Obelisc N mixed-mode columns provide different selectivity than other HILIC columns -- presence of ion-exchange mechanism contributes to a different selectivity. Depending on the pH of the mobile phase, ion-exchange mechanism can be enhanced or suppressed. Two amino acids (glycine and glycylglycine), two basic compounds (triethanolamine and TRIS) and two zwitter-ionic compounds (MOPS and MES) are separated by combination of HILIC and ion-exchange mechanisms. Compounds elution can be monitored by Evaporative Light-Scattering Detector (ELSD), Corona (CAD), LC/MS or other detection techniques.