Zirconia layer coated mesoporous silica microspheres used for highly specific phosphopeptide enrichment

Zirconia layer coated mesoporous silica microspheres with mesostructured cellular foams (MCFs) were prepared by NH3/water vapor-induced internal hydrolysis method. Zirconia layer coated MCF microspheres were characterized by SEM, XRD, N2 sorption, UV, and chromatographic analysis, and explored for enrichment of phosphopeptides. ZrO2/MCF microspheres in solid-phase extraction (SPE) mode demonstrated much higher selectivity and higher efficiency towards phosphopeptide enrichment than bulk ZrO2 particles. In particular, the selectivities of ZrO2/MCF microspheres towards multi-phosphopeptides are even higher than that of the widely used commercial TiO2 microparticles. The ZrO2/MCF microspheres were also applied to enrich endogenous phosphopeptides from human serum, and twelve endogenous phosphorylated peptides could be specifically enriched.