The present invention relates generally to glutathione derivatized beads which are adapted for use in conjunction with glutathione-S-transferase fusion proteins for use in flow cytometry. The device also comprises a sleeve which can be pushed over the aforementioned region of the connecting piece, at least partially covering said piece and leaving room between the sleeve and the connecting piece for the suction hose. The first connecting member is coaxially fixed to the first shaft. The front surface of each panel has an adhesive preapplied to an edge of the panel.