Isoelectric focusing apparatus

Apparatus for isoelectric focusing, comprising, in combination:

• an enclosure having a plurality of inlet ports and a plurality of associated outlet ports opposing said inlet ports;
• a plurality of recirculation paths, each coupling an outlet port to a respective inlet part;
• a fluid within said enclosure and said recirculating paths, said fluid containing buffering components capable of establishing a pH gradient in an electric field;
• inlet and outlet separator means for respectively separating the flow of fluid which enters at said inlet ports and exists at said outlet ports;
• a plurality of ion non-selective permeable membranes disposed between respective ones of said inlet and outlet separator means and oriented generally parallel to the direction of flow of said fluid so as to streamline the flow of fluid as between said inlet and outlet separator means while allowing interchange of fluid constituents therebetween;
• means for applying an electrical potential transverse the direction of flow of said fluid in said enclosure to establish a gradient of pH steps as between successive channels defined by said membranes;
• a multichannel pump for pumping the fluid in said recirculation paths;
• a heat exchanger coupled to said recirculation paths for cooling the fluid therein;
• and
• sensing means coupled to said recirculation paths for sensing the properties of the fluid in said recirculation paths.