Ligand-exchange chromatography of amino acids on nickel-Chelex 100

A ligand-exchange chromatographic proceudre for the selective separation of amino acids from inorganic ions is presented. It was found that the binding of amino acids to the nickel-Chelex 100 resin is pH dependent. At pH 8.5-9.1, only the basic amino acids lysine, histidine and arginine are quantitatively attached to the complex, whereas at pH 11, other amino acids with the exception of aspartic acid and glutamic acid are also bound, although not quantitatively. All of the amino acids can be eluted from the complex with 3 M ammonia solution without the displacement of nickel ions from the complex. This method can be used for the removal of the basic amino acids from solutions in the presence of inorganic ions as well as other amino acids.