Question

______ act as solvent in polychrome staining solution.

• A. Methanol
• B. Ethanol
• C. H₂SO₄
• D. HCl

Answer 1

Answer:

A. Methanol

Role of Methanol in Staining

• Methanol (Methyl Alcohol) is the primary solvent used in polychrome staining solutions, such as Giemsa, Wright’s, and Leishman stains.

• It serves a dual purpose in these procedures: acting as both a fixative for the blood smear and a solvent for the dye components.

• The alcohol ensures the cells are attached to the slide and prevents them from washing off during the subsequent staining steps.

Key Characteristics

• Stabilization: Methanol is chemically essential because it prevents the acidic and basic dye components (like Eosin and Methylene Blue) from precipitating or reacting with each other prematurely within the solution.

• Evaporation Rate: It has a suitable evaporation rate, which is critical for the fixation process on microscope slides.

• Solubility: Most Romanowsky dyes are highly soluble in methanol, making it the ideal vehicle for these complex staining mixtures.