Preparation of a TiO 2 -NH 2 modified MALDI plate for on-plate simultaneous enrichment of phosphopeptides and glycopeptides.

In this work, a TiO2 film was prepared on a MALDI plate by atomic layer deposition (ALD) technique and then modified with –NH2. The obtained TiO2-NH2 modified plate was applied for on-plate simultaneous enrichment of phosphopeptides and glycopeptides. The ALD TiO2 film displayed quite uniform morphology, and attached firmly to the MALDI plate with rather stable physical and chemical properties, which resulted in fine stability of the plate in performance. The -NH2 groups offered the film better hydrophilicity and affinity toward glycopeptides. The on-plate simultaneous enrichment performance of the TiO2-NH2 modified plate was investigated by β-casein digests, HRP digests and human serum.