Which oxidizer is used in the technique shown in the image?

• A. Potassium permanganate
• B. Periodic acid
• C. Hydrogen peroxide
• D. Sodium hypochlorite

Answer: (B)

In this staining method, the oxidizer’s role is to convert sugar-containing structures into aldehyde groups so Schiff reagent can bind and produce color. Periodic acid specifically oxidizes vicinal diols in carