What does the ammonia responsible for in best carmine?

• A. As a solvent for carmine to help maintain the high pH
• B. As a fixative
• C. As a decolorizer
• D. As a dehydrating agent

Answer: (A)

The key idea is that Best carmine relies on an alkaline environment to work. Ammonia serves to dissolve the carmine dye and, crucially, to raise and maintain a high pH in the staining solution. That alkaline condition enables the dye to interact with carbohydrate-rich structures such as glycogen, mucopolysaccharides, and basement membranes, producing a strong, selective stain. It isn’t acting as a fixative, a decolorizer, or a dehydrating agent.