In Ehrlich's Hematoxylin, what can be added for immediate ripening?

• A. Sodium iodate
• B. Ammonium Aluminum Sulfate
• C. Mercuric Oxide
• D. Glycerol

Answer: (A)

Immediate ripening in Ehrlich's hematoxylin refers to speeding up the oxidation of hematoxylin to hematein so it can promptly form the blue-black complex with the aluminum mordant and stain nuclei consistently. Sodium iodate acts as the oxidizing agent that rapidly ripens hematoxylin, enabling quick, stable nuclear staining. The aluminum salt (ammonium aluminum sulfate) serves as the mordant to form the hematein–mordant lake, but it isn’t the agent that drives ripening. Glycerol is mainly a solvent/humectant and doesn’t accelerate ripening, and mercuric oxide isn’t the standard choice for immediate ripening in this stain protocol.