集成光催化预处理功能的水样重金属微分析系统研究

Environmental pollution is the most serious problem among recent social issues in the world. Photocatalytic oxidation technology presented a potential method for the treatment of water environmental contaminants, which has received significant interest and research. However, the photocatalytic oxidation being applied as sample pretreatment technology and integrated with microfluidic chip has been rarely reported. This project is to develop an on-line sample pretreatment technology which is based on liquid core waveguide optical catalytic flowing micro-reactor that is efficient for light transmission and microfluidic chip analysis that has high efficiency of microfluidic control. By uniformly coating with TiO2 film in the liquid core waveguide wall, the light can transmit efficiently over long distances within the waveguide. By coupling certain wavelength laser into the liquid core waveguide via optical fiber, coupling the waveguide into the micro-channel, and controlling the flow of sample and reagent solutions with the network structure of the chip, organic matters can be photocatalytic degradated with high efficiency in the liquid core waveguide. Then heavy metal ions in water samples is separated on-line using chip capillary electrophoresis and detected with electrochemical method..Through the study, it can not only provide a new efficient sample pretreatment method for microfluidic chip analysis, but also can establish a micro environmental water samples on-line analysis system which is composed by sample pretreatment, separation and detection. On the basis of the study, portable heavy metal analysis instrument that suitable for field monitoring is to be developed, to promote the further development of environmental analysis.

环境污染是当今社会面临的重要问题，光催化氧化技术在解决水环境污染等重大问题方面有着广泛的研究和应用，但直接作为样品预处理技术集成于微流控芯片还很少见。本项目以液芯波导技术的高光传输效率和微流控芯片的高效微流体控制为基础，研制基于液芯波导的光催化流动型微反应器和微流控芯片分析的在线样品预处理技术。通过在液芯波导管内壁均匀涂覆TiO2薄膜，使光线在波导管内长距离高效传播。通过光纤将激光耦合进液芯波导管，将波导管与微通道相耦合，利用芯片的网络结构控制样品及试剂溶液的流动，使有机物在液芯波导管中实现高效在线光催化降解。利用芯片毛细管电泳对水样中重金属离子进行在线分离和电化学检测。.通过研究，不仅能为微流控芯片分析提供一种新的高效的在线样品预处理方法，同时建立集样品预处理、分离、检测与一体的微型环境水样在线分析系统。在此基础上研究可现场监测的便携式水质重金属分析仪器，推动环境分析系统的进一步发展。

环境污染是当今社会面临的重要问题，光催化氧化技术在解决水环境污染等重大问题方面有着广泛的研究和应用，但直接作为样品预处理技术集成于微流控芯片还很少见。本项目以TiO2涂层微流控芯片的高效光催化和高效微流体控制为基础，研制光催化流动型微反应器和微流控芯片分析的在线样品预处理技术。使有机物在TiO2涂层微流控芯片中实现高效在线光催化降解。然后利用UV-VIS或电化学检测器进行有机物降解产物或重金属的在线检测。建立了集样品预处理和检测与一体的微型环境水样在线分析系统。. 在上述微型环境水样在线分析系统中实现了有机磷水样的在线光催化降解及总磷检测，总磷的检测范围为0.05-5 mg/L，检出限为0.013mg/L，与国标法的线性范围和检出限非常接近。0.1mg/L 的毒死蜱降解率达到100%，完成一次测定（包括样品消解和紫外检测）的时间约为30min。. 同时实现了EDTA-重金属水样的在线光催化及重金属Cd2+的电化学检测。Cd2+ 的检测范围为0.005~0.5mg/L，检出限为2.5μg/L。最佳条件下EDTA的降解率可达92.6%。在线检测所需的样品体积仅为0.3mL，完成一个水样分析的时间约为60min。. 在上述微型环境水样在线分析系统中还研究了有机物水样的在线光催化降解及COD检测。在优化的条件下，COD的测定范围为20-1000mg/L，与标准方法相当。. 在该微型分析系统中进行环境水样的总磷，重金属及COD测定具有操作简单，快速，试剂用量少，避免有毒试剂、珍贵试剂的使用，无二次污染等优点。有机物在微流控芯片中光催化降解反应的时间仅需20～60s，但由于受检测器死体积灵敏度的限制，整个检测过程则需要30～60min。 因此研制微型的，高灵敏的集成化检测器是今后研究的一个重点。