Characterization and optimization of a chromatographic process based on ethylenediamine-N,N,N',N'-tetra(methylphosphonic) acid-modified zirconia particles

Abstract

The primary objective of work was to characterize, optimize and model a chromatographic process based on ethylenediamine-N,N,N',N'-tetra(methylphosphonic) acid (EDTPA)-modified zirconia particles. Zirconia particles were produced by spray-drying colloidal zirconia. Zirconia spheres produced were further classified, calcined and modified with EDTPA to yield a solid-phase support for use in bio-chromatography (r_PEZ). Specifically, the ability of r_PEZ to selectively bind and enrich IgG, IgA, and IgM from biological fluids was evaluated and demonstrated. To better understand the force of interaction between the IgG and the r_PEZ, the equilibrium disassociation constant (K_d) was determined by static binding isotherms, as a function of temperature and by frontal analysis at different linear velocities. The maximum static binding capacity (Q_max) was found to be in the range 55-65 mg IgG per ml of beads, and unaffected by temperature. The maximum dynamic binding capacity (Q_x) was found to be in the range 20-12 mg IgG per ml of beads. The adsorption rate constant (k_a) was determined by a split-peak approach to be between 982 and 3242 l mol⁻¹ s⁻¹ depending on the linear velocity. The standard enthalpy and entropy values were estimated for this interaction of IgG with this novel support.