This document summarizes a study that investigated using multimodal metal affinity chromatography to separate empty and full adeno-associated virus (AAV) capsids. The researchers found that empty capsids eluted first from the column, followed by full capsids, and then more empty capsids and debris. They evaluated the fractions using density gradient centrifugation and found that columns charged with different metal ions, including barium, calcium, magnesium, zinc, manganese, and ferric ions, gave similar separation results. Recovery of full serotype 9 capsids was 100% with complete removal of empty capsids. All metal ions also bound contaminants that required sodium hydroxide for removal, with ferric iron and manganese