【作者】 于浩；

【导师】 郑建斌；

【作者基本信息】 西北大学 ， 分析化学， 2007， 博士

【摘要】 以化学修饰电极为基础的各种电化学传感技术是电化学及电分析化学研究的热点领域之一。在制备电化学传感器的诸多修饰材料中，以普鲁士蓝为代表的多核金属铁氰化物以其良好的化学和电化学稳定性，丰富的电化学性质在包括催化、电化学传感器、功能材料、电色装置、离子识别、固态电池和分子磁性等领域得到了广泛的应用。从分析化学的角度看，通过改进制备方法进一步改善这类化合物修饰电极的电化学性质，电催化活性及稳定性以提高其分析测试性能；进一步拓宽这类化合物在电催化领域及生物电化学传感方面的应用是目前该领域研究的主要问题之一。本论文分别采用电化学沉积法、两步溶胶凝胶法等多种方法制备了包括PB、GaHCF、ZrHCF、CuHCF、SnHCF及5种镧系稀土元素LaHCF、CeHCF、PrHCF、ErHCF和TbHCF共10种金属铁氰化物修饰电极，采用多种方法研究了其电化学性质、电催化活性和分析测试性能，建立了相关物质的安培检测方法。本研究工作对丰富化学修饰电极基本理论，拓宽金属铁氰化物的研究种类，开发其在电化学传感器和电分析化学领域的实际应用，具有重要的学术意义和应用价值。全文共分三章，作者的主要贡献如下：1、采用循环伏安法，从含有HAuCl₄的酸性K₃Fe（CN）₆溶液中制备了PB修饰溶胶凝胶衍生的复合陶瓷碳电极，研究了其电化学性质和电催化活性。实验结果表明，该PB膜在电极表面以均匀的、致密的纳米团簇形式存在；PB膜中Au颗粒的存在提高了膜的导电性、加快了电极表面异相电子传递速率。该修饰电极在pH7.0 PBS溶液中具有良好的化学和电化学稳定性，对H₂O₂表现出强的电催化活性，安培法检测H₂O₂的线性范围为1.0×10⁶～5.0×10^-3mol·L^-1，检出限为5.0×10^-7mol·L^-1，电极对H₂O₂的灵敏度为28.6μA·(mmol·L^-1)^-1。2、采用柠檬酸钠还原法，从壳聚糖和HAuCl₄的混合溶液中合成了纳米金—壳聚糖分散体系，实现了葡萄糖氧化酶在上述复合物膜中的固载，并采用组合法构筑了一种电流型葡萄糖生物电化学传感器，研究了实验条件对该传感器分析测试性能的影响。实验发现：该传感器对葡萄糖具有良好的电流响应，安培法检测葡萄糖的线性范围为1.0×10^-5～2.5×10^-3mol·L^-1，检出限为5×10^-6mol·L^-1，传感器对葡萄糖的响应时间小于3s，检测葡萄糖的灵敏度为3.33μA·(mmol·L^-1)^-1，用双倒数法测得传感器的表观米氏常数为3.96×10^-3mol·L^-1。该传感器已用于血清样品中葡萄糖含量多测定。与其它已报道的传感器相比，该传感器具有灵敏度高，稳定性好、响应时间短和抗干扰能力强等特点。3、合成了铁氰化锆和铁氰化镓粉末，利用IR、XRD和SEM技术对其结构和化学组成进行了表征，通过制备Nafion/ZrHCF／CPE和Nafion／GaHCF／CPE修饰电极，研究了这两种金属铁氰化物的电化学行为和电催化性能。实验结果表明，ZrHCF和GaHCF均对H₂O₂的还原具有强的电催化活性，计时安培法测得的异相催化反应速率常数分别为0.799×10³L·mol^-1·s^-1和3.13×10³ L·mol^-1·s^-1。安培法检测H₂O₂的线性范围分别为1.0×10^-6～8.0×10⁴ mol·L^-1和5.0×10^-6～5.0×10^-4mol·L^-1，检出限分别为5×10^-7mol·L^-1和1×10^-6mol·L^-1。电极对H₂O₂的响应时间均小于5s，检测H₂O₂的灵敏度分别为25.2μA·(mmol·L^-1)^-1和27.9μA·(mmol·L^-1)^-1。用这两种修饰电极检测H₂O₂时最大的特点是大幅度的降低了其过电位，从而有效地减少了常见干扰物质的干扰，提高了分析测定的选择性。4、合成了镧系稀土元素La、Ce、Pr、Er和Tb等5种稀土金属铁氰化物，采用多种谱学方法对其化学组成和结构进行了表征，分别以溶胶凝胶衍生的复合陶瓷碳电极和碳糊电极为基础电极，采用机械固载法和组合法制备了这几种稀土金属铁氰化物修饰电极，研究了其电化学性质及电催化活性。实验表明，这些稀土元素金属铁氰化物均为颗粒较大的晶形沉淀，结构中均含有一定数目的结晶水；在循环伏安图上于0.2 V（vs．SCE）产生一对氧化还原峰，且对H₂O₂、AA和L-Cys等物质具有较强的电催化活性，计时安培法测得ErHCF、TbHCF和LaHCF修饰电极对L-Cys和AA的异相催化反应速率常数分别为2.55×10³、4.0×10³和2.71×10³L·mol^-1·s^-1；ErHCF，TbHCF和LaHCF修饰电极安培检测L-Cys和AA的线性范围分别为5.0×10^-6～5.0×10^-4、5.0×10^-7～1.0×10^-4和5.0×10^-6～2.0×10^-3mol·L^-1，检出限分别为2×10^-6、2×10^-7和8×10^-7mol·L^-1，灵敏度分别为34.2、138.8和38.8μA·（mmol·L）^-1。5、分别采用循环伏安法和两步溶胶凝胶法制备了SnHCF和CuHCF修饰的复合陶瓷碳电极，研究了其电化学性质和电催化活性。实验结果表明，这两种金属铁氰化物修饰电极分别对SO₃^2-和N₂H₄的氧化具有强的催化活性。安培法检测这两种物质的线性范围分别为8.0×10^-6～4.0×10^-4mol·L^-1和3.0×10^-6～7.5×10^-3mol·L^-1，检出限分别为3×10^-6mol·L^-1和8×10^-7mol·L^-1，灵敏度分别为14.9和118.2μA·(mmol·L^-1)^-1。响应时间均小于5s。更多还原

【Abstract】 Chemically modified electrodes （CMEs） and electrochemical sensors are one of the active research areas in modern electrochemistry and electroanalytical chemistry. Among various of modified materials used to fabricate chemically modified electrodes, polynuclear metal hexacyanoferrates have been extensive studies for the applications in electrocatalysis, electrochemical sensors, functional materials, electrochromism, molecular sieves, solid-state batteries and molecular magnetism due to their good chemical and electrochemical stability, profuse electrochemical activities. Based on the reasons mentioned above, my dissertation mainly aimed at the exploitation of new polynuclear metal hexacyanoferrates and improvement their analytical performance in electrochemical sensors fields. The electrochemical and electrocatalytic activity of PB, CuHCF, SnHCF, GaHCF, ZrHCF