Which two hematoxylins contain ammonium or potassium aluminum sulfate?

• A. Mayer and Harris
• B. Mayer and Ehrlich's
• C. Harris and Weigert's
• D. Mayer only

Answer: (A)

The concept being tested is the mordant used in hematoxylin stains. Hematoxylin needs a mordant to form a stable complex that binds to nuclei, and aluminum salts are common mordants in several standard formulations. Mayer’s hematoxylin uses a potassium aluminum sulfate mordant, and Harris’s hematoxylin uses an aluminum salt (aluminum ammonium sulfate). Because both rely on aluminum-based mordants, they contain ammonium or potassium aluminum sulfate. In contrast, Weigert’s hematoxylin uses an iron mordant (ferric chloride), and Ehrlich’s hematoxylin uses a different formulation, not aluminum-based. Therefore, the two that contain ammonium or potassium aluminum sulfate are Mayer’s and Harris’s.