This work presents the results obtained using a microcolumn agitated by pulsed caps, using aqueous two-phase systems formed polyethylene glycol and salts (monobasic and dibasic) potassium phosphate for protein extraction. Proteins used were extracted cytochrome b5 and the enzyme ascorbic oxidoreductase. It was observed that operation of this equipment was stable and high efficiency values were achieved.

This paper describes a novel system which has a great potential for use for extractions in biotechnological processes as it uses only polymers and can be operated at moderate temperatures and salt concentrations. The polymers used in this work are ethylene oxide-propylene oxide 10:90 (w/w) (EO10PO90) and ethylene oxide-propylene oxide 20:80 (w/w) (EO20PO80). The temperature required for thermoseparation decreases with increasing PO content of the copolymer and increasing buffer concentration.