A general use cleaning procedure is as follows: 3- 5CV of 0.1-0.5M sodium hydroxide, followed by 3-5CV of 0.5-1mol/L sodium chloride before column equilibration. Toyopearl and TSK-GEL resins can withstand caustic for well up to 8 hrs at a time. Be sure to operate at reasonable flow rates to avoid over pressuring as the resin will swell in the presence of base. Maximum pressure limit for Toyopearl resins is 3 bar (45psi) and for TSK-GEL resins is 20 bar (300psi).

Removing Protein

In some cases, protein may be tightly bound to the resin.

• In cases where protein is bound ionically, follow the hydroxide wash with 5CV of water then 3-5CV of 0.1-0.5M hydrochloric acid before washing with salt.
• In cases where protein is bound hydrophobically to either HIC or SEC resin, wash the resin with 3-5CV of water, followed by 3-5CV of 20% methanol or acetonitrile. Rinse with 3-5CV of water before following the general use cleaning procedure.

Cleaning Affinity Resins

In regards to the affinity resins, the AF-Chelate resin may be cleaned following the general use cleaning procedure while the more ligand sensitive resins should be cleaned with any combination of salt, chaotrope (Urea/ Guanidine HCl), or detergents (Triton/ Tween). In extreme cases of tightly bound protein, the AF Heparin may be cleaned with 2CV of 0.5M sodium hydroxide as a last resort.