In Delafield's Hematoxylin, what is the role of alcohol?

• A. Preservative
• B. Mordant
• C. Solvent for hematoxylin
• D. Humectant

Answer: (A)

Alcohol in Delafield's hematoxylin acts as the solvent for the dye. Hematoxylin is not readily soluble in water, so dissolving it in ethanol creates a stable, evenly distributed staining solution that can penetrate tissue and deliver the dye to nuclei. The staining relies on oxidation to form hematein and then a dye–mordant complex to fix the color in the nuclei; the mordant itself is a separate component, while the alcohol’s primary job is dissolving and delivering the hematoxylin (and helping maintain solution stability so the stain remains usable). Humectants or preservatives aren’t the main role of the alcohol in this formulation.