Magnetic chromatography of magnetic fine particles suspended in a liquid with a steel-bead column under a periodically intermittent magnetic field

The magnetic chromatography of magnetic fine particles has been proposed using a periodically intermittent magnetic field. A separation column packed with magnetically permeable steel beads is inserted into the center hole of an electromagnetic coil. The steel beads are coated with a polytetrafluoroethylene film, and the column is vibrated at ca. 10 Hz in order to minimize any irreversible adsorption of the magnetic particles on the beads. Ethanol is used as a mobile phase, and the iron oxide magnetic particles in the mobile phase are continuously monitored by flame atomic absorption spectroscopy. An elution peak for magnetite particles is delayed with increasing coil current and loading ratio of the magnetic field, while that for hematite particles is not influenced by the magnetic field. The effects of various parameters on the retention time for the magnetite particles are discussed from a theoretical viewpoint.