【作者】 王春燕；

【导师】 田坚；

【作者基本信息】 长春理工大学 ， 材料物理与化学， 2011， 博士

【摘要】 化学修饰电极(CMEs)是通过人为地对电极表面进行分子设计,将具有优良化学性质的分子、离子和聚合物等固定在电极表面,使电极具有特定的化学和电化学性质,以便在其上进行所期望的反应。CMEs丰富了电化学的电极材料,扩展了电化学的应用范围,是目前最活跃的电化学和电分析化学的研究领域之一。本研究的目的在于发展和完善CMEs,寻找新的修饰剂,研究新技术和新方法,探索聚合物薄膜CMEs在分析领域的应用,提高其检测的灵敏度和选择性,建立可应用于实际样品的检测技术。本研究工作的创新点是利用电化学聚合法制备了聚氨基黑10B修饰电极、聚铬黑T修饰电极及聚谷氨酸修饰电极,并成功地应用于一些电活性物质的快速、简便、经济的检测。本研究主要内容表现在以下几个方面：1.聚氨基黑lOB/Nafion修饰电极的制备及对多巴胺的检测弱酸性染料氨基黑10B的结构中含有大的共轭芳香环,通过π-π键作用可使其在玻碳电极表面有一定程度的物理吸附,但这一过程吸附量少且易受环境影响,难以控制。以玻碳电极为基底,首次采用电化学聚合的方法将氨基黑10B染料分子非共价修饰到玻碳电极表面,然后滴加Nafion,制备了聚氨基黑10B/Nafion修饰电极。该电极制作过程非常简单,修饰量可以通过电化学聚合圈数进行控制,同时具有良好的稳定性和重现性。利用SEM和AFM可以观察到聚氨基黑10B薄膜紧密均匀地附着在玻碳电极表面。通过对修饰电极进行电化学阻抗谱实验和电化学表征,表明该修饰电极具有更快的电子转移速度和更大的有效电活性表面积。该修饰电极不仅对多巴胺有良好的电催化作用,而且有效地排除了抗坏血酸的干扰,提高了选择性。该电极可用于多巴胺盐酸注射液和小牛血清中多巴胺的测定,为药剂中多巴胺的测定提供了一种新方法。2.聚氨基黑10B修饰玻碳电极检测维生素B6利用电化学聚合的方法将氨基黑10B染料分子修饰到玻碳电极表面,制备的聚氨基黑10B修饰电极稳定性和重复性较好,克服了碳电极暴露面敏感的缺点。计时库仑实验结果表明该修饰电极正逆反应均可在瞬间反应完毕,电极表面的氧化还原反应及膜与裸电极的电子交换速率均很快。该修饰电极对维生素B6的氧化有明显的电催化作用。利用微分脉冲伏安和安培检测技术分析维生素B6,线性范围宽,检测限低(5.0×10-8mol/L),低于已报道的其他方法。而且,该修饰电极具有制备简单、响应快、稳定、重现性好等优点。该电极用于药物制剂中维生素B6浓度的测定,获得了满意的结果。聚氨基黑10B修饰电极有望应用于药物分析领域。3.聚铬黑T修饰电极检测亚硝酸盐铬黑T是一种常见的酸碱指示剂,其分子中含有多个共轭体系,可能起到媒介体作用,但以此物质作为电极修饰剂的研究报道很少。利用电化学聚合法将铬黑T修饰到玻碳电极表面,得到聚铬黑T修饰电极。铬黑T在玻碳电极上的电化学聚合过程属于自由基引发电化学聚合过程。聚铬黑T修饰电极对亚硝酸盐的还原有较强的电催化作用,这种催化作用主要是由于聚铬黑T薄膜与带负电荷的亚硝酸盐离子的静电相互作用,导致亚硝酸盐离子富集在电极表面/溶液界面,从而提高检测的灵敏度。通过优化亚硝酸盐电化学响应的实验参数,该修饰电极可用于亚硝酸盐的安培检测,线性范围跨越6个数量级,检测限达到1.0×10-8mol/L。同时,该修饰电极制备简单,重现性和稳定性良好,可以连续使用两周而信号无明显降低。将该修饰电极用于泡菜中亚硝酸盐的测定,获得了满意的结果。4.聚谷氨酸修饰电极的制备及同时检测对苯二酚和邻苯二酚利用电化学聚合的方法制备得到聚谷氨酸修饰玻碳电极。AFM结果表明聚谷氨酸在玻碳电极表面上以类似纳米纤维状的形式存在,多个聚谷氨酸链凝聚呈现出聚合网状结构,这种结构有利于检测物与聚合物膜内带相反电荷离子的相互作用。该修饰电极对对苯二酚和邻苯二酚的电化学氧化还原显示出很高的催化能力,显著降低了二者的氧化电位,改善了二者的电化学可逆性,同时增强了二者的氧化还原峰电流。利用循环伏安和微分脉冲伏安技术,实现了对苯二酚和邻苯二酚的同时检测,并且具有较高的灵敏度。此外,我们将聚谷氨酸修饰电极用于实际废水中对苯二酚和邻苯二酚的测定,得到了满意的结果,有一定的潜在应用价值。更多还原

