新型化学修饰电极的构建及其在COD检测中的应用和碳量子点的制备及其性质研究
发布时间：2018-11-15 19:58
【摘要】：化学需氧量(COD)是评价水体污染程度的重要综合指标之一,指一定条件下,水体中的还原性物质被强氧化剂氧化消耗的氧化剂所对应的氧的浓度。随着我国工农业的快速发展和城市化进程的日益加剧,环境污染问题日益严重。目前,我国测定COD的标准方法主要是重铬酸钾法,该方法准确度高、重现性好,应用最为广泛。但是重铬酸盐法操作过程耗时长,测定成本高,二次污染较严重；受回流装置的限制,难以同时分析大批量样品。为了改进以上缺点,缩短分析时间,实现COD的在线监测,研发快速、灵敏、简便的环境监测新方法和新技术显得十分重要。运用纳米材料,如纳米碳材料、纳米金属和金属氧化物材料、有机聚合膜及其相关的复合材料作为修饰电极是当前化学修饰电极发展的新方向,对于提高分析方法的灵敏度和选择性具有重要意义。基于此,本文构建了两种新型的化学修饰电极,可以灵敏、快速、简便地电化学检测COD并成功应用于地表水COD的检测分析,具体的内容与结果如下： 1、以Co(NO3)2为前驱体,利用恒电位氧化技术在玻碳电极表面原位制备出纳米钴氧化物敏感膜。直接以湖水水样为研究对象,考察了沉积电位、沉积介质、沉积时间以及Co2+的浓度对COD响应信号的影响规律并成功调控了纳米钴氧化物敏感膜的形貌,结果表明纳米钴氧化物敏感膜能显著提高COD的电化学响应信号,建立了一种简便、灵敏、快速测定COD的电化学方法,在COD值为1.7mgL-1到170mg L-1的范围内,其响应信号与COD值呈现良好的线性关系。该方法的检出限为1.1mg L-1。为验证钻氧化物敏感膜的实际应用,将新方法应用于不同湖泊水水样的COD值测定,测定结果与重铬酸钾法测定结果有很好的一致性。 2、以Co(NO3)2和CuCl2为前驱体通过电化学沉积法在金电极表面原位制备出了微纳米铜钻合金敏感膜。在此基础上,以葡萄糖为电化学测定COD的标准物,系统考察了改变Cu2+、Co2+离子浓度比、沉积电流、沉积介质以及沉积时间对响应信号的影响规律并成功调控了微纳米Cu-Co敏感膜的形貌。结果表明,所制备的微纳米Cu-Co敏感膜能显著提高COD的电化学响应信号,并利用安培检测法实现了COD的快速电化学测定,其线性范围为1.92mg L1-768mgL-1,基于3倍信噪比的检出限为0.609mg L-。将此方法用于实际水样COD的测定,重复性高,并与国标方法进行了对比,测定结果与国标方法结果相吻合。 3、荧光碳量子点(Carbon dots)作为一种新型的碳纳米材料,在近年来引起了广泛关注。碳量子点的粒径一般小于10nm。碳量子点相对于传统荧光染料和半导体量子点往往表现出良好的荧光强度、较强的稳定性、可调控的发射波长、较高的溶解性、很好的生物相容性等特点,因此越来越被广泛应用于细胞成像,药物传输、小分子传感检测、生命科学等。本文第四章以葡萄糖和叶酸为前驱体通过热解法合成了高量子产率的磷掺杂碳量子点(量子产率为21.82%)。该碳量子点可被Fe3+选择性淬灭,基于此,建立了检测Fe3+的荧光体系,研究了磷酸盐溶液浓度、磷酸盐溶液pH、热解时间及热解温度对碳量子点荧光强度及Fe3+检测能力的影响。将此新方法应用于人血清Fe3+的测定,测定结果与火焰原子吸收光谱法测定结果相一致性。最后将制备的荧光碳量子点应用于细胞成像,结果显示高分化的大鼠肾上腺嗜铬细胞瘤细胞(PC12细胞)在蓝光下受激发发出明亮、均匀的蓝色荧光。
[Abstract]:The chemical oxygen demand (COD) is one of the important comprehensive indexes to evaluate the degree of water pollution. With the rapid development of industry and agriculture in China and the increasing process of urbanization, the problem of environmental pollution is becoming more and more serious. At present, the standard method for the determination of COD in China is mainly the potassium dichromate method. The method has the advantages of high accuracy, good reproducibility and wide application. but the process of the dichromate method has the advantages of long operation time, high measurement cost and serious secondary pollution, and is difficult to analyze large batch samples at the same time by the restriction of the reflux device. In order to improve the above disadvantages, it is very important to shorten the analysis time, realize the on-line monitoring of COD, and develop a new method and new technology for rapid, sensitive and simple environment monitoring. The use of nano-materials, such as nano-carbon materials, nano-metal and metal oxide materials, organic polymer films and related composite materials as modified electrodes, is a new direction for the development of the current chemical modification electrode, and is of great significance for improving the sensitivity and selectivity of the analytical method. On the basis of this, two new chemical modification electrodes are constructed, which can be sensitive, rapid, and can be used for the detection and analysis of COD in surface water. The specific contents and results are as follows: 1. Prior to Co (NO3) 2 in situ preparation of nano-cobalt oxide in that surface of a glass-carbon electrode by using a constant-potential oxidation technique The effect of