were investigated by fabricating their modified sol-gel derived carbon paste electrode and carbon paste electrode. On the other hand, five kinds of rare earth metal hexacyanoferrates including LaHCF, CeHCF, PrHCF, ErHCF, and TbHCF were synthesized and their spectroscopic, electrochemical characterization and electrocatalytic activity were also investigated carefully in this dissertation. Based on the above investigation results, methods of amperometric determination of H₂O₂, L-Cys, D-glucose, AA, and hydrazine were also established in my research work.The main contributions of this dissertation were summarized as follows:1. A new type of Prussian blue modified sol-gel derived carbon ceramic compositeelectrode was fabricated by using cyclic voltammetry from the single K₃Fe（CN）₆solution in the presence of HAuCl₄. The electrochemical and electrocatalytic activityof this modified electrode were investigated carefully. The experimental results showed that a compact and uniform PB nanocluster film was formed quickly on the CCE surface during the potential sweeps. This PB modified electrode had strongly electrocatalytic activity toward the reduction of H₂O₂ in pH 7.0 PBS. Under the optimum conditions, a linear dependence of the catalytic current versus H₂O₂ concentration was obtained in the range of 1.0×10^-6 to 5.0×10^-3 mol·L^-1 with a detection limit of 5.0×10^-7 mol·L^-1, and a sensitivity of 28.6μA·(mmol·L^-1)^-1.2. The nano gold-particle dispersed in chitosan solution was synthesized from the hybrid solution of HAuCl₄ and chitosan by using one step procedure. A new type of amperometric glucose biosensor base on the Nafion-CS-Gox-AuNPs hybrid film was fabricated by using sandwich configuration on the surface of PB-modified carbon ceramic composite electrode. The effects of experimental conditions on the analytical performance of this biosensor were investigated carefully. Under the optimum conditions, a linear dependence of the catalytic current versus the concentration of glucose was obtained in the range of 1.0×10^-5 to 2.5×10^-3 mol·L^-1 with a detection limit of 5.0×10^-6 mol·L^-1, and a sensitivity of S.SSμA·(mmol·L^-1)^-1. The apparent Michaelis-Menten constant K_m and the response time were 3.96×10^-3 mol·L^-1 and 5 s, respectively. The biosensor was successfully applied to determine the glucose concentration in human serum samples. Compared to other biosensors reported previously, this glucose biosensor exhibited high sensitivity, good stability, fast response time, good operational stability and anti-interferent ability.3. The gallium hexacyanoferrate and zirconium hexacyanoferrate were synthesized by co-deposition method and characterized by FTIR, XRD, and XPS techniques. Their electrochemical behavior and electrocatalytic activities were studied by fabricating Nafion/ZrHCF/CPE and Nafion/GaHCF/CPE chemically modified electrode. The experimental results showed that these two metal hexacyaoferrates exhibited strongly electrocatalytic activity toward the reduction of H₂O₂ in pH 7.0 base solution. The heterogeneous catalytic reaction rate constants determined by chronoamperometry were 0.799×10³ L·mol^-1·s^-1 for ZrHCF and 3.13×10³ L·mol^-1·s^-1 for GaHCF, respectively. Under the optimum conditions, a linear dependence of the catalytic