Abstract: A tip for use on a volumetric pipettor which tip contains a microporous membrane. The attached tip is attached to bellows and is immersed in a liquid, and the bellows of the pipettor are expanded pulling liquid through the tip to fill that portion of the tip located below the microporous membrane.

Abstract: A method of carrying out a solid phase chemical reaction or a filtration step to remove a solid from a liquid utilizing ferromagnetic particles. The particles may have a porous or otherwise bondable solid support material having adsorbed or chemically bonded thereon a biologically active substance to make them biologically active. Alternatively, the particles may act as an inert medium to convey a solid precipitate out of a liquid. The process involves the addition of the ferromagnetic particles to a potentially reactive fluid. After the fluid has reacted either as a result of contact with the biologically active material or by a process causing a precipitate in the fluid, the particles may be separated from the fluid by bringing the particles into close proximity with a magnet such as an electromagnet.