Novel adsorptive polyamine coating for enhanced capillary electrophoresis of basic proteins and peptides

In capillary electrophoresis (CE), the anionic and hydrophobic nature of the fused-silica capillary surface has long been known to present a problem in protein and peptide analysis. The use of capillary surface coating is one of the approaches to avoid the analyte–wall interactions. In this study, a new polymer, poly-LA 313, has been synthesized, physico-chemical characterized, and applied as polyamine coating for CE separations. The coating process is highly reproducible and provides fast separations of peptides and proteins in a few minutes and with high efficiency. The physically adsorbed polymer gives rise to a durable coating in the range of pH 2–10, in the presence of organic modifiers (acetonitrile and methanol) and with complex biological samples. The efficiency of the new cationic polymer was also tested performing protein and peptide separations with capillary electrophoresis-electrospray ionization-mass spectrometry (CE-ESI-MS).