Cationized hydroxyethylcellulose as a novel, adsorbed coating for basic protein separation by capillary electrophoresis.

We present cationized hydroxyethylcellulose (cat-HEC) synthesized in our laboratory as a novel physically adsorbed coating for CE. This capillary coating is simple and easy to obtain as it only requires flushing the capillary with polymer aqueous solution. A comparative study with and without polymers was performed. The adsorbed cat-HEC coating exhibited minimal interactions with basic proteins, providing efficient basic protein separations with excellent reproducibility. Under broad pHs, the amine groups are the main charged groups bringing about a global positive charge on the capillary wall. As a consequence, the cat-HEC coating produced an anodal EOF performance. A comparative study on the use of hydroxyethylcellulose (HEC) and cat-HEC as physically adsorbed coatings for CE are also presented. The separation efficiency and analysis reproducibility proved that the cat-HEC polymer was efficient in suppressing the adsorption of basic proteins onto the silica capillary wall. The long-term stability of the cat-HEC coating in consecutive protein separation runs has demonstrated the suitability of the coating for high-throughput electrophoretic protein separations.