocomposite (Au-TiO2) and Chitosan (Chit) as a conjunct. The Au-TiO2 nanocomposite and the films were characterized by electrochemical and spectroscopy methods. A set of experimental conditions was also optimized for the film’s fabrication. The electrochemical and electro-catalytic behaviors of Au-TiO2/Chit modified electrode to trace organophosphates (OPs) insecticides such as parathion were discussed in this work. By differential pulse voltammetry (DPV) measurement, the current responses of Au-TiO2/Chit modified electrode were linear with parathion concentration ranging from 1.0 ng/ml to 7.0×103 ng/ml with the detection limit of 0.5 ng/ml. In order to evaluate the performance of the detection system, we also examined the real samples successfully in this work. It exhibited a sensitive, rapid and easy-to-use method for the fast determination of trace OPs insecticides.Chapter three:Layer-by-Layer self-assembled Acetylcholinesterase/PAMAM-Au on CNT modified electrode for sensing pesticidesIn this paper, an acetylcholinesterase (AChE)/dendrimers polyamidoamine (PAMAM)-Au/Carbon nanotubes (CNTs) multilayer modified electrode based on LbL self-assembled technique was employed in the detection of carbofuran in samples. The configuration of the nanostructure on the electrode provided a favorable environment to the immobilization of AChE. The modified films also improved the electrocatalytic characteristics and electron transfer speed between the films and the surface of electrode. The PAMAM-Au nanoparticles were characterized by SEM and UV-VIS methods. A set of experimental conditions were also optimized for the detection of the pesticides. A linear response over carbofuran concentration in the range of 4.8×10-9M to 0.9×10-7M was exhibited with a detection limit of 4.0×10-9M. The biosensor showed high sensitivity, good stability and reproducibility with promising application.Chapter four:Construction of Tyr/Glu/Fe3O4/Nafion/CNT/GC Biosensor for Detection of PesticideA Tyr/Glu/Fe3O4/Nafion/CNT multilayer modified electrode was employed for the detection of carbofuran in samples. The configuration of the nanostructure on the electrode provides a favorable environment for the Tyr electrocatalytic characterization and fast electron transfer. The surface of the sensor was characterized by TEM methods. A set of experimental conditions were also optimized for the detection of the pesticide.Chapter five:The manufacture of a portable meter for organophosphorus pesticidesA portable meter for the rapid detection of OPs is designed and manufactured based on the inhibition of acetylcholinesterase (AChE). Compared with other existing meters, this one bears a much smaller size which is convenient to carry. A compensated electro-circuit is introduced to the whole circuitry which excludes the influence of light from outside, improving the stability and accuracy of the detector. When applied to the detection of OPs residues in water and vegetable, the meter shows its reliability in result and simplicity in operation.Chapter six:Electrochemical Sensor Prepared from Molecularly Imprinted Polymer for Recognition of 1,3-Dinitrobenzene (DNB)An electrochemical sensor was modified with multi-wall carbon nanotubes (MWCNT) and molecularly imprinted polymer (MIP) material synthesized with acrylamide and ethylene glycol dimethacrylate (EGDMA) in the presence of 1,3-dinitrobenzene (DNB) as the template molecule. The MWCNT and MIP layers were successively modified on the surface of a glassy carbon electrode (GCE), of which the MIP film works as an artificial receptor due to its specific molecular recognition sites. The MIP material was characterized by FT-IR and electrochemical methods of square wave voltammetry (SWV). The interferences of other nitroaromatic compounds (NAC) such as 2,4,6-trinitrotoluene (TNT),1,3,5-trinitrobenzene (TNB) and 2,4-dinitrotoluene (DNT) to DNB were also investigated by the prepared MIP/MWCNT electrode. Compared with other traditional sensors, the MIP/MWCNT modified electrode shows good selectivity and sensitivity. In addition, the current responses to DNB are linear with the concentration ranging from 4.5 X 10-8 mol/L to 8.5×10-6 mol/L with the detection limits of 2.5×10-8 (-0.58 V) and 1.5×10"8 mol/L (-0.69 V) (S/N=3). The construction process of MIP/MWCNT modified electrode was also studied as well. All results indicate that the MIP/MWCNT modified electrode established an improving way for simple, fast and selective analysis of DNB.Chapter seven:{MSU/PDDA}n LBL assembled modified sensor for electrochemical detection of ultratrace explosive nitroaromatic compoundsIn this paper, layer-by-layer{MSU/PDDA}n films assembled by alternate adsorption of mesoporous SiO2 (MSU) and Poly (diallyldimethylammonium chloride) (PDDA) onto a glassy carbon electrode were reported. MSU that we used in this work was synthesized by the precursor of zeolite Y and ionic liquid of 1-hexadecane-3-methylimidazolium bromide (CMIMB), which was used as a template in basic medium. It exhibited larger pore diameter, pore volume and surface area. The electrochemical characteristics of the {MSU/PDDA}n films have been studied by electrochemical impedance spectroscopy in 0.1 M KCl solution containing 5.0 mM Fe(CN)63-/Fe(CN)64-. By differential pulse voltammetry (DPV) measurement, the ultratrace nitroaromatic compounds (NACs) such as TNT, TNB, DNT and DNB can be detected with nM level. The sensitivity for NACs determination in {MSU/PDDA}n films was dependent on the number of layers, pH and ionic strength of electrolyte, based on which a set of optimized conditions for film fabrication was inferred. The current responses were linear with NACs ranging from 10"9 mol/L to 10"7 mol/L with low detection limits. It is a sensitive, rapid and easy-to-use method for the fast determination of NACs.更多还原