Fabrication of Piperazine Functionalized Polymeric Monolithic Tip for Rapid Enrichment of Glycopeptides/Glycans.

Enrichment strategies are designed for the pretreatment of low-abundance glycans and glycopeptides prior to mass spectrometric (MS) analysis. Here, a tip-based strategy is being reported for the enrichment of glycopeptides and glycans using a piperazine modified polymeric monolithic tip. The tip is fabricated using the free radical polymerization. Fast separation (2 min) is achieved under optimized conditions with 20 cycles per step of loading, incubation, washing, and elution followed by MALDI-MS analysis. A total of 25, 22, and 34 glycopeptides covering all glycosylation sites are enriched by the modified tips from tryptic digests of horse radish peroxidase, chicken avidin, and human immunoglobulin G, respectively. Piperazine exhibits high selectivity 1:400 horse radish peroxidase/bovine serum albumin, sensitivity to 100 attomoles, recovery 89.51%, and batch to batch reproducibility (RSD > 1) in glycopeptides enrichment. Piperazine tips also enrich glycans from ovalbumin and human immunoglobulin G. High selectivity (1:1200, ovalbumin/BSA) and detection limit of 100 attomole is attained for glycans and furthermore 58 glycans are enriched from human serum. Thus, piperazine tips can be used as an enrichment tool for swift, cost-effective routine analysis of biological samples for separation of glycopeptides and glycans.