Which chemical used in Harris hematoxylin prep also stabilizes the solution?

• A. Ammonium aluminum sulfate
• B. Ferric chloride
• C. Sodium bicarbonate
• D. Water

Answer: (A)

In Harris hematoxylin, the stabilizing effect comes from the mordant that forms a color-fast complex with the dye. Ammonium aluminum sulfate supplies aluminum ions that create the alum-hematein complex, which binds strongly to tissue and resists fading. This stabilizes both the solution’s color and the staining itself, helping the nuclei stay stained during processing and illumination. Ferric chloride would mainly act as an oxidizer and could disrupt the stain, sodium bicarbonate is used more for pH adjustment rather than stabilization of the dye complex, and water is simply the solvent.