Separation and characterization of complex crude mixtures produced in the synthesis of therapeutic peptide hormones by liquid chromatography coupled to electrospray mass spectrometry (LC–ES-MS)

Native peptides and peptidomimetics can be synthesized in a routine way by rapid and efficient procedures. However, the final products always result in complex mixtures, in which the target peptide is contaminated with undesired side products and other impurities. Thus, it is imperative to develop analytical methods for the evaluation of the target peptideʹs purity in order to obtain an effective, safe and legal pharmaceutical product. LC–ES-MS is used here in order to separate and characterize the side-products associated with several synthetic hormones with therapeutic interest: carbetocin, eledoisin, leuprolide, goserelin and triptorelin. General directions for LC–ES-MS analysis of the synthetic peptide mixtures are established. Mass information obtained offers a significant advantage for the purity assessment of therapeutic hormones and gives a key tool to enhance their process of synthesis.