Hydrothermal synthesis of α-Fe2O3@SnO2 core-shell nanotubes for highly selective enrichment of phosphopeptides for mass spectrometry analysis

In this work, we synthesized alpha-Fe2O3@SnO2 core-shell structure nanotubes by a facile two-step hydrothermal method for selective enrichment of phosphopeptides. The core-shell structure nanotubes were found to have outer diameters of 90-110 nm, thicknesses of 30 nm, and lengths of 260-280 nm. SnO2 nanoparticles with an average crystallite size of around 5 nm form a layer of about 10 nm on both walls of the alpha-Fe2O3 nanotubes. To demonstrate their ability for selective enrichment of phosphopeptides, we applied alpha-Fe2O3@SnO2 nanotubes to the isolation and enrichment of the phosphopeptides from standard protein digestion and real samples. The enriched peptides were analyzed by MALDI-MS and LC-ESI MS. Experiment results demonstrate that SnO2 coated alpha-Fe2O3 nanotubes show excellent potential for selective enrichment of phosphopeptides.