On-plate enrichment of glycopeptides by using boronic acid functionalized gold-coated Si wafer.

Boronic acid functionalized gold-coated Si wafer has been used as MALDI plate to isolate and enrich glycopeptides for MS analysis. This on-plate enrichment strategy offers good benefits due to the combination of specific selectivity through enrichment and direct manipulation on the wafer. First, solution transfer and eluting steps required in conventional enrichment strategies are not needed any more, thereby reducing sample loss during these steps. Second, the LODs of glycopeptides have been increased by two orders of magnitude. Third, non-specific bindings have not been detected even when non-glycopeptides are 100 times more than glycopeptides. Furthermore, the recovery of glycopeptide is up to 65.8% and glycopeptides even can be sensitively detected in the presence of 200 mM ammonium bicarbonate or physiological buffer PBS.