Merck, 45345-250ML-F, Epoxy embedding medium

Sigma-Aldrich Epoxy Embedding Medium is a viscous resin used to prepare biological tissue specimens for thin sectioning and electron microscopy. The formulation serves as an Epon 812 substitute and can penetrate dehydrated samples before the resin is cured into a rigid embedding block. Appropriate anhydride hardeners and an amine accelerator are added separately to produce the selected hardness and polymerization characteristics. The 250 mL product is an individual resin component, not a complete multicomponent embedding kit. Tissue preparation commonly includes fixation, graded solvent dehydration and resin infiltration before embedding. Control residual moisture because water can interfere with the embedding process, and mix the complete resin formulation thoroughly to obtain uniform hardening. Cure the specimen using conditions suitable for the tissue and selected hardener ratio, then assess block integrity before ultramicrotomy. Handle the uncured material under appropriate chemical-safety controls and prevent contamination of the stock container. This embedding medium must not be confused with the DDSA or MNA hardener bottles sold separately.