Selective enrichment of phosphopeptides by titania nanoparticles coated magnetic carbon nanotubes

•Titania nanoparticles coated magnetic carbon nanotubes were synthesized via simple hydrothermal reaction.•It was characterized by SEM and TEM, XRD.•The material was applied to selective enrichment of phosphopeptides for MS analysis.•It showed excellent potential for the selective enrichment of phosphopeptides.

Selective enrichment of phosphoproteins or phosphopeptides from complex mixtures is essential for mass spectrometry (MS)-based phosphoproteomics. In this work, for the first time, titania nanoparticles coated magnetic carbon nanotubes (denoted as MagCNTs@TiO2 composites) were synthesized through a facile but effective solvothermal reaction for selective enrichment of phosphopeptides. The MagCNTs@TiO2 material demonstrated low limit of detection (20 fmol), along with an exceptional great specificity to capture phosphopeptides from a tryptic digest of the mixture of a nonphosphorylated protein BSA and a phosphorylated protein β-casein with molar ratios of BSA/β-casein up to 200:1. In addition, the high magnetic susceptibility allowed convenient separation of the target peptides by magnetic separation. Experimental results demonstrated that the MagCNTs@TiO2 composites showed excellent potential for the selective enrichment of phosphopeptides for MS analysis.