A combination strategy using two novel cerium-based nanocomposite affinity probes for the selective enrichment of mono- and multi-phosphopeptides in mass spectrometric analysis.

This work presents a sequential enrichment protocol, based on two self-designed cerium-based nanocomposite affinity probes, which not only can effectively separate phosphopeptides from non-phosphopeptides but can also selectively differentiate mono- and multi-phosphopeptides for direct matrix-assisted laser desorption/ionization time-of-flight mass spectrometric (MALDI-TOF MS) analysis.