Electrokinetic separation of peptides and proteins using a polyvinylamine‐coated capillary with UV and ESI‐MS detection

Abstract

In order to accomplish the analysis of peptides and proteins by capillary electrophoresis, Lupamin, a high-molecular-weight linear polyvinylamine (PVAm) polymer, was introduced to modify the inner wall of fused-silica capillaries by physical absorption. Thanks to the high density of positively charged amino groups in Lupamin under acidic conditions, not only is a strong reversed electroosmotic flow generated in the coated capillary but the adsorption of analytes on the inner wall of the capillary is also efficiently eliminated. It has been demonstrated that the Lupamin-coated capillary can be used to advantage for the rapid analysis of amino acids, peptides, and proteins with good resolution and peak shape by capillary electrophoresis. In order to evaluate the basic feature of a Lupamin-coated capillary, electroosmotic flows generated by a Lupamin coating layer under different conditions including pH, coating time, concentration, and the composition of electrolytes on Lupamin-coated and uncoated capillaries were investigated. Furthermore, electrospray ionization-mass spectrometry (ESI-MS) detection was carried out for the analysis of amino acids and peptides.