How ligand and particle types affect retention and separation of structurally diverse biologically active compounds in HPLC

In this work, effects of particle and ligand types on retention and separation of sets of neutral (naphthoflavones), acidic (profens), basic (cathinones), and zwitterionic (dipeptides) biologically active compounds are shown in detail and discussed. Nine columns differing in ligand and particle types were tested, namely XSelect HSS C18, XSelect HSS C18 SB, XSelect HSS PFP, XSelect CSH C18, XSelect CSH Phenyl-Hexyl, XSelect CSH Fluoro-Phenyl, XBridge C18, XBridge Shield RP18, and Atlantis PREMIER BEH C18 AX. Various mobile phases differing in acetonitrile/aqueous part volume ratio and aqueous part pH, i.e. pH = 2.1, pH = 4.7, and pH = 8.0 were tested and compared in terms of analytes´ retention and separation. Results showed significant effect of ionic interactions resulting from particle types used or additional ionisable functional groups bonded to the surface on retention and separation of charged compounds. All tested sets of compounds were baseline separated but different conditions, that is column type and mobile phase composition, were needed. Graphic abstract: