Delafield's Hematoxylin contains glycerol; what is its purpose?

• A. Protection from overoxidation
• B. Acts as a mordant
• C. It is a solvent for hematoxylin
• D. It preserves tissue moisture

Answer: (A)

Glycerol in Delafield's hematoxylin acts as a stabilizer that protects the stain from overoxidation. Hematoxylin must be oxidized to hematein in the presence of ferric ions to bind properly to tissue. If oxidation occurs too rapidly or unevenly, nuclei can stain inconsistently or fade over time. Glycerol slows this oxidation and helps keep the solution from drying out, preserving color intensity and producing a more uniform, durable blue‑purple nuclear staining. It isn’t functioning as the mordant or the main solvent, and its role isn’t simply to keep tissue moist during staining.