Patent attributes
An apparatus and method of manufacture for a pipette tip having a membrane filter includes a pipette tip having an interior annulus for receiving an exterior perimeter of the membrane filter. A shear plate overlying the pipette tip defines an aperture having a dimension equal to the exterior perimeter of the membrane filter. A cylindrical punch has a path of motion for passing through the aperture in the shear plate to the interior annulus of the pipette tip. Membrane filter material is placed over the shear plate in the path of motion of the cylindrical punch. By the expedient of moving the cylindrical punch through the membrane filter material, the aperture in the shear plate, to the interior annulus of the pipette tip to place sheared filter material over the annulus of the pipette tip. Specific embodiments of pipette tips are illustrated including tips having a first filter for filtering material drawn into the pipette tip and second filters from preventing contamination of the pipette.
