Abstract
Summary: This work reports the separation of polyelectrolytes according to their charge density and their molecular mass by two‐dimensional capillary electrophoresis (2D‐CE). The two dimensions of the separation are performed in the same capillary using a heart‐cutting approach. The first dimension of the separation is performed in free‐solution CE (i.e. in the absence of sieving matrix) and allows separating the polyelectrolytes according to their charge density. A selected fraction stemming from the first dimension is next submitted to a second separation medium that is introduced in the capillary by electro‐osmotic flow. The second dimension of the separation is performed in the presence of an entangled polymer solution and allows the size‐based separation of the polyelectrolytes. The interest of heart‐cutting 2D‐CE in comparison with one‐dimensional separations is clearly demonstrated using a model mixture containing ten synthetic polyelectrolytes. Good repeatability on migration times (RSD from 0.12% to 0.33%, calculated on 5 successive runs) and relative peak areas (RSD from 0.74% to 3.6%) was obtained using this new methodology.
Two‐dimensional capillary electrophoresis separation of ten polyelectrolytes.
magnified imageTwo‐dimensional capillary electrophoresis separation of ten polyelectrolytes.