GoBio™ Mini His-tag Screening kits contain columns that are pre-packed with cross-linked agarose based resin that can be used in the purification of proteins in biotechnology research and method development. The base matrix, WorkBeads,™ is highly porous to enable optimal protein interaction. The metal ion is immobilized on the media via a chelating ligand based on iminodiacetic acid (IDA) or nitrilotriacetic acid (NTA). The resin in the column then has either Ni2+, Co2+, Cu2+ and Zn2+ immobilized on it