Anal Chem. 2011 Jul 15;83(14):5476-9. doi: 10.1021/ac201228v. Epub 2011 Jun 22.
This report introduces a new analytical concept utilizing the mass transfer resistance of a liquid-liquid interface to concentrate and separate DNA samples. DNA molecules can be electrophoretically accumulated at a liquid-liquid interface of an aqueous two-phase system (ATPS) of poly(ethylene glycol) (PEG) and dextran, two polymers that form two immiscible phases in aqueous electrolyte solutions. The detachment of DNA from the interface into the other phase can be triggered by increasing the applied electric field. We experimentally study the size dependence of the detachment process for a broad spectrum of DNA fragments. In a regime where the coiling of the chains does not play a significant role, the process shows a linear dependence on the diffusion coefficient, with shorter DNA chains detaching at lower electric field strengths than larger ones. The concept may enable novel separation protocols for preparative and analytical purposes.
本报告介绍了一种新的分析概念，利用液-液界面的传质阻力来浓缩和分离 DNA 样品。DNA 分子可以在聚乙二醇（PEG）和葡聚糖的水相两相间（ATPS）的液-液界面处通过电泳累积，这两种聚合物在电解质水溶液中形成两个不混溶的相。通过增加施加的电场，可以触发 DNA 从界面进入另一个相的分离。我们实验研究了广泛的 DNA 片段的分离过程对尺寸的依赖性。在链的缠绕不发挥重要作用的范围内，该过程与扩散系数呈线性关系，较短的 DNA 链在较低的电场强度下分离，而较长的 DNA 链则在较高的电场强度下分离。该概念可能为制备和分析目的开辟新的分离方案。
