Xia Ling, Dutta Debashis
Department of Applied Chemistry, Sun Yat-Sun University, Guangzhou, People's Republic of China.
Department of Chemistry, University of Wyoming, Laramie, WY, USA.
Methods Mol Biol. 2019;1906:239-249. doi: 10.1007/978-1-4939-8964-5_16.
It is well known that the resolving power of capillary zone electrophoretic separations may be improved with an increase in the applied electric field strength and separation time. While large electric fields may be realized in short analysis channels commonly employed in microfluidic systems, this experimental design is not suitable for achieving long separation times. In this chapter, we describe the use of a steady and/or a periodic pressure-driven backflow to increase the separation time in short microchannels thereby enabling the analysis of closely related species on microchip devices. The reported backflow was realized in our assays using an on-chip pressure-generation capability that relied on the partial blockage of electroosmotic flow around a junction of two glass channel segments having different depths. Although the noted strategy led to additional band broadening in the system, the resolving power of our device was observed to substantially improve upon introduction of the reported steady/periodic pressure-driven backflow for analysis channels shallower than 5 μm.
众所周知，毛细管区带电泳分离的分辨率可随着施加电场强度和分离时间的增加而提高。虽然在微流体系统中常用的短分析通道中可以实现大电场，但这种实验设计不适用于实现长分离时间。在本章中，我们描述了使用稳定和/或周期性压力驱动的回流来增加短微通道中的分离时间，从而能够在微芯片装置上分析密切相关的物种。在我们的测定中，所报道的回流是利用芯片上的压力产生能力实现的，该能力依赖于在两个具有不同深度的玻璃通道段的连接处周围电渗流的部分阻塞。尽管上述策略导致系统中出现额外的谱带展宽，但当为深度小于5μm的分析通道引入所报道的稳定/周期性压力驱动回流时，我们观察到装置的分辨率有显著提高。