the deposition potential, the deposition medium, the deposition time and the concentration of Co2 + on the response signal of COD was studied. The influence of the concentration of Co2 + on the response signal of COD was studied. The results show that the nano-cobalt oxide-sensitive film can obviously improve the electrochemical response signal of COD, and a simple, sensitive and rapid electrochemical method for measuring COD is established. The response signal and the COD value show a good linearity in the range of COD value of 1. 7mgL-1 to 170mg L-1. The detection limit of the method is 1. 1mg L.-1. In order to verify the practical application of the oxide-sensitive membrane, the new method is applied to the determination of COD in water samples of different lakes. The results of the determination and the potassium dichromate method are very good. The micro-nano-copper drill was prepared in situ on the surface of the gold electrode by electrochemical deposition using Co (NO3) 2 and CuCl2 as the precursor. The influence of Cu 2 +, Co2 + ion concentration ratio, deposition current, deposition medium and deposition time on the response signal was investigated by using glucose as the standard for electrochemical measurement of COD, and the micro-nano Cu-Co-sensitive was successfully controlled. The results show that the prepared micro-nano Cu-Co sensitive film can obviously improve the electrochemical response signal of COD, and the rapid electrochemical measurement of COD is realized by the Ampere detection method. The linear range of the micro-nano Cu-Co-sensitive film is 1. 922mg L1-768mgL-1, and the detection limit based on the 3-times signal-to-noise ratio is 0.60. The method is used for the determination of COD in the real water sample, the repeatability is high, and compared with the national standard method, the determination result and the national standard method The result is in agreement with. 3. Carbon Dots is a new type of carbon nano-material, in recent years to give rise to a wide range of concerns. The carbon quantum dots are generally less than 10nm. The carbon quantum dots tend to exhibit good fluorescence intensity, strong stability, controllable emission wavelength, high solubility, good biocompatibility and the like with respect to the conventional fluorescent dye and the semiconductor quantum dot, cellular imaging, drug delivery, small molecular sensing, In the fourth chapter, a high quantum yield of phosphorus-doped carbon quantum dots (quantum yield) is synthesized by thermal decomposition with glucose and folic acid as the precursor. The carbon quantum dot can be selectively quenched by Fe3 +, and based on this, a fluorescence system for detecting the Fe3 + is established, the concentration of phosphate solution, the pH of the phosphate solution, the pyrolysis time and the pyrolysis temperature on the fluorescence intensity of the carbon quantum dot and the Fe3 + are studied. and the effect of the new method on the determination of the human serum Fe3 +, the determination result and the flame atomic absorption spectrum method, The results showed that the high-differentiated rat adrenal pheochromocytoma cells (PC12 cells) were stimulated by excitation under the blue light.
