新型金属有机骨架固相萃取材料的制备及其在金属离子快速分离分析中的应用研究

Metal-organic frameworks (MOFs) are a new type of solid material, which have received great attention due to their designable structures and intriguing potential applications in various fields. Herein, we report the synthesis,characterization and utilization of MOFs for renewable solid-phase extraction of metal ions in a sequential injection lab-on-valve platform. These results will be introduced from the following issues: According to the principle of molecular engineering, new kinds of MOFs will be synthesized by selecting different organic ligands and certain geometric metal ions; Synthetic conditions for MOFs, such as solvent, pH and temperature etc. of the final products at hydrothermal conditions, will be researched. Structure and thermal stabilization of the MOFs will be characterized by various of analysis methods including infrared spectra,element analysis, X-ray single crystal diffraction and thermal gravity analysis; Bead substrates will be functionalized with MOFs material and the key experimental variables relevant to the modification procedures will be studied and optimized; A sequential injection system incorporated a lab-on-valve unit and a detector will be employed for sample/reagent delivery and target analyte determination. The extraction and elution procedures for metal ions will be proposed by incorporating a renewable microcolumn in the lab-on-valve system. The adsorption property and the adsorption mechanism of the MOFs toward metal ions will be investigated in detail in order to explore the structures and their adsorption properties for metal ions. This work will pave the way for the development of a new class of solid-phase extraction materials for the separation and preconcentration of metal ions.

本项目提出以金属有机骨架作为新型的固相萃取材料，并基于顺序注射阀上实验室建立金属离子的可更新表面固相萃取分离及定量方法。主要研究内容有: 依据晶体工程学原理，从金属有机骨架晶体材料的功能出发，合成对金属具有富集作用的金属有机骨架材料，考察不同反应条件对金属有机骨架材料结构和配体的配位模式的影响，对其进行单晶结构解析，并研究配体和骨架结构赋予这些材料在金属富集方面的性能；尝试以具有优良阀内可控性的微珠作为载体,研究金属有机骨架材料在载体表面的修饰行为和条件；设计加工适当的阀上实验室检测单元，以顺序注射为溶液引入装置，结合可更新表面固相萃取技术实现金属有机骨架材料在阀内的流体控制，研究金属离子在富集和洗脱过程中的影响因素，阐述相关的萃取机理。该课题的完成将为金属离子的分析开辟一条新的途径。

金属有机骨架是近年来材料及相关领域的一个研究热点，但应用研究领域仍有待进一步挖掘和拓展。基于此，本项目合成了一系列金属有机骨架复合材料，例如Fe3O4/Cu3(BTC)2-H2Dz，Fe3O4/Cu3(BTC)2-SH和Cu3(BTC)2-SO3H，将其作为固相萃取吸附剂用于金属离子的分离和富集，对金属离子的吸附等温线、吸附动力学和热力学性质以及干扰情况进行了研究，并结合原子吸收光谱仪实现了金属离子的痕量测定。制备了碳糊、氨基和多壁碳纳米管修饰的金属有机骨架复合材料用于提高金属有机骨架的导电性和选择性，将其作为电极修饰材料用于金属离子的检测，并进一步研究了各种材料的协同效应。将金属有机骨架材料用于顺序注射阀上实验室内部，进行在线样品的引入和输送，实现了金属离子分离富集和检测的集成化，通过分析复杂环境和生物样品中金属离子的含量验证了方法的准确性和可行性。通过本项目的研究同时发现，基于金属有机骨架复合材料（Cu3(BTC)2/β-CD，Nafion/C/Al-MIL-53-(OH)2和 Cu3(BTC)2/GO）的电化学传感器对有机小分子也展现了很好的选择性和检测灵敏度，本项目也将为有机小分子的检测开辟一条新的途径。