【作者】 乔广军；

【导师】 郑建斌；

【作者基本信息】 西北大学 ， 分析化学， 2009， 硕士

【摘要】 离子液体又称室温熔融盐,是由有机阳离子和无机或有机阴离子构成、在室温或邻近温度下旱液态的有机化合物。具有粘度大、电导率高、电化学窗口宽等一系列独特的特性,已成为电化学等诸多领域的研究热点。本论文构置了四种基于新型离子液体修饰电极,研究了两种蛋白质的直接电化学和电催化行为,并建立了多巴胺和抗坏血酸的伏安测定新方法。该研究对于拓宽离子液体的应用范围、丰富电化学的研究内容具有一定的科学意义。全文共分四章,主要研究内容如下:以离子液体1-丁基-3-甲基咪唑六氟磷酸（[BMIM]BF₆）为黏合剂制备了离子液体碳糊基体电极（[BMIM]PF₆-CPE）,采用层层组装技术构置了Nafion/AuNPs/[BMIM]PF₆-CPE,研究了多巴胺（DA）的电化学行为。研究表明,DA在Nafion/AuNPs/[BMIM]PF₆-CPE上出现了一对氧化还原峰,峰电位差ΔE_p=0.129 V,DA在该修饰电极上的电子转移常数k_s=0.71 s^-1;其氧化峰电流与浓度在5.0×10^-7-1.0×10^-5 mol·L^-1范围内呈线性关系,检出限为2.0×10^-7mol·L^-1（S/N=3）,该法用于盐酸多巴胺注射液中多巴胺测定获得了满意结果。构置了基于离子液体1-十四烷基-3-甲基咪唑六氟磷酸([C₁₄mim]PF₆)-壳聚糖（CS）复合物修饰的玻碳电极([C₁₄mim]PF₆-CS/GCE),研究了DA和抗坏血酸（AA）的电化学行为,建立了同时测定DA和AA的伏安新方法。研究表明,在[C₁₄mim]PF₆-CS/GCE上,AA和DA产生的氧化峰完全分开（ΔE_p=0.385 V）,可实现两者的同时测定;AA氧化峰电流与其浓度在2.6×10^-5-1.0×10^-3mol·L^-1范围内呈线性关系,DA氧化峰电流与其浓度在1.3×10^-5-5.2×10^-4mol·L^-1范围内呈线性关系。以离子液体1-丁基-3-甲基咪唑三氟乙酸（[BMIM]TA）-透明质酸（HA）复合膜为固定矩阵,采用滴涂法分别构置了细胞色素c（Cyt c）或肌红蛋白（Mb）修饰的玻碳电极Cyt c-HA-[BMIM]TA/GCE和Mb-HA-[BMIM]TA/GCE,采用电化学方法和光谱法对两种电极进行了研究。结果表明,Cyt c或Mb在[BMIM]TA-HA复合膜内均能保持其生物活性;修饰电极Cyt c-HA-[BMIM]TA/GCE和Mb-HA-[BMIM]TA/GCE在0.1 mol·L^-1 PBS（pH7.0）中均出现了一对准可逆的氧化还原峰。Mb-HA-[BMIM]TA/GCE对H₂O₂具有电催化作用,催化峰电流与H₂O₂的浓度在3.0×10^-6-1.2×10^-4mol·L^-1范围内呈线性关系;Cytc-HA-[BMIM]TA/GCE对H₂O₂具有电催化作用,催化峰电流与H₂O₂的浓度在3.0×10^-6-1.0×10^-4mol·L^-1范围内呈线性关系。更多还原

【Abstract】 Ionic liquids, named as room temperature molten salts, are organic compounds which composed of organic cations and inorganic or organic anions. They are liquds at room temperature or close to room temperature, and have been used widely in electrochemical fields because of their unique electrochemical properties of good conductivity, wide electrochemical windows and high viscosity. In this thesis, four kinds of modified electrodes based on ionic liquid are fabricated and utilized to investigate electrochemical behaviors of two proteins, AA and DA. The new voltammetry methods for determination of AA and DA are established. The studies have scientific significance to expand the application range of ionic liquids and enrich electrochemical research contents. The thesis consists of four chapters. The main contributions are summarized and presented as follows:The ionic liquid 1-butyl-3-methylimidazoiium hexafluorophosphat （[BMIM]PF₆） is used as binder to prepare ionic liquid carbon paste base electrode （[BMIM]PF₆-CPE）. The Nafion/AuNPs/[BMIM]PF₆-CPE is fabricated by layer-by-layer assembly of AuNPs and nafion to investigate the electrochemical behaviors of dopamine （DA）. The results suggest that a pair of redox peaks of DA is observed at Nafion/AuNPs/[BMIM]PF₆-CPE,peak-to-peak separation and the electron transfer rate constant （k_s） of DA are 0.129 V and 0.71 s^-1, respectively. In addition, the peak currents of DA are proportional to its concentrations from 5.0×10⁷ to 1.0×10⁵ mol·L¹ with the detection limit of 2.0×10^-7 mol·L^-1（S/N=3）.The method has been applied to determine DA in the hydrochloride dopamine injection samples and a satisfying result is obtained.The modified glassy carbon electrode ([C₁₄mim]PF₆-CS/GCE) is fabricated by the composite of ionic liquid 1-tetradecyl-3-methylimidazolium hexafluorophosphate ([C₁₄mim]PF₆) and chitosan （CS）. The electrochemical behaviors of DA and ascorbic acid （AA） are investigated at [C₁₄mim]PF₆-CS/GCE. A new method has been established for the simultaneous determination of AA and DA at the modified electrode. The results show that the oxidation peaks of AA and DA can be separated completely （ΔE_p = 0.385 V） at [C₁₄mim]PF₆-Chit/GCE.The peak currents of AA and DA are proportional to their concentrations in a range of 2.6×10^-5-1.0×10^-3 mol·L^-1 and 1.3×10⁵-5.2×10⁴ mol·L^-1, respectively.The composite film is prepared by combining 1-butyl-3-methylimidazolium trifluoroacetate （[BM1M]TA） with hyaluronic acid （HA）. The modified electrodes of Cyt c-HA-[BMIM]TA/GCE and Mb-HA-[BMIM]TA/GCE are fabricated by embedding Cyt c and Mb in the composite film and casting them on the surface of GCE, respectively. The characters of two modified electrodes are investigated using electrochemical and spectrometric methods. The results indicate that Cyt c and Mb can retain their activity in the composite film and realize their direct electrochemistry. Both of the modified electrodes exhibit excellent electrocatalytic activity toward the reduction of H₂O₂.The catalysis current are linear to H₂O₂ concentration in the range of 3.0×10^-6-1.2×10^-4 mol·L^-1 at Mb-HA-[BMIM]TA/GCE and 3.0×10^-6-1.0×10^-4 mol·L^-1 at Cyt c-HA-[BMIM]TA/GCE, respectively.更多还原