Bekri Samya, Leclercq Laurent, Cottet Hervé
Institut des Biomolécules Max Mousseron (IBMM, UMR 5247, CNRS, Université de Montpellier, ENSCM), Place Eugène Bataillon, CC 1706, 34095 Montpellier Cedex 5, France.
Institut des Biomolécules Max Mousseron (IBMM, UMR 5247, CNRS, Université de Montpellier, ENSCM), Place Eugène Bataillon, CC 1706, 34095 Montpellier Cedex 5, France.
J Chromatogr A. 2016 Feb 5;1432:145-51. doi: 10.1016/j.chroma.2015.12.060. Epub 2015 Dec 24.
The ionic strength is one of the key parameters for optimizing CE separations. However, only a few data are available in the literature about the ionic strength effect on the separation of proteins. The effect of ionic strength on separation performances is rather complex since many different parameters are involved: such as the protein effective mobility, the electroosmotic mobility, the separation efficiency via the electromigration dispersion, as well as the viscosity and temperature of the background electrolyte. In the present work, the influence of ionic strength on the electrophoretic separation of five model proteins has been investigated in acidic conditions, on successive multi-ionic layers coated capillary, in counter-electroosmotic mode with anodic electroosmotic flow. The decrease in effective and electroosmotic mobilities with increasing ionic strength were compared using the slope-plot approach, which is very helpful for understanding the observed changes in apparent selectivity and resolution. The relative decrease of the protein effective mobility was about 30-40% of the mobility determined at 5mM ionic strength per ionic strength decade. It was found that relatively low ionic strength (∼5-10mM) was preferable to optimize the overall separation of the five model proteins.
离子强度是优化毛细管电泳分离的关键参数之一。然而，关于离子强度对蛋白质分离影响的文献数据较少。离子强度对分离性能的影响相当复杂，因为涉及许多不同参数，如蛋白质有效迁移率、电渗迁移率、通过电迁移扩散的分离效率以及背景电解质的粘度和温度。在本工作中，研究了在酸性条件下，在连续多层离子涂层毛细管中，以阳极电渗流的反向电渗模式，离子强度对五种模型蛋白质电泳分离的影响。使用斜率图方法比较了有效迁移率和电渗迁移率随离子强度增加的降低情况，这对于理解表观选择性和分辨率的观察变化非常有帮助。蛋白质有效迁移率的相对降低约为每离子强度十年在5mM离子强度下测定迁移率的30 - 40%。发现相对较低的离子强度（约5 - 10mM）更有利于优化五种模型蛋白质的整体分离。
