Method from separating magnetic particles in fluid includes: in the interior compartment that the fluid mixture comprising liquid medium, biological components and magnetic-particle is introduced into container by entrance Allow at least part of the mixture to surround the marker space being formed in the interior compartment to advance, and the interior compartment is then left by the outlet on opposite sides in the marker space Apply magnetic field with the mixture into the interior compartment, so that the magnetic-particle is retained in the container or its interior compartment by the magnetic field. The marker space is by such as by welding or pressing for good and all or reversibly upper container wall and lower chamber wall are fixed together and are formed between the inlet, so that the medium and biological components have to be around the marker space and flow and pass through the magnetic field, to leave the interior compartment by the outlet.
