Efficient enrichment of glycopeptides with sulfonic acid-functionalized mesoporous silica.

This work presents an efficient and selective enrichment method for glycoprotein/glycopeptides with sulfonic acid-functionalized mesoporous silica (SBA-15-SO3H), which is synthesized via simple oxidation of -SH groups with H2O2. The functionalized SBA-15 shows large surface area and accessible pores, and can selectively adsorb glycopeptides via hydrogen bond and hydrophilic interaction. Upon the selective enrichment prior to the mass spectrometric (MS) analysis, the signals of glycopeptides are significantly enhanced, which leads to the identifiable signals of 21 glycopeptides from the digest of HRP, 16 glycopeptides from the digest of human IgG, and 16 glycopeptides from the digest of chicken avidin. The SBA-15-SO3H gives significant selectivity for glycopeptides even at a low molar ratio of glycopeptides to nonglycopeptides with an enrichment time of 15min. Therefore, this work provides a powerful material for selective enrichment and identification of low abundant glycopeptides in glycoproteomic analysis.