Preparation of Bi0.15Fe0.15TiO2 Nanocomposites for the Highly Selective Enrichment of Phosphopeptides

Abstract

Novel Bi_0.15Fe_0.15TiO₂ nanocomposites (B_0.15F_0.15TNs) were synthesized for the first time by a modified sol-gel technology and successfully applied to selective extraction and enrichment of phosphopeptides from digested protein mixture solutions and real samples (tissue protein extract from human liver). The codoping of Bi and Fe into TiO₂ results in a significant enhancement in both the enrichment efficiency and selectivity. Compared with the commercial available TiO₂ extractant, the proposed B_0.15F_0.15TNs possess a lower detection limit (2 × 10^-9 M) and higher selectivity at a low weight ratio of 1:1200 (phosphopeptides/nonphosphopeptides). Additionally, a total of 223 phosphorylation sites were identified from the human liver lysate after enrichment by the B_0.15F_0.15TNs. In addition, the synthesis of B_0.15F_0.15TNs is quite easy, of high yield, and inexpensive.