Ti/IrO2 as anode and Zr as cathode in multicompartment electrolyzers with Immobiline membranes

Multicompartment electrolyzers with isoelectric Immobiline membranes are used for large-scale preparative protein purification. A series of isoelectric membranes, of defined pI values, is utilized for keeping any desired species isoelectric within each compartment of the electrolyzer. It is preferable to have electrode disks of the same surface area as the membranes for a proper performance of the instrument because electrolyte solutions of low conductivity are used. The use of Pt disks would be quite expensive; we therefore propose using Zr as a cathode and Ti/IrO2 as an anode in the electrodic compartments. This pairing of electrodes seems to give the same performance as Pt wires. Also, conventional isoelectric focusing, as well as isoelectric focusing in immobilized pH gradients, both requiring a good contact area between gel and electrodes, would benefit by using flat laminae of these metals as electrodes.