Core-based hyperbranched polyethyleneimine coating in capillary electrophoresis

In capillary electrophoresis (CE), chemical and dynamic modification of a fusedsilica surface can be used to control the electroosmotic flow (EOF), to minimize the interaction of analytes with the capillary surface and to modify the selectivity. Polyvalent, core-based hyperbranched polyethyleneimine (CHPEI) polymer was utilized as either a static or dynamic coating in this study. A CHPEI-coated capillary was simply constructed in a rinsing fashion or by adding CHPEI in a running buffer. Two generations of CHPEI, CHPEI5 and CHPEI25, were investigated with the concentration ranges from 5-20% (w/v) for the static-coating method and 0.6-1.25% (w/v) for the dynamic-coating method.