Gradient and isocratic high-performance liquid chromatography of proteins on a new agarose-based anion exchanger

We describe a new, simple, and mild method for the preparation of anion exchangers, based on the coupling of alkylamines to epoxy-activated agarose (prepared by the reaction of agarose with butanediol diglycidyl ether). Since a polar OH-group is formed when an epoxide reacts with an OH or NH2 group, the ion-exchanger did not show any hydrophobic interaction. This is important, since it may be impossible to desorb a protein from an ion exchanger having a hydrophobic character, because increasing the salt concentration of the eluent to decrease the electrostatic binding inevitably strengthens the hydrophobic interaction.