Patent ID: 7442779

Claim:
A method for the isolation of proteins from a solution containing one or more proteins, comprising the following operations: a) contacting a solution containing one or more proteins having a pH in the range of 2.0 to 10.0 and a total salt content corresponding to an ionic strength of at the most 2.0 with a solid phase matrix comprising a functionalized matrix backbone carrying a plurality of functional groups of the following formula M-SP1-L wherein M designates the matrix backbone; SP1 designates a spacer; L designates a mono- or bicyclic optionally substituted aromatic or heteroaromatic moiety; wherein the aromatic or heteroaromatic moiety and/or SP1 is carrying an acidic group selected from the group consisting of a carboxylic acid group (-COOH), a sulfonic acid group (-SO 2 OH), sulfinic acid group (-S(O)OH), phosphinic acid group (-PH(O)(OH)), phosphonic acid monoester groups (-P(O)(OH)(OR)), and phosphonic acid group (-P(O)(OH) 2 ), with the proviso that the molecular weight of the ligand-spacer arm (SP1-L) is at the most 500 Dalton: and the ligand concentration is in the range of 10-120 μmol/ml hydrated, sedimented solid phase matrix; whereby at least a part of the proteins becomes bound to the solid phase matrix; then b) separating the solid phase matrix having proteins bound thereto from the solution; c) optionally washing the solid phase matrix; and d) contacting the solid phase matrix with an eluent in order to liberate one or more of the proteins from the solid phase matrix, with the further proviso that the following criteria are fulfilled: (i) the solid phase matrix has a binding efficiency of at least 50% when tested at a pH in the range of 2.0 to 10.0 in the Standard Immunoglobulin Binding Test; and (ii) the stability of the solid phase matrix in 1 M NaOH is such that incubation of the matrix in 1 M NaOH in the dark at room temperature for 7 days reduces the binding efficiency at a pH in the range of one pH unit lower than the binding maximum pH value to one pH unit higher than the binding maximum pH value, as determined in the Standard Immunoglobulin Binding Test, by less than 25% compared to a corresponding non-incubated matrix, wherein the pH of the eluent is in the range of 6.0 to 11.