Facile fabrication of zwitterionic magnetic composites by one-step distillation-precipitation polymerization for highly specific enrichment of glycopeptides

Hydrophilic interaction chromatography (HILIC) utilizing zwitterion-modified material as solid phase has attracted extensive attention for selective enrichment of glycopeptides. However, a tedious synthesis and low specificity for glycopeptides have restricted its application. Herein, a facile and effective approach was developed to synthesize a zwitterionic (ZIC) polymer-coated magnetic composites (denoted as Fe3O4@PMSA) with a zwitterion ((2-(methacryloyloxy)ethyl)-dimethyl-(3-sulfopropyl) ammonium hydroxide, MSA) via one-step distillation-precipitation polymerization (DPP). The well-designed composites presented clearly ZIC-polymer shell and superior hydrophilicity (water contact angle 30.2), and the performance for selective enrichment of glycopeptides were investigated with standard and real samples, respectively. Owning to the abundant of ZIC molecules with multi-charge and polar groups on the surface of resulting polymer coating, the Fe3O4@PMSA demonstrated high selectivity for glycopeptides enrichment with IgG digest (twenty glycopeptides identified, S/N ≥ 20) and a mixture of IgG and BSA at the mass ratio of 1:230 (sixteen glycopeptides identified, S/N ≥ 20). Besides, the detection limit as low as 0.67 fmol for IgG (S/N ≥ 10) and satisfied recovery yield more than 74% were achieved by the proposed sorbents. Finally, the Fe3O4@PMSA was applied for enriching N-linked glycopeptides from human serum, and 348 unique N-glycosylation sites and 419 glycopeptides from 158 glycoproteins were strictly identified from 1 μL human serum. The results demonstrated that the proposed Fe3O4@PMSA showed a promising potential in glycoproteomics analysis of real biological samples.