Cobalt Phthalocyanine Tetracarboxylic Acid Functionalized Polymer Monolith for Selective Enrichment of Glycopeptides and Glycans.

In this study, poly(glycidyl methacrylate-ethyleneglycol dimethacrylate) monolith functionalized with cobalt phthalocyanine tetracarboxylic acid is prepared. The polymer monolithic material is used for glycopeptides enrichment coupled with MALDI-TOF MS. By taking advantage of cobalt phthalocyanine including hydrogen bonds between isoindole subunits of phthalocyanine and glycans, coordination interaction between cobalt and glycopeptides, the monolithic material is successfully applied to the enrichment of glycopeptides efficiently and selectively. With IgG and horse radish peroxidase as the model glycoproteins, 28 and 17 glycopeptides could be identified respectively after enrichment with the monolith, only four and three glycopeptides could be obtained for direct analysis. The monolith is also employed to the digests mixture of BSA and IgG (50:1, m/m), indicating the high enrichment selectivity of glycopeptides even in the presence of a large interference ratio. The detection limit is determined to be 6.7 fmol, implying that the present method had great potential for trace sample analysis. In addition, the monolith was successfully applied to the enrichment of N-linked glycans in human serum samples, demonstrating its great potential for the analysis of glycoproteins.