基于修饰电极的元素形态电化学样品引入原子光谱分析新方法研究

In this project, we proposed a new idea that the selective sample introduction of heavy metal elements by electrochemical vapor generating will be achieved through the use of the functional materials modified electrode. Realization of this working assumption can not only establish an new speciation analysis method by direct atomic spectroscopy, but also understand the vapor generation mechanism deeply on molecular levels through the research of the electron transport pathway and electrode kinetics. In this project, we will study from three aspects. Firstly, the various functional electrodes will be prepared and the effects of material type and modification method on the stability, the reproducibility and the lifetime of electrode will also be studied. Then, we will optimize the preparation routes and conditions to enhance the performance of the electrode. Secondly, the electrochemical vapor generation conditons of arsenic, tin, mercury and lead will be optimized with different modified electrodes. We will obtain the best detection conditions, linear range and detection limit of each elements based on a large number of experimental data. At the same time, the possible interference will be studied and eliminated. The reasons of the different electrochemical vapor generating behaviors between heavy metal elements will be explored under the control of functional materials and different electrolytic conditions. Lastly, the relationship between the electrolyte systems and the component of products will be analyzed by various analytic technologies to deduce the reaction process of the electrochemical vapor generation of heavy metal elements. In situ spectroelectrochemistry methods will be used to study the generation mechanism of heavy metals. The kinetic and thermodynamic data of reaction will also be studied. These works will provide new ideas and methods for the development of atomic spectroscopy as well as the detection of heavy metal elements.

通过特定基团促使电极功能化，从而实现重金属元素形态的电化学蒸气发生选择性样品引入，不仅有助于建立元素形态原子光谱直接分析新方法，同时对于电子传递途径及电极反应动力学的研究，有望在分子水平上揭示蒸气发生机制与动力学因素。本项目将系统研究功能材料种类、修饰方法等因素对电极使用寿命、稳定性和重现性的影响，优化制备路线及条件，提升电极使用性能。结合不同功能材料，对砷、锡、汞、铅等重金属元素形态的电化学蒸气发生条件进行优化，消除可能的干扰，确定各元素形态的最佳检测条件、定量范围及检出限。探讨在功能材料及电化学参数调控下，实现重金属元素形态选择性蒸气发生的可行性。利用各种表征及检测手段，研究电解体系与产物之间的关系。根据光谱电化学、热力学及动力学数据，研究重金属元素的电还原历程，揭示重金属元素蒸气态物质的生成机制，从而推动原子光谱技术的发展并为重金属元素形态分析提供新的思路与手段。

对于环境及生物样品中重金属元素含量、尤其是其存在形态的直接超灵敏分析，是当前原子光谱领域研究的热点和难点问题之一。本项目从选择性样品引入的角度出发，将电化学蒸气发生技术与修饰电极有机结合，通过电极材料及参数控制，以实现元素形态的差异化反应；同时探讨了在功能材料及新型增敏体系作用下的重金属元素富集、（光）催化化学还原可行性，并据此建元素及其形态的原子光谱直接超灵敏分析技术，具体包括：以共价键合和电镀法制备了半胱氨酸、谷胱甘肽等巯基化合物和金属粒子修饰电极，系统研究了砷、硒、汞等在内的多种重元素不同形态化合物在上述电极上的电化学蒸气发生行为差异，利用电解参数和修饰物的调控，实现了砷、汞、硒等元素不同形态的选择性蒸气发生，并据此建立了相关元素形态的原子光谱直接分析方法；通过碳糊法成功构建了半胱氨酸修饰和谷胱甘肽碳糊电极，解决了共价键和法所制备的电极寿命短的缺陷，从而为电化学蒸气发生技术的商品化应用创造了可能；利用磁性吸附材料对痕量重金属元素进行高效富集，对超声波的协同作用进行了详细研究，进而构建了一系列基于超声波的高效样品前处理、重金属富集等新方法；研究了半胱氨酸-过渡金属离子体系在镉的化学蒸气发生过程中的催化增敏作用，并对铬在复合材料上的高效光催化还原进行了探讨；此外还对镉、砷、硒等元素（电）化学反应机理进行了研究，提出了半胱氨酸-Fe2+协同催化镉的化学蒸气反应以及砷、硒等元素与修饰电极中巯基结合，进而影响电子传递途径的反应机制。.作为项目研究成果，共计发表标注本项目资助SCI收录论文7篇，其中3篇发表在IF>4.0的国际主流分析化学期刊上。