Separation and characterization of multicomponent peptide mixtures by liquid chromatography-electrospray ionization mass spectrometry. Application to crude products of the synthesis of leuprolide

Leuprolide is a synthetic structural analogue of luteinizing hormone-releasing hormone used for the treatment of a large number of diseases related with the regulation of sexual hormones. Solid-phase peptide synthesis is used to obtain leuprolide peptidic hormone, but this synthetic procedure results in complex mixtures that need separation and characterization. Here, liquid chromatography coupled with mass spectrometry using electrospray ionization, (LC–ES-MS), was used for the separation and characterization of multicomponent peptide mixtures of crudes of synthesis of leuprolide. To optimize the LC separation process, the method of linear solvation energy relationships was applied and the powerful coupling LC–ES-MS permitted rapid and reliable characterization of the reaction product.