ABSTRACT
The adsorption of neutral polymers onto the inner walls of fusedsilica capillaries is a simple and fast method for masking the silanol groups of the surface. With hydrophilic coatings, highly efficient separations of proteins are achieved with good reproducibilities, whereas hydrophobic polyethylene-coated capillaries lead to poor peak shapes [18]. Thus, neutral hydrophilic coatings are preferred for the analysis of proteins by CE. They reduce both protein adsorption and the EOF. Still, the EOF is not completely eliminated and variations are often observed with pH, due to the residual silanols of the surface. However, it is sometimes interesting to have a moderate EOF, so that proteins of different charges can migrate toward the detector end.
