Preparation and characterization of a novel biporous spherical ion-exchanger for protein adsorption

A novel biporous spherical matrix of poly (glycidyl methacrylate-co-ethylene dimethacrylate) was prepared by suspension polymerization with superfine granules of calcium carbonate as solid porogenic agent and cyclohexanol plus dodecanol as solvent porogenic agents. After being functionalzed with diethylamine, the matrix (denoted as matrix A) was used as an anion exchanger for protein adsorption. The types and concentration of dispersing agents, the amount of calcium carbonate and solvent porogenic agents, as well as cross-linking agents for the preparation of the matrix had been optimized. It was found that in matrix A the macropores (> 180 nm) took 37.9% of all the pore volume,while in the beads (matrix B) prepared with only solvent porogenic agents 86.8% of the pore volume was in the range 4 similar to 180 nm. Due to the presence of the macropores, convective flow occurred through matrix A in chromatography, leading to a high dynamic capacity up to 51.6 mg(.)g(-1) (wet resin) at a flow rate as high as 25 cm(.)min(-1), nearly 4 times higher than that of matrix B. Moreover, the column of matrix A showed much lower backpressure than that of matrix B. These results indicated the potential application of the biporous matrix in high-speed chromatography for protein separation.