The effect of mobile phase on protein retention and recovery using carboxymethyl dextran-coated zirconia stationary phases

We have examined the effect of mobile phase conditions on and recovery of proteins from a carboxymethyl dextran coated zirconia stationary phase. Mobile phases containing the Lewis bases phosphate and fluoride were examined as a function of concentration. We found that proteins only eluted from the stationary phase when some minimum concentration of Lewis base was present in the mobile phase. The effect of ionic strength was also examined. We found that a fairly high ionic strength is needed to elute the proteins with good recovery. The concentrations of the Lewis bases and the ionic strength needed to elute the proteins depended on the identity of the protein and the Lewis base. The pH of the mobile phase also plays a role; when the pH of the system is below the isoelectric point of a protein, it is difficult to elute that protein.