A block polymer coating with anti-nonspecific protein adsorption and pH-responsive for online enrichment of glycoproteins in capillary electrophoresis.

In this work, the poly (glycidyl methacrylate)-b-poly (phenylboronic acid) block polymer-coated capillary column was developed for the selective enrichment of glycoproteins in capillary electrophoresis. The polymer coating was fabricated through a two-step consecutive surface-initiated atom transfer radical polymerization (SI-ATRP) using glycidyl methacrylate (GMA) and 3-acrylamidophenylboronic acid (AAPBA) as monomers. The coating was characterized by techniques including Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), inverted fluorescence microscopy, scanning electron microscopy (SEM), and electroosmotic flow (EOF) analysis. Evaluations of the column demonstrated that the coating exhibits both anti-nonspecific absorption property and high enrichment towards glycoproteins. The sensitivity enhancement factor (SEF) for immunoglobulin G (IgG) reached 351.89, representing a 173.3-fold improvement over the bare fused silica capillary. The coated column could be used repeatedly for approximately 60 consecutive runs. The relative standard deviations (RSD) of peak area for intra-day (n = 5), inter-day (n = 5), and batch-to-batch (n = 3) were 3.5%, 3.6% and 4.6%, respectively. The method was successfully applied to the online enrichment of glycoproteins in a 1×106-fold diluted egg white sample, thereby confirming its practical applicability.