Sections cut for TEM must be exceedingly thin (50-100 nm). The embedding polymer must therefore be hard enough to hold the material together in an ultrathin specimen as well as to provide sufficient resistence to the electron beam.

Polymer constituents are in liquid form and should be mixed in specific volumetric proportions depending upon the desired hardness of the plastic.
 

Embedding Media Constituents	Volumes for  Consistency	Soft	Medium	Hard
Embed 812  (polymer resin)		20 ml	20 ml	20 ml
DDSA  (cross linker)		22 ml	16 ml	9 ml
NMA  (hardener)		5 ml	8 ml	12 ml
DMP-30  (accelerator)		.70-.94 ml	.66-.88 ml	.62-.82 ml

 

1. Bottles of constituents should be warmed to 60° C prior to pipetting in order to reduce their viscosity.
2. Volmetric despensing should be done with plastic disposable pipettes using a hand or automatic pippetter and into a plastic disposable beaker.
3. A magnetic stir bar and mixer should be used to produce a well-mixed and completely homogeneous solution.
4. Embedding media should be poured into plastic syringes for easy dispensing into vials or embedding molds.