Chemo-affinity of titania for the column-switching HPLC analysis of phosphopeptides.

A column-switching high-performance liquid chromatography (HPLC) system for the determination of phosphopeptides has been developed. The method is based on the selective adsorption of phosphopeptides on a titania (TiO2) precolumn and successive HPLC separation of the phosphopeptides on an anion-exchange column with a UV detector (215 nm). The recoveries of phosphopeptides were tested using authentic phosphopeptides [Gln-Ile-Ser(p)-Val-Arg, Ile-Ser(p)-Val-Arg and Lys-Gln-Ile-Ser(p)-Val-Arg] at an injection amount of 1 microg. The recoveries were 74.3, 79.6, and 82.6%, respectively, while the corresponding dephosphopeptides were not retained on the titania precolumn.