WorkBeads™ 40 NTA resins are based on the nitrilotriacetic acid (NTA) chelating group. The resin can easily be charged, before use, with a broad spectrum of divalent or trivalent transition metal ions, including Ni2+, Co2+, Cu2+ and Zn2+, Ga3+ or Fe3+. They can then be used for the Immobilized Metal Ion Affinity Chromatography (IMAC) purification of His-tagged proteins or other proteins with an affinity for metal ions. , which are immobilized via a metal chelating ligand on the chromatography resin.