Selective Isolation at the Femtomole Level of Phosphopeptides from Proteolytic Digests Using 2D-NanoLC-ESI-MS/MS and Titanium Oxide Precolumns

Selective detection of phosphopeptides from proteolytic digests is a challenging and highly relevant task in many proteomics applications. Often phosphopeptides are present in small amounts and need selective isolation or enrichment before identification. Here we report a novel automated method for the enrichment of phosphopeptides from complex mixtures. The method employs a two-dimensional column setup, with titanium oxide-based solid-phase material (Titansphere) as the first dimension and reversed-phase material as the second dimension. Phosphopeptides are separated from nonphosphorylated peptides by trapping them under acidic conditions on a TiO(2) precolumn. Nonphosphorylated peptides break through and are…

• VU
  Vanderbilt University
• PU
  Pfizer UK