Phosphonic Acid Functionalized Periodic Mesoporous Organosilicas and Their Potential Applications in Selective Enrichment of Phosphopeptides

Phosphonic acid functionalized periodic mesoporous organosilicas were synthesized by co-condensation of 1,2-bis(trimethoxysilyl)ethane and diethoxyphosphoryiethyl-triethoxysilane in acidic medium using Brij-76 as a template. Structural characterizations showed that the mesoporous materials with 2-D hexagonal mesostructures could be obtained in the presence of an inorganic salt, NaCl. The results of transmission electron microscopy revealed that the materials synthesized with NaCl/Brij-76 mass ratios of 3 and 4 had extensive structural defect holes in the nanochannels. After coordinating metal ions (Zr4+ and Fe3+) with phosphonic acid in the mesopore, the materials were applied as the potential immobilized metal affinity chromatographic adsorbent for the selective enrichment of phosphopeptides. Because of the stronger affinity interaction between the coordinated metal ions and the phosphoryl groups of phosphopeptides, the higher surface area, and the unique mesoporous structure, the capture of the phosphopeptide on the phosphonic acid functionalized periodic mesoporous organosilicas were much more efficient than that on the commercial POROS-20 beads.