The statement 'Sodium iodate and ammonium aluminum sulfate are used to adjust the pH of hematoxylin' is:

• A. True
• B. False
• C. Not sure
• D. Not applicable

Answer: (B)

In hematoxylin staining, the active staining chemistry hinges on oxidizing hematoxylin to the form that binds to tissue and then using a mordant to trap it in place. Sodium iodate serves as an oxidizing agent that converts hematoxylin to hematein, the form that forms the stain complex. Ammonium aluminum sulfate provides the mordant, forming the hematein-aluminum complex that binds to nuclear structures. The pH of the hematoxylin solution is adjusted with separate buffers or acids (such as acetic acid) to achieve the desired staining characteristics, not by these two reagents. So, these substances aren’t used to adjust pH, making the statement false.