Method for magnetic separation featuring magnetic particles in a multi-phase system

A method of separating at least one target substance from at least one non-target substance in a test fluid, comprising the steps of:

• mixing the test fluid with a quantity of first and second magnetic particles to produce a suspension comprising a magnetic component and a non-magnetic component, wherein the magnetic component comprises first magnetic particles bound to said at least one target substance through at least one substance on the surface of the first magnetic particles which directly or indirectly binds to said target substance and second magnetic particles which possess properties necessary for the formation of a phase which contains both the magnetic and non-magnetic components and which is distinct from a magnetically inert fluid phase of a liquid system in which the separation of target substance occurs, and the non-magnetic component comprises the remainder of the test fluid, including the non-target substance;
• establishing the magnetically inert fluid phase in a container having a collection surface therein;
• introducing said suspension into the container as a stable phase which is distinct from the magnetically inert phase, to confine the magnetic and non-magnetic components of the suspension within the distinct phase;
• generating in the container, a gradient magnetic field having a region of sufficiently high intensity adjacent to the collection surface to cause disintegration of the distinct phase into its constituent magnetic and non-magnetic components;
• attracting the distinct phase toward the collection surface;
• disintegrating said distinct phase in said high intensity region;
• collecting the magnetic component of the disintegrated distinct phase upon the collection surface when the distinct phase disintegrates;
• and
• removing the non-magnetic component of the disintegrated distinct phase away from the collection surface, thereby separating said at least one target substance from at least one non-target substance.

A method of controlling the movement of a substance within a magnetically inert fluid medium, comprising:

• mixing said substance with a quantity of magnetic particles which possess properties necessary for the formation of a phase which is distinct from and stable in said magnetically inert fluid medium to form a suspension;
• introducing said suspension into said fluid medium as a distinct phase from said fluid medium;
• applying a magnetic field to the fluid medium, said magnetic field having a gradient within said fluid medium sufficient to attract said distinct phase and having an intensity that is sufficiently low to prevent disruption of said distinct phase;
• and
• altering the position of said magnetic field within said fluid medium to effect a desired movement of said distinct phase therein.