Dextran conjugates are purified through chromatography and a combination of ultrafiltration methods, dialysis, and precipitation techniques. Gel filtration chromatography separates dextran conjugates by their molecular weight and size. Ion exchange chromatography may also be used. This method separates dextran conjugates by their charge. Dialysis is used to remove excess reagents, salts or small molecules from dextran conjugates. Ultrafiltration is a technique that uses pressure to differentiate molecules based on size. Precipitation involves adding a specific solvent to the conjugate solution to cause it to form a precipitate that can be separated from excess reagent.