Goyal Sachit, Desai Amit V, Lewis Robert W, Ranganathan David R, Li Hairong, Zeng Dexing, Reichert David E, Kenis Paul J A
Department of Chemical & Biomolecular Engineering, University of Illinois, Urbana-Champaign, Urbana, IL 61801, USA.
Department of Chemical & Biomolecular Engineering, University of Illinois, Urbana-Champaign, Urbana, IL 61801, USA ; Chemical and Biological Engineering, The University of Sheffield, Sheffield, United Kingdom.
Sens Actuators B Chem. 2014 Jan 1;190:634-644. doi: 10.1016/j.snb.2013.09.065.
Microfluidic platforms provide several advantages for liquid-liquid extraction (LLE) processes over conventional methods, for example with respect to lower consumption of solvents and enhanced extraction efficiencies due to the inherent shorter diffusional distances. Here, we report the development of polymer-based parallel-flow microfluidic platforms for LLE. To date, parallel-flow microfluidic platforms have predominantly been made out of silicon or glass due to their compatibility with most organic solvents used for LLE. Fabrication of silicon and glass-based LLE platforms typically requires extensive use of photolithography, plasma or laser-based etching, high temperature (anodic) bonding, and/or wet etching with KOH or HF solutions. In contrast, polymeric microfluidic platforms can be fabricated using less involved processes, typically photolithography in combination with replica molding, hot embossing, and/or bonding at much lower temperatures. Here we report the fabrication and testing of microfluidic LLE platforms comprised of thiolene or a perfluoropolyether-based material, SIFEL, where the choice of materials was mainly guided by the need for solvent compatibility and fabrication amenability. Suitable designs for polymer-based LLE platforms that maximize extraction efficiencies within the constraints of the fabrication methods and feasible operational conditions were obtained using analytical modeling. To optimize the performance of the polymer-based LLE platforms, we systematically studied the effect of surface functionalization and of microstructures on the stability of the liquid-liquid interface and on the ability to separate the phases. As demonstrative examples, we report (i) a thiolene-based platform to determine the lipophilicity of caffeine, and (ii) a SIFEL-based platform to extract radioactive copper from an acidic aqueous solution.
与传统方法相比，微流控平台在液-液萃取（LLE）过程中具有多个优势，例如溶剂消耗更低，且由于固有的较短扩散距离而提高了萃取效率。在此，我们报告了用于LLE的基于聚合物的平行流微流控平台的开发情况。到目前为止，由于平行流微流控平台与用于LLE的大多数有机溶剂具有兼容性，因此主要由硅或玻璃制成。基于硅和玻璃的LLE平台的制造通常需要大量使用光刻、基于等离子体或激光的蚀刻、高温（阳极）键合和/或用KOH或HF溶液进行湿法蚀刻。相比之下，聚合物微流控平台可以使用不太复杂的工艺制造，通常是光刻结合复制成型、热压印和/或在低得多的温度下键合。在此我们报告了由硫醇烯或基于全氟聚醚的材料SIFEL组成的微流控LLE平台的制造和测试，其中材料的选择主要受溶剂兼容性和制造便利性需求的指导。使用分析模型获得了基于聚合物的LLE平台的合适设计，这些设计在制造方法和可行操作条件的限制内使萃取效率最大化。为了优化基于聚合物的LLE平台的性能，我们系统地研究了表面功能化和微观结构对液-液界面稳定性以及相分离能力的影响。作为示例，我们报告了（i）一个基于硫醇烯的平台用于测定咖啡因的亲脂性，以及（ii）一个基于SIFEL的平台用于从酸性水溶液中萃取放射性铜。
