Patent ID: 8143071

Claim:
A method for purifying and concentrating a protein from a sample solution comprising the steps of: a) introducing the sample solution containing the protein into a first pipette tip column, wherein said first pipette tip column is comprised of a first packed bed of extraction medium, wherein the first packed bed of extraction medium is comprised of a functional group, and whereby at least some portion of the protein is adsorbed by the first packed bed of extraction medium; b) passing a wash solution through the first packed bed of extraction medium; c) passing a first desorption solvent through the first packed bed of extraction medium, whereby at least some fraction of the bound protein is desorbed from the first packed bed of extraction medium into the desorption solvent, and wherein, as a result of step (c), the protein is purified from other components in the sample solution; d) optionally adjusting the pH of the purified protein in the desorption solvent; e) introducing the purified protein into a second pipette tip column, wherein the second pipette tip column is comprised of a second packed bed of extraction medium, wherein the second packed bed of extraction medium is comprised of a functional group, wherein the functional group of the second packed bed of extraction medium is the same as the functional group of the first packed bed of extraction medium, wherein the capacity of the second pipette tip column has is in the range of 1% to 95% of the capacity of the first pipette tip column, and whereby at least some portion of the protein is adsorbed by the second packed bed of extraction medium; f) optionally passing a wash solution through the second packed bed of extraction medium; and g) passing a second desorption solvent through the second packed bed of extraction medium, whereby at least some fraction of the bound protein is desorbed from the second bed of extraction medium into the second desorption solvent, and wherein the purified protein has a concentration of at least 5 mg/ml.