【学位授予单位】：华中科技大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：R123
[Abstract]:The chemical oxygen demand (COD) is one of the important comprehensive indexes to evaluate the degree of water pollution. With the rapid development of industry and agriculture in China and the increasing process of urbanization, the problem of environmental pollution is becoming more and more serious. At present, the standard method for the determination of COD in China is mainly the potassium dichromate method. The method has the advantages of high accuracy, good reproducibility and wide application. but the process of the dichromate method has the advantages of long operation time, high measurement cost and serious secondary pollution, and is difficult to analyze large batch samples at the same time by the restriction of the reflux device. In order to improve the above disadvantages, it is very important to shorten the analysis time, realize the on-line monitoring of COD, and develop a new method and new technology for rapid, sensitive and simple environment monitoring. The use of nano-materials, such as nano-carbon materials, nano-metal and metal oxide materials, organic polymer films and related composite materials as modified electrodes, is a new direction for the development of the current chemical modification electrode, and is of great significance for improving the sensitivity and selectivity of the analytical method. On the basis of this, two new chemical modification electrodes are constructed, which can be sensitive, rapid, and can be used for the detection and analysis of COD in surface water. The specific contents and results are as follows: 1. Prior to Co (NO3) 2 in situ preparation of nano-cobalt oxide in that surface of a glass-carbon electrode by using a constant-potential oxidation technique The effect of the deposition potential, the deposition medium, the deposition time and the concentration of Co2 + on the response signal of COD was studied. The influence of the concentration of Co2 + on the response signal of COD was studied. The results show that the nano-cobalt oxide-sensitive film can obviously improve the electrochemical response signal of COD, and a simple, sensitive and rapid electrochemical method for measuring COD is established. The response signal and the COD value show a good linearity in the range of COD value of 1. 7mgL-1 to 170mg L-1. The detection limit of the method is 1. 1mg L.-1. In order to verify the practical application of the oxide-sensitive membrane, the new method is applied to the determination of COD in water samples of different lakes. The results of the determination and the potassium dichromate method are very good. The micro-nano-copper drill was prepared in situ on the surface of the gold electrode by electrochemical deposition using Co (NO3) 2 and CuCl2 as the precursor. The influence of Cu 2 +, Co2 + ion concentration ratio, deposition current, deposition medium and deposition time on the response signal was investigated by using glucose as the standard for electrochemical measurement of COD, and the micro-nano Cu-Co-sensitive was successfully controlled. The results show that the prepared micro-nano Cu-Co sensitive film can obviously improve the electrochemical response signal of COD, and the rapid electrochemical measurement of COD is realized by the Ampere detection method. The linear range of the micro-nano Cu-Co-sensitive film is 1. 922mg L1-768mgL-1, and the detection limit based on the 3-times signal-to-noise ratio is 0.60. The method is used for the determination of COD in the real water sample, the repeatability is high, and compared with the national standard method, the determination result and the national standard method The result is in agreement with. 3. Carbon Dots is a new type of carbon nano-material, in recent years to give rise to a wide range of concerns. The carbon quantum dots are generally less than 10nm. The carbon quantum dots tend to exhibit good fluorescence intensity, strong stability, controllable emission wavelength, high solubility, good biocompatibility and the like with respect to the conventional fluorescent dye and the semiconductor quantum dot, cellular imaging, drug delivery, small molecular sensing, In the fourth chapter, a high quantum yield of phosphorus-doped carbon quantum dots (quantum yield) is synthesized by thermal decomposition with glucose and folic acid as the precursor. The carbon quantum dot can be selectively quenched by Fe3 +, and based on this, a fluorescence system for detecting the Fe3 + is established, the concentration of phosphate solution, the pH of the phosphate solution, the pyrolysis time and the pyrolysis temperature on the fluorescence intensity of the carbon quantum dot and the Fe3 + are studied. and the effect of the new method on the determination of the human serum Fe3 +, the determination result and the flame atomic absorption spectrum method, The results showed that the high-differentiated rat adrenal pheochromocytoma cells (PC12 cells) were stimulated by excitation under the blue light.
【学位授予单位】：华中科技大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：R123
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