Type 5A molecular sieves should be used to dry dehydration solvents for electron microscopy. Most common solvents (acetone, ethanol, and methanol, etc.) need to be
anhydrous for electron microscopy embedding work using epoxy resins, yet they have a tendency to pick up atmospheric water when bottles are opened. Molecular sieves are
used to dehydrate the solvents used in the final stages of dehydration and embedding . Molecular sieves are typically zeolite compounds that strongly adsorb water and have
carefully controlled pore sizes. While both the solvent and the water will adsorb strongly to the molecular sieve surfaces, the large surface area within the pores is only accessible to the smaller water molecules, so they are effectively removed from the solvent.
Running the solvent slowly through a column of the molecular sieves would be the most effective way to remove water but, ordinarily, dried sieves are just placed into the
bulk solvent container (about 5%-10% by volume) to remove most water. The sieve material is ceramic, so be very careful to not stir up any fines when the solvent is withdrawn since it could eventually end up damaging sectioning knives.
Regenerate the molecular sieves at 250℃ for 2 hr or more in a shallow layer. Place the container of hot, regenerated sieves on the porcelain plate of a glass desicator and place under vacuum while they cool. Put dry sieves into bottles with polyethelene cap liners to keep dry until needed. Type 5A molecular sieves will reduce water in an air stream to 0.001 mg/liter air. Residual moisture is probably higher for sieves dumped into bulk solvent containers, but functionally it is sufficiently effective in avoiding water contamination problems.
"Note：This is normal specification, in case of a particular application, specification or requirement, please contact us by email at firstname.lastname@example.org for technical information."
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