EPON 812 is an excellent clearing and mounting reagent for BM Purple/NBT-BCIP stained whole-mount specimen. However, one drawback is the amount of toxic waste generated during the process of getting specimen into the resin monomer.

Briefly, the sample is dehydrated through an ethanol series (50%, 70%, 80%, 90%, 95%, 100% X3). It is desirable that the specimen is incubated in 100% ethanol over an extended period of time (e.g. overnight) for best results.

Following EtOH incubation, the sample is then transferred into propylene oxide (PPO) to replace EtOH. Wash once in PPO and then transfer into 1:1 mixture of PPO and EPON 812. Allow PPO to evaporate completely. Simply sitting the tube in a hood overnight with the open lid should get this done. Note PPO is highly volatile and toxic; do not inhale PPO vapor; always handle PPO under a chemical hood. Replace EPON 812 monomer with fresh liquid. The sample is ready for view under a microscope.

EPON 812 is available as Poly/Bed-812 (Polysciences 08791-500) or EMbed-812 (Electron Microscopy Sciences 14900).

There is no need to use very pure PPO (very expensive!); EM grade (e.g. Electron Microscopy Sciences 20401) is sufficient.