shown adjacent to and below containment wall 37 when the cover plate is closed over the well and attached to the base plate it is preferred that the top surface 35 of the containment wall 37 seals against the lower surface of the cover slip however the locking member 60 may also be used to help seal the sample within the sample tab should any leakage occur past the containment wall 37 the embodiment shown in fig3 shows a hinged cover plate however it is to be understood that cover plate 40 comprising locking member 60 may be separate from base plate 45 and the cover plate may be attached to the base plate after a sample is introduced into well 10 since the cover plate is attached to the base plate the final sample tab assembly serves as one unit if it is required that the sample be effectively sealed within well 10 then the upper surface of containment wall 37 may be modified to comprise a sealing member 35 for example an u201c o ring u201d that fits within a grooved upper surface of the containment wall the top surface of the containment wall 37 may be made of a softer pliable material for example silicon yet integral.