What molecules can be purified by ion exchange chromatography?

Molecules that can be purified by ion exchange chromatography include proteins, nucleic acids, peptides, and small molecules. Many proteins carry net charges at a specific pH due to the presence of ionizable amino acid residues such as lysine, arginine and glutamic acid. Ion exchange chromatography can be used to separate proteins based on differences in their net charge. Like proteins, peptides contain ionizable amino acid residues and can be separated based on their charge properties. Nucleic acids such as DNA and RNA, contain negatively charged phosphate groups in their backbone. Peptides, proteins and nucleic acids can all be purified at molecular weights greater than 3000. Smaller molecules with molecular weights less than 3000 can also be purified if they carry a net charge.