【作者】 宋金春；

【导师】 胡先明；

【作者基本信息】 武汉大学 ， 有机化学， 2012， 博士

【摘要】 70年代中期化学修饰电极逐渐发展形成一个比较活跃的研究方向，是电分析化学和电化学的前沿领域，目前已应用于材料科学、生命科学、分析科学、环境科学等许多方面。电极表面修饰的介质材料可在电极表面的电子传递过程实现电催化反应，加速氧化还原中心，它广泛应用于各种难以实现的电子传递过程，例如：有机物的电催化、生物分子的电催化、无机离子的电催化等。有很多化学修饰电极的制备方法，而且种类各异，本论文针对化学修饰电极的制备及在药物分析领域中的应用展开了以下研究：1.在疏水性表面活性剂存在下，乙炔黑纳米颗粒被均匀地分散在水中，并采用滴涂法制备得到乙炔黑修饰玻碳电极。芦丁在该电极上的电化学行为显示这种修饰材料能极大提高芦丁的电化学响应信号，对芦丁的电化学检测有明显的增敏作用。基于这一现象，采用该纳米乙炔黑修饰电极，建立了一种灵敏、简便的芦丁电化学检测新方法，其线性范围为20μg L^-1-500μg L^-1，检测限为10μg L^-1。最后，此方法还成功用于多种含芦丁中药材芦丁含量的测定。2.通过化学氧化石墨粉末，制备出表面积大、具备大量含氧功能团的石墨烯（GO）纳米颗粒，并将制备的石墨烯纳米颗粒均匀分散在水中，制备得到GO纳米颗粒修饰的玻碳电极。利用该电极研究对乙酰氨基酚电化学行为，发现石墨烯薄膜对对乙酰氨基酚有明显的富集作用，能显著提高对乙酰氨基酚的氧化信号。基于这一现象，建立了一种灵敏、简便、快速测定对乙酰氨基酚的新电化学方法。富集1分钟后，其检测限达到50μg L^-1（微克每升），并最后将此方法用于化药片中对乙酰氨基酚含量的测定。3.按文献报道方法合成了一种介孔SiO₂材料，然后制备出介孔SiO₂修饰碳糊电极、研究了5-羟基色氨酸（5-HT）在裸碳糊电极和介孔SiO₂修饰碳糊电极上的电化学行为。接过显示由于介孔SiO₂具备大的比表面积、特殊的介孔结构以及强的吸附能力，因而介孔SiO₂修饰电极对5-羟基色氨酸的氧化有明显的增敏效应，显著提高5-羟基色氨酸的电化学氧化信号。通过考察支持电解质种类、介孔SiO₂用量、富集时间等参数对5-羟基色氨酸氧化信号的影响，获得了最佳的测试条件，建立了一种灵敏、快速、简便的测定5-羟基色氨酸的电化学分析新方法。该方法的线性范围为2.0×10^-7-1.5×10^-5mol L^-1，富集2分钟后的检出限为6.0×10^-8mol L^-1。10支介孔SiO₂修饰碳糊电极平行测定10次的相对标准偏差（RSD）等于6.7%，表明该方法重现性良好。最后，将此方法还成功用于人血清中5-HT的检测。4.通过电化学聚合的方法，制备了一种测定微量雌二醇的聚L-丝氨酸薄膜修饰电极。利用该修饰电极研究了雌二醇的电化学行为，发现雌二醇在聚L-丝氨酸膜修饰玻碳电极上的氧化峰电位较在裸玻碳电极上明显负移，且氧化峰电流显著提高，表明聚L-丝氨酸膜对雌二醇的氧化有催化作用。基于这些现象，本实验采用该修饰电极建立了一种灵敏、快速、简便的雌二醇电化学检测方法，检测限达到2.0×10^-8mol L^-1。最后，将建立的方法成功用于人血清中雌二醇含量的测定。更多还原

