What chemicals are used in the preparation of Mayer hematoxylin?

• A. Sodium iodate and ammonium aluminum sulfate
• B. Sodium iodate alone
• C. Ammonium aluminum sulfate alone
• D. Ferric chloride

Answer: (A)

Mayer hematoxylin relies on forming the active hematein mordant complex that binds nuclei. The oxidizing agent converts hematoxylin to hematein in situ, and the mordant binds that oxidized form to tissue so the stain is retained. Sodium iodate provides the oxidation, turning hematoxylin into hematein, while ammonium aluminum sulfate acts as the mordant that complexes with the hematein and fixes it to nuclear material, producing the characteristic blue-black nuclear stain. Ferric chloride is not part of Mayer’s formulation, and using it or using only one component would either fail to oxidize or fail to fix the stain properly.