The reproducibility of the oxime chemistry and ATRP technology based enrichment were also crucial for obtaining reliable glycopeptides identification and quantification. As shown in Figure 5 and Table S1-3, 21.4% N-glycoprotein and 25% deglycosylated N-glycopeptides were identified in three replicates tests demonstrating good reliability of this enrichment method. These results indicate the application potential of this method in N-glycoproteins/glycopeptides separation and enrichment.