Affinity purification of polypeptide on protein A matrix

Process for purifying an anti-VEGF antibody or an antibody fragment comprising the region antigen-binding thereof, which comprises a CH2 / CH3 region, from a contaminated solution thereof by Protein A chromatography, which comprising: (a) adsorbing the antibody or antibody fragment to Protein a immobilized on a solid phase comprising silica or glass; (B) removing contaminants bound to the solid phase by washing the solid phase with a hydrophobic electrolyte solvent, wherein the hydrophobic electrolyte solvent comprises tetrapropylammonium chloride, tetrabutylammonium chloride, tetramethylammonium chloride (TMAC) or tetraethylammonium chloride ( TEAC); and (c) recovering the antibody or the antibody fragment from the solid phase.