Abstract: The invention relates to a method for improved cleaning of a first substance which is bound to paramagnetic microparticles. Said microparticles are suspended in a first liquid. The inventive method comprises the following steps: a) microparticles are exposed to a first magnetic field in a first container so that they are securely maintained and are prevented from being washed away by a flow of the first liquid, and b) after step a), at least one part of the first liquid is guided through the line in a first direction of the first line and through another section, and in the second section, said part is exposed to a second or to the first magnetic field in order to hold onto the washed away microparticles. In the section, the surface of the cross section of the first line is enlarged. The second or first magnetic field inside the section has a larger cross-sectional field strength than the first magnetic field inside the first container.

Abstract: The invention relates to compositions to be administered to a living being, a method for marking agents that are administered to living beings, the use thereof, and an accelerated test.