Synthesis of Magnetic Microspheres with Immobilized Metal Ions for Enrichment and Direct Determination of Phosphopeptides by Matrix‐Assisted Laser Desorption Ionization Mass Spectrometry

Core/shell structured magnetic silica microspheres with immobilized Fe3+ (see image) are prepared with a simple method. Using a magnetic field, the microspheres are quickly, efficiently, and specifically enriched. Phosphopeptide identification can then be achieved through mass spectroscopy. This is a new method for the enrichment of phosphopeptides and opens up the possibility of other new applications using the microspheres.