Which solvent is used to remove wax during processing?

• A. Xylene
• B. Ethanol
• C. Acetone
• D. Toluene

Answer: (A)

Removing paraffin wax from tissue sections, known as deparaffinization, relies on a solvent that dissolves paraffin (a nonpolar, water-insoluble substance). Xylene is the standard choice because it effectively dissolves paraffin and prepares the tissue for rehydration and staining. Ethanol is used for dehydration and rehydration steps, not for dissolving wax. Acetone can dissolve wax but is less favored due to its strong dehydrating action and faster evaporation, which can affect tissue integrity. Toluene can dissolve wax as well, but it’s less commonly used in routine processing because of toxicity considerations and other practical drawbacks. Therefore, xylene best serves to remove wax during processing.