A use of a ligand-functionalized substrate for purification of a target biomolecule, wherein the ligand-functionalized substrate comprises: a. A substrate having carboxylic (-COOH), hydroxy (-OH), thio (-SH), amino groups (-NH2), C-C double bonds (-ene) or C-C triple bonds (-yne) at the surface thereof; b. Covalently bound to said carboxylic (-COOH), hydroxy (-OH), thio (-SH), amino groups (-NH2), C-C double bonds (-ene) or C-C triple bonds (-yne) of said substrate a linker having a linker length of 10-25, such as 17-22 bonds, wherein bonds are C-C, C-N, C-N(H), C-C(O) and/or C-O; and c. A ligand-functional group bound to the surface of the substrate via said linker; the purification comprising the steps: (a) contacting (i) a target biomolecule, (ii) a dual affinity polypeptide, and (iii) the ligand-functionalized substrate, and (b) recovering the target biomolecule by elution, wherein the target biomolecule and the dual affinity polypeptide are contacted in solution before the mixture is contacting the ligand-functionalized substrate, and optionally (c) washing away impurities and/or removing the dual affinity polypeptide, wherein said ligand-functional group and said linker are selected from the group consisting of: wherein the ligand-functionalized substrate comprises: a. A substrate having carboxylic (-COOH), hydroxy (-OH), thio (-SH), amino groups (-NH2), C-C double bonds (-ene) or C-C triple bonds (-yne) at the surface thereof; b. Covalently bound to said carboxylic (-COOH), hydroxy (-OH), thio (-SH), amino groups (-NH2), C-C double bonds (-ene) or C-C triple bonds (-yne) of said substrate a linker having a linker length of 10-25, such as 17-22 bonds, wherein bonds are C-C, C-N, C-N(H), C-C(O) and/or C-O; and c. A ligand-functional group bound to the surface of the substrate via said linker; a. A substrate having carboxylic (-COOH), hydroxy (-OH), thio (-SH), amino groups (-NH2), C-C double bonds (-ene) or C-C triple bonds (-yne) at the surface thereof; b. Covalently bound to said carboxylic (-COOH), hydroxy (-OH), thio (-SH), amino groups (-NH2), C-C double bonds (-ene) or C-C triple bonds (-yne) of said substrate a linker having a linker length of 10-25, such as 17-22 bonds, wherein bonds are C-C, C-N, C-N(H), C-C(O) and/or C-O; and c. A ligand-functional group bound to the surface of the substrate via said linker; the purification comprising the steps: (a) contacting (i) a target biomolecule, (ii) a dual affinity polypeptide, and (iii) the ligand-functionalized substrate, and (b) recovering the target biomolecule by elution, wherein the target biomolecule and the dual affinity polypeptide are contacted in solution before the mixture is contacting the ligand-functionalized substrate, and optionally (c) washing away impurities and/or removing the dual affinity polypeptide, (a) contacting (i) a target biomolecule, (ii) a dual affinity polypeptide, and (iii) the ligand-functionalized substrate, and (b) recovering the target biomolecule by elution, wherein the target biomolecule and the dual affinity polypeptide are contacted in solution before the mixture is contacting the ligand-functionalized substrate, and optionally (c) washing away impurities and/or removing the dual affinity polypeptide, wherein said ligand-functional group and said linker are selected from the group consisting of: <EOS>