Department of Analytical Chemistry, University of Barcelona, Diagonal 647, 08028 Barcelona, Spain.
Anal Bioanal Chem. 2010 Feb;396(4):1571-9. doi: 10.1007/s00216-009-3344-1. Epub 2009 Dec 15.
Modelling electrophoretic mobility as a function of pH can be simultaneously used for determination of ionization constants and for rapid selection of the optimum pH for separation of mixtures of the modelled compounds. In this work, equations describing the effect of pH on electrophoretic behaviour were used to investigate migration of a series of polyprotic amphoteric peptide hormones between pH 2 and 12 in polybrene-coated capillaries. Polybrene (hexadimethrin bromide) is a polymer composed of quaternary amines that is strongly adsorbed by the fused-silica inner surface, preventing undesired interactions between the peptides and the inner capillary wall. In polybrene-coated capillaries the separation voltage must be reversed, because of the anodic electroosmotic flow promoted by the polycationic polymer attached to the inner capillary wall. The possibility of using polybrene-coated capillaries for determination of accurate ionization constants has been evaluated and the optimum pH for separation of a mixture of the peptide hormones studied has been selected. Advantages and disadvantages of using bare fused-silica and polybrene-coated capillaries for these purposes are discussed.
可以通过模拟电泳迁移率作为 pH 的函数，同时确定电离常数并快速选择最佳 pH 值，以分离所模拟化合物的混合物。在这项工作中，使用描述 pH 对电泳行为影响的方程来研究一系列多质子两性肽激素在聚亚胺涂层毛细管中 pH 2 至 12 之间的迁移。聚亚胺（六亚甲基二溴化铵）是一种由季铵盐组成的聚合物，强烈吸附在熔融二氧化硅内表面上，防止肽与内毛细管壁之间发生不需要的相互作用。由于与内毛细管壁相连的聚阳离子聚合物促进了阳极电渗流，因此必须反转聚亚胺涂层毛细管中的分离电压。已经评估了使用聚亚胺涂层毛细管来确定准确电离常数的可能性，并选择了分离该肽激素混合物的最佳 pH 值。讨论了为这些目的使用裸熔融二氧化硅和聚亚胺涂层毛细管的优缺点。
