HisTrap(TM) ff is a ready-to-use column prepacked with precharged Ni Sepharose(R) 6 fast flow for preparative purification of histidine-tagged recombinant proteins by immobilized metal ion affinity chromatography (IMAC).Ni Sepharose(R) 6 fast flow consists of 90 mum beads of highly cross-linked agarose to which a chelating ligand has been immobilized. This chelating ligand is charged with Ni2 ions the first-choice metal ion for purifying most histidine-tagged proteins. The negligible leakage of Ni2 ions from the matrix ensures reliable capture of histidine-tagged proteins in repeated IMAC purifications.The high flow rates made possible by the Ni Sepharose(R) 6 fast flow matrix make HisTrap(TM) ff columns well suited for small scale-up. Capacity can be increased by connecting columns in series. HiTrap(R) IMAC ff is the product of choice when charging the medium with different metal ions for optimization of purification protocols.