I want to do resin embedding of a soil sample using Araldite. It is important for me to compromise between spatial and chemical integrity. In order to first dehydrate my sample after fixation, I will not use acetone because it washes off organic compounds. I want to know that which solvent can better dissolve Araldite, ethanol or methanol. In another words, which one is better for dehydration step, methanol or ethanol?
Thanks
Epoxy resins are suitable media for embedding for electron microscopy, as they set uniformly with virtually no shrinkage. A mixture of epoxy resins has been developed which is soluble in ethanol and which yields a block of the required hardness for thin sectioning. For more details consult https://www.science.gov -topic pages.
Drying of soil samples before embedding them in a resin is an essential step if you want to preserve the fabric of an undisturbed soil sample. It can be more crucial id the sample has a higher clay content. We have performed two methods:
1. Shock freezing and subsequent freeze drying of the sample: this method may produce cracks in the fabric especially at higher clay amount
2. Displacement of water using a series of ethanol/acetone mixtures starting with pure ethanol, then 75% ethanol/25% acetone, then 25% ethanol/75% acetone and finally 100 % acetone applied for 24 h in each step: Ethanol displaces water better then acetone since the molecule resembles the one of water. If you cannot work with acetone you might try it only with ethanol but you have to wait longer until it is volatilized.
We have made good experiences using Araldit but have used other epoxy resins as well. However, we have only applied various ketones as solvents. I don't think that Araldit is well soluble in ethanol or methanol.
Thanks for the suggestions, dear Ute Kalbe. I think in our case maybe the second option will be better. I will try it.
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