【Abstract】 The chemically modified electrodes have been one of the most burgeoning andflourish research areas in the electrochemistry areas and electroanalytic chemistry sincethey were developed in the middle of1970’s．It has been widely applied in many areassuch as material science， life science， analytic science and environmental science.The mediators modified on the electrode could be used to catalyse the electrochemicalreaction f and acilitate the electron transfer，which couldn’t be realized easily, like theelectrocatalysis of organic compounds，biomolecules and inorganic jons．Differentmethods and materials have been used for the modification of electrodes in this workand the appllication of the electrodes prepared is also evaluated.The main works we have done in this thesis include：1. Acetylene black nanoparticles were homogeneously dispersed into water in thepresence of hydrophobic surfactant and then used to modify the surface of a glassycarbon electrode. An examination of the electrochemistry of rutin showed that thismodification of the electrodes resulted in a considerable enhancement of the surface,thus remarkably increasing the signal for rutin. As a result, a sensitive and convenientelectrochemical method was developed for the determination of rutin. The linear rangeis from20μg L^-1to5mg L^-1, and the limit of detection is10μg L^-1. The method wassuccessfully employed to the determination of rutin in traditional Chinese medicines.2. The graphite oxide （GO） was prepared via the chemical oxidation of naturalgraphite powder, and then used to modify the surface of glassy carbon electrode （GCE）.The electrochemical behavior of acetaminophen was examined. In0.01mol L^-1HCl, anirreversible oxidation peak is observed for acetaminophen, and the peak currentremarkably increases at the GO film-modified GCE. The influences of supportingelectrolyte, amount of GO suspension, accumulation potential and time were studied onthe oxidation peak current of acetaminophen. As a result, a new electrochemical methodwas developed for the detection of acetaminophen. The linear range is from25μg L^-1to4mg L^-1, and the limit of detection is6μg L^-1based on three signal-noise ratio. Finally,it was successfully used to detect acetaminophen in tablets.3. A mesoporous SiO₂was synthesized according to the published work, and thenused to modify the carbon paste electrode （CPE）. The electrochemical behaviors of5-hydroxytryptamine （5-HT） at the bare CPE and the mesoporous SiO₂modified CPE were compared. Owing to the huge surface area, unique mesopores and strongadsorptive ability, the oxidation signal of5-HT at the mesoporous SiO₂modified CPEgreatly increased, compared with that at the bare CPE. This clearly suggests that themesoporous SiO₂modified electrode shows efficient and remarkable enhancementeffect towards5-HT. Based on this, a sensitive, rapid and convenient electrochemicalmethod was developed for the determination of5-HT after optimizing the experimentalparameters such as supporting electrolyte, content of mesoporous SiO₂as well asaccumulation time. The linear range is from2.0x10^-7to1.5x10^-5mol/l, and the limitof detection is as low as8.0x10^-8mol/l after2-min accumulation. The relative standarddeviation （RSD） for10mesoporous SiO₂modified CPEs is evaluated to be6.7%.Finally, this novel method was successfully used to determine5-HT in human bloodserums.4. A thin film of poly（L-serine） was prepared via electropolymerization for thedetermination of trace levels of estradiol. In pH5.0phosphate buffer, L-serine wasoxidized during the cyclic potential sweeps between-0.60and2.0V, forming a thin filmat the electrode surface. The electrochemical behavior of estradiol was investigated. Theoxidation peak potential of estradiol shifts negatively at the poly（L-serine） film-coatedglassy carbon electrode （GCE） compared with that at the bare GCE. Otherwise, theoxidation peak current greatly increases at the poly（L-serine） film-modified GCE. Thesephenomena suggest that the poly（L-serine） film exhibits catalytic activity towards theelectrochemical oxidation of estradiol. Based on this, a sensitive, rapid and simpleelectrochemical method was proposed for the determination of estradiol. The limit ofdetection is evaluated to be2.0x10^-8mol L^-1. Finally, this method was successfullyused to determine estradiol in blood serum.更多还原