Influence of magnetic field on aqueous two-phase extraction of horse ferritin in the polyethylene glycol/hydroxyethyl starch system

The presented experiments show the model of expectation of equine spleen ferritin extraction in a new aqueous two-phase system which was formed by mixing polyethylene glycol (PEG) and hydroxyethyl starch (HES). The tendency of the protein to migrate in the analyzed systems was dependent on the concentrations of HES and PEG as well as PEG molecular weight. The highest concentration of ferritin in the top phase (rich in PEG) was recorded in the system composed of 6% PEG 3000 and 3% HES. The obtained concentration was 0.88 mg mL−1. The lowest concentration was 0.42 mg mL−1 in the system composed of 5% PEG 6000 and 1% HES.Next the influence of the magnetic field on ferritin accumulation was analyzed. Selected samples were placed between homogeneous (S/S) or heterogeneous magnetic poles (N/S and S/N). It was observed that after the application of the magnetic field the extraction of ferritin into the PEG rich phase increased in every examined system. That increase was as high as 1.67-fold ferritin concentration in the PEG phase as compared with the total concentration of ferritin in the system before separation. Introduction of the magnetic field to two-phase extraction systems is shown as an effective method of changing the partition coefficient of ferritin.