Microwave processing uses which solvent for dehydration and clearing because it is miscible with paraffin wax?

• A. Isopropyl alcohol
• B. Ethanol
• C. Xylene
• D. Water

Answer: (A)

In microwave tissue processing, the solvent used for dehydration and clearing should be able to move into the embedding medium, meaning it must be miscible with paraffin wax. Isopropyl alcohol fits this role because it both displaces water during dehydration and mixes with paraffin, enabling rapid transition from the dehydrated tissue to the wax during microwave processing. This compatibility allows faster clearing and infiltration in a single system, speeding up processing without needing a separate clearing solvent that isn’t compatible with paraffin.

Water wouldn’t work because it isn’t miscible with paraffin and would block infiltration. Ethanol is good for dehydration but is less compatible with paraffin for clearing/infiltration. Xylene clears well and is miscible with paraffin, but it’s not the solvent used for dehydration in many microwave protocols, whereas isopropyl alcohol can serve both dehydration and clearing steps in these rapid systems.