Phosphoproteomics: Searching for a needle in a haystack

► TiO2 MOAC is simple, fast, and provides a high selectivity towards phosphopeptides. ► IMAC is a widely used general enrichment technique; “on-plate” enrichment seems promising. ► The use of pTyr antibodies is the “reference method” for pTyr-peptide purification. ► LTQ-Obritrap is a “state-of-the-art” mass spectrometer in phosphoproteomics.