Characterization of Vasoactive Intestinal Polypeptide with LC-MS/MS Method

Neuropeptides are peptides used by neurons for communication. Vasoactive intestinal polypeptide (VIP) is a polypeptide belonging to the glucagon/secretin family obtained from the hypothalamus region of the brain. In this study, VIP was analytically characterized and examined by the sensitive Liquid Chromatography-Mass Spectrometry (LC-MS/MS) method. For the analysis of VIP, chromatographic (such as separation column, organic solvent and acid content of the mobile phase, flow rate) and mass spectrometric (observation of precursor ions and fragments of peptides, fragmentation voltage, collision energy) parameters were examined. In the analysis, 665.9 (M+5) m/z precursor ion as well as 799.5 and 770.7 m/z fragment ions were observed for VIP. Moreover, the sources of the adsorption problem of the peptide that emerged during the analyzes were investigated and factors preventing adsorption were tested in LC-MS/MS analyses. Additionally, the effect of albumin solution on the analyzes as a barrier to the adsorption of the peptide to the surface was investigated. As a result of the these studies, the suitability of the application has been demonstrated in that the masses and fragments of the polycharged species of VIP in the presence of adsorption can be observed with the developed LC-MS/MS method.