One-step fabrication of nitrogen-rich linear porous organic polymer-based micron-sized sphere for selective enrichment of glycopeptides.

In this work, nitrogen-rich linear porous organic polymers (POPs) were designed to improve glycopeptides enrichment efficiency in HILIC. Two kinds of novel POPs (CH-pPAL and CH-mPAL) were one-step prepared via the Schiff-base condensation reaction and intermolecular hydrogen-bonded using a flexible amine monomer (carbohydrazide, CH) to react with two aldehyde monomers, p-phthalaldehyde (pPAL) and m-phthalaldehyde (mPAL), respectively. The specific surface area of CH-pPAL and CH-mPAL was 238 and 232 m g, respectively. Based on the hydrogen-bond interaction, several narrow peaks existed in the PXRD patterns. Particularly, micron-sized spherical CH-pPAL possessed a honeycomb-like orderly tunnel structure. The contact angle of CH-pPAL and CH-mPAL severally was 35.4° and 28.8°, respectively, indicating excellent hydrophilicity of as-synthesized POPs. They both demonstrated high sensitivity and high adsorption capacity in glycopeptides enrichment. The 851 and 794 unique glycopeptides derived from 170 and 200 N-glycosylated proteins were identified after the enrichment by CH-pPAL and CH-mPAL within three independent replicates of proteins extracted from human serum, respectively. Therefore, these CH-based hydrophilic POP materials would be applied in the enrichment and identification of low-abundance N-linked glycopeptides from complicated biological samples.