High Sensitivity Measurement of Pancreatic Polypeptide and Its Variant in Serum and Plasma by LC-MS/MS

Aliquots of serum or plasma samples are combined with stable isotope labeled internal standard. Pancreatic polypeptide (PP) and its truncated variant PP3-36 are enriched by incubation with anti-PP antibody conjugated to magnetic beads. Peptides are eluted from beads in acidic buffer and the samples analyzed using liquid chromatography coupled with tandem mass spectrometry. Instrumental analysis of PP and PP3-36 is performed using electrospray ionization ESI in positive ion mode and multiple reaction monitoring (MRM) acquisition.