A fixation step is, of course, not necessary for materials samples.
Dehydration for GMA embedments does not have to be complete because of GMA's miscibility in water. Only if the sample is saturated with water should a schedule of increasing alcohol concentration be used. This will displace most of the water with a solvent that can be replaced with plastic. Use schedule as follows:
- 70% ethanol for 10 minutes.
- 96% ethanol for 10 minutes.
- 96% ethanol for 10 minutes.
- absolute ethanol for 10 minutes.
Infiltration displaces the dehydration solvent with monomer prior to beginning the polymerization reaction. If you have a porous sample, infiltration may be needed. Nonporous samples can skip this step. Make up your infiltrating solution according to the directions from your kit. For reusable Teflon® molds for more effective heat removal are available from DDK. While complete elimination of air is not needed, sealing the molds with paraffin or plastic wrap is often done. Leave the samples at room temperature for 1 hour then at 37° C for one hour to complete polymerization.
If your embedments cannot be mounted directly to the microtome, an adapter must be attached. Place the suitable Technovit 3040 is an inexpensive media prepared by mixing 3 parts of the dry component to 1 part of the liquid component. Pour it into the adapter and polymerization will be complete within 10 minutes. The adapters will be firmly attached through a copolymerization of the Technovit 3040 with the GMA.
You are now ready to begin sectioning with glass.
