食品重金属纳米电化学传感及现场检测新方法研究

To develop novel nanoelectrochemical sensors for heavy metal ions and to fulfill in-situ, rapid and trace detection, nanostructured sensing composite films with raid response, high sensitivity and good selectivity were constructed based on the combination of strong cationic-exchange ability of Nafion with the highly-sensitive sensing properties of graphene or mesoporous carbon. The electrochemical sensing properties of nanocomposited films, such as response areas, electron transfer way and surface mass transport behavior, were examined in detail. The remarkable signal enhancement effect, facilitating electron transfer and selective accumulation effect were obtained for the nanocomposited interface. Based on this, electrochemical enhancement theory was developed for the nanocomposited interference. After that, the sensing and signal transfer mechanisms of heavy metal ions on the nanocomposited sensing films were investigated to deeply discover the electrochemical scientific questions for the remarkable enhancement of response signal, electron transfer rate and selectivity. As a result, novel theory and method for highly sensitive and selective electrochemical detection of heavy metal ions were successfully developed. Subsequently, new nanoelectrochemical sensors for in-situ and rapid detection of heavy metal ions were constructed, which was used in the food samples. . From this work, we can acquire new thinking about sensing theory and preparation of nanocomposited interface. The obtained sensing theory, sensing mechanism and preparation method are helpful to develop highly-sensitive and novel electrochemical sensing system. Meanwhile, this work will provide new method and new technology for the rapid and in-site food safety analysis. Therefore, it is quite important to construct defense line for food security.

为研发新型重金属纳米电化学传感器，实现痕量现场快速检测，课题将石墨烯、介孔碳的高灵敏传感特性与Nafion强的阳离子交换能力复合，构建响应速度快、灵敏度高、选择性好的新型重金属纳米复合敏感膜。系统研究纳米复合膜的响应面积、电子传递途径、表面传质行为等电化学传感特性，获得纳米复合界面显著的信号增强效应、加速界面电子转移效应和选择富集效应，建立纳米复合界面电化学增强理论。研究重金属离子的纳米敏感机理和信号转换机制，探讨纳米复合膜显著提高重金属离子响应信号、电子交换速率和选择性的电化学科学问题，建立高灵敏度、高选择性的电化学检测新理论和新方法，构建适合现场快速分析的新型重金属纳米电化学传感器，用于食品样品分析。 课题所获得的纳米复合界面传感理论和制备原理有利于构筑更广泛的高灵敏纳米电化学传感新体系。同时，课题为食品安全的现场快速检测提供新方法和新技术，对牢筑食品安全防线具有重要现实意义。

围绕重金属离子的高灵敏电化学传感检测新方法开展了系统的研究，分别以介孔二氧化硅、NMP剥离石墨烯、还原石墨烯(rGO)-纳米ZnO复合物（ZnO@rGO）等为敏感材料，构建了多种新型的重金属离子电化学传感界面，研究了显著提高重金属离子响应信号、电子交换速率和选择性的电化学科学问题，获得了界面增敏机制，建立了痕量重金属离子的电化学检测新方法，用于食品和环境样品分析，测定结果与大型仪器一致；发表了8篇SCI论文，获批发明专利1项，圆满完成了各项研究任务。主要成果如下：.基于SBA-16构建的铅镉电化学传感平台。通过软模板法合成出一种介孔二氧化硅SBA-16，研究发现SBA-16对铅镉离子有很高的富集效率，能显著提高二者的响应信号，并且在I-存在时增敏效应进一步提升；基于此建立了一种同时测定铅镉离子的电化学新方法，检出限在nM水平；用于环境水样分析，结果与AAS一致。.基于NMP剥离石墨烯构建的铅镉电化学传感器。以NMP为剥离溶剂，通过一步超声制备出石墨烯纳米片；发现NMP剥离石墨烯具备较大的电化学传感表面和较强的电子交换能力；此外对铅镉离子的信号增强效应显著高于广泛使用的还原石墨烯（rGO），探讨了增敏机制，研制出一种同时测定铅镉离子的电化学传感器，检出限在1 ppb水平。将传感器用于水样分析，结果与ICP-AES一致。.基于NMP剥离石墨烯/Bi膜协同增敏的铅镉电化学传感平台。研究发现NMP剥离石墨烯和Bi3+对铅镉离子响应信号有明显的协同增敏效应，基于此构建了一种更高灵敏度的铅镉电化学传感平台，检出限在0.1 ppb水平；用于紫菜样品分析，结果与ICP-MS一致。.基于ZnO@rGO信号增强的铅离子电化学检测新方法。利用Zn粉原位还原石墨烯氧化物（GO），制备出rGO与纳米ZnO的复合物（ZnO@rGO）, 研究发现ZnO@rGO对铅离子的增敏效应显著高于GO，建立了一种快速测定痕量铅离子的电化学新方法，检出限味0.02 ppb；用于牛奶分析，结果与ICP-MS一致。