【Abstract】 The aim of chemically modified electrodes (CMEs) is to carry out the molecular design on the electrode surface. In other words, to immobilize molecular, ion and polymer on the electrode surface and make the electrode specially chemical and electrochemical properties, so anticipant reactions can occur on its surface. CMEs make the electrode material abundant and enlarge its application in electrochemistry. Now, it has been of most active fields in electrochemistry and electroanalysis chemistry.This dissertation was concentrated on the use of various polymer materials and modification methods to prepare polymer modified electrodes and investigate their characterization and analytical application. The preparations of poly(amino black 10B) modified electrode, poly(eriochrome black T) modified electrode and poly(glutamic acid) modified electrode have been evaluated. Their micrographs, structure, properties and applications have been investigated by scanning electron microscopy (SEM), atomic force microscope (AFM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), differential pulse votammetry (DPV) and amperometric detection (AD). The main points of this dissertation are summarized as follows:1. Determination of dopamine on a poly(amino black 10B)/Nafion modified electrodeAmino black 10B is a weak acid dye with a large conjugate aroma ring, so it can be adsorbed physically on the surface of glass carbon electrode (GCE) byπ-πaction. But the capacity of physical adsorption is too hard to be controlled due to its poor adsorption and inherent unstable. To solve this problem, we prepared a modified electrode by electrochemical polymerization of amino black 10B on GCE, and covered by a film by Nafion. This poly(amino black 10B)/Nafion modified electrode is very sensitive and stable. The modification thickness can be controlled by electrochemical polymerization circles. The poly(amino black 10B) film was characterized by SEM, AFM and EIS. The electrode developed showed an excellent electrocatalytic ability towards dopamine oxidation. The redox peak current of dopamine increased linearly with the concentration in the range of 2.0×10-7～3.0×10-5 mol/L, and the detection limit (S/N=3) was 1.0×10-7 mol/L. Moreover, the modified electrode avoided the interference of ascorbic acid and exhibited good reproducibility. The modified electrode can be used for the determination of dopamine in the injections and serum with good recovery and reproducibility.2. Determination of vitamin B6 on a poly(amino black 10B) modified electrodeA poly(amino black 10B) modified electrode was fabricated by electrochemical polymerization of amino black 10B on GCE. The modified electrode shows good electrocatalytic activity to the oxidation of vitamin B6. DPV and AD were developed for the direct measurement of vitamin B6 with high sensitivity (5.0×10-8 mol/L). The modified electrode has many advantages such as fast response, good reproducibility, low cost and fabrication simplicity. The practical application of this modified electrode was demonstrated with vitamin B6 drugs determination3. Determination of nitrite on a poly(eriochrome black T) modified electrodeA poly(eriochrome black T) modified electrode was fabricated by electrochemical polymerization and was used to electrochemically determine nitrite. Due to the electrostatic interaction between the negatively-charged nitrite ions and poly(eriochrome black T) film, the poly(eriochrome black T) modified electrode exhibited enhanced electrocatalytic properties towards the reduction of nitrite, observing an improved peak current. The electron transfer coefficient is 0.735. The poly(eriochrome black T) modified electrode exhibited fast response towards nitrite with a detection limit of 1.0×10-8 mol/L and a linear range of 1.0×10-8～1.0×10-3 mol/L. The possible interferences from several common ions were tested. The developed modified electrode was also successfully applied to the determination of nitrite in pickle sample.4. Simultaneous determination of hydroquinone and catechol with poly(glutamic acid) modified electrodeGCE was modified with poly(glutamic acid) films by electrochemical polymerization of glutamic acid monomer. Poly(glutamic acid) films showed good adherence to the electrode surface. AFM images showed a fibres polymeric network film, allowing a high electron transfer. The performance of the modified electrode was characterized by CV and EIS. Poly(glutamic acid) modified electrode showed an excellent electrocatalytic ability towards the redox of hydroquinone and catechol, and a decrease of the overpotential and the improvement of the redox peak current was observed. Hydroquinone and catechol could be simultaneously analyzed on the modified electrode by CV and DPV techniques. Moreover, the modified electrode exhibited good reproducibility and long-time stability. It was successfully used to analyze hydroquinone and catechol in waste water samples.更多还原