Determination of leakage from antibody adsorbent: composition analysis and pH effect

To study the leakage at different solution pH values, IgG Sepharose 6FF®, a commercially available immunoadsorbent, was used as a model. The leaked substance consists of three parts: (1) ligands and its fragments; (2) ligands plus matrix fragments in which ligands are chemically attached to the adsorbent matrix; and (3) matrix fragments. Buffer solution pH values had a great effect on both the kinetics and the amount of ligand leakage. Cross-linking of the adsorbent matrix could reduce both matrix leakage and antibody leakage at pH 3.0, but its effect was limited at pH 11.0 for ligand leakage.