The present invention relates to a method of purifying a protein of interest from its fusion analog, comprising obtaining a protein solution comprising a protein of interest and its fusion analog; adjusting the pH and/or ionic strength of the protein solution with an appropriate buffer for use with a Hydrophobic Charge Induction Chromatograph (HCIC) resin, contacting the protein solution and HCIC resin column to allow binding of the protein of interest and its fusion analog, washing the resin and eluting the protein of interest from the resin by a pH gradient; wherein the protein of interest is substantially free of its fusion analog.