CHROMATOGRAPHY OF PROTEINS USING POLYBUTADIENE-COATED ZIRCONIA

Polybutadiene-coated zirconia (PBD-ZrO2), when used as a stationary ph ase in conjunction with a mobile phase containing phosphates, constitu tes a reversed-phase/cation-exchange mixed-mode chromatographic system . The separation of proteins on this phase can be achieved only throug h the use of mobile phases containing the correct combination of phosp horic acid, displacing salt, and organic cosolvent. We found that exce ssive Coulombic interactions between proteins and the stationary phase impair the system performance for the separation of proteins. The eff ects of mobile phase conditions on the separation of proteins using ph osphate-adsorbed PBD-ZrO2 are studied in this work. Factors such as th e presence of a multivalent cation, mobile phase pH, phosphate concent ration, and salt concentration can be manipulated to reduce the net ne gative charge on the surface and thereby improve the performance of th e system toward the separation of proteins.