A series of hyperbranched polyesters with pentaerythritol as the core were; synthesized and coated on the inner surface of fused-silica capillaries by chemical bonding. Three kinds of basic proteins were selected for studying the behavior of the adsorption to fused-silica capillaries. Comparative studies of the coating materials were conducted, and the experimental results showed that the coated columns with hyperbranched polyesters could suppress the electroosmotic flow greatly and effectively prevent adsorption in the pH range of 4-6; they were superior to capillaries coated with traditional hydroxypropyl cellulose. Furthermore, research was conducted to study the effect of hyperbranched polyester generation of the column efficiency. The results showed that higher coated efficiency was obtained on a capillary column coated with the sixth generation of the hyperbranched polyester at pH 5.0. (C) 2008 Wiley Periodicals, Inc. J Appl Polym Sci 111: 2141-2147, 2009