Abstract: We reported a novel method for in situ enrichment and detection phosphopeptides by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS), where nanoliter samples are directly applied on wells of MALDI plate adsorbed magnetic Fe₃O₄/TiO₂ nanoparticles for incubation, rinsed to remove unbound species, and followed by MS analysis. The advantages of this
method include no loss of samples because of no transference for samples to be a
nalyzed, easiness of operation, high throughput and robustness.