current versus H₂O₂ concentration ware obtained in the range of 1.0×10^-6 to 8.0×10^-4 mol·L^-1 for ZrHCF and 5.0×10^-6 to 5.0×10^-4 mol·L^-1 for GaHCF with the detection limit of 5×10^-7 mol·L^-1 and 1×10^-6 mol·L^-1, respectively. The sensitivity of the modified electrodes toward H₂O₂ were 25.2μA·(mmol·L^-1)^-1 and 27.9μA·(mmol·L^-1)^-1, respectively. Compared to other metal hexacyanoferrates modified electrodes used to determine the concentration of H₂O₂, the virtue of my present work was the dramatic decrease of over-potential for the reduction of H₂O₂ in netrual medium, the operating potential of amperometric determination were 0.10 V vs. SCE, thus must be benefit for the selectivity of the determination of H₂O₂. Additionally, the simplicity for the preparation and the easy surface renew of the modified electrodes were also useful in the practical applications.4. Five kinds of lanthanide rare earth metal hexacyanoferrates of LaHCF, CeHCF, PrHCF, TbHCF and ErHCF were synthesized with the use of co-deposition method. Their spectroscopic characterizations were characterized by FTIR, XRD, XPS and SEM techniques. Furthermore, the electrochemical behavior and electrocatalytic activities of these metal hexacyanoferrates were studied carefully by fabricating of LaHCF/CPE, CeHCF/CPE, PrHCF/CPE, TbHCF/CCE and ErHCF/CCE chemically modified electrodes. The experimental results showed that all these five kind of rare earth metal hexacyanoferrates exhibited one pair of redox waves located at the low-potential region with the formal potential about 0.2 V vs. SCE on the cyclic voltammagramms. The LaHCF/CPE, ErHCF/CCE, and TbHCF/CCE had strong electrocatalytic activity toward the oxidation of AA, L-Cys, while the PrHCF/CPE had the electrocatalytic activity toward the reduction of H₂O₂. The heterogeneous catalytic reaction rate constants to AA and L-Cys determined by chronoamperometry were 2.55×10³ for LaHCF, 4.0×10³ for ErHCF, and 2.71×10³ L·mol^-1·s^-1 for TbHCF, respectively. Under the optimum conditions, a linear dependence of the catalytic current versus AA or L-Cys concentration were obtained in the range of 5.0×10^-6 to 5.0×10^-4 for ErHCF, 5.0×10^-7 to 1.0×10^-4 for TbHCF, and 5.0×10^-6 to 2.0×10^-3 mol·L^-1 for LaHCF with the detection limit of 2×10^-6, 2×10^-7, and 8×10^-7 mol·L^-1, respectively. The sensitivity of the modified electrodes were 34.2, 138.8, and 38.8μA-（mmol·L）^-1, respectively.5. Two kinds of transition metal hexacyanoferrates of CuHCF and SnHCF modified sol-gel derived carbon ceramic composite electrodes were constructed by two-step sol-gel and mechanically attachment methods, respectively. The analytical performances toward hydrazine and sodium sulfite of these two types of chemically modified electrodes were investigated carefully. Under optimum conditions, a linear dependence of the catalytic current versus the concentration of hydrazine and sodium sulfite were obtained in the range of 3.0×10^-6 to 7.5×10^-3 and 8.0×10^-6 to 4.0×10^-4 mol·L^-1, respectively. The detection limit were 8×10^-7 and 3×10^-6 mol·L^-1, respectively. The sensitivity were 14.9 and 118.2μA·(mmol·L^-1)^-1, respectively. The simplicity for the preparation and the easy surface renew of the modified electrodes were useful in the practical applications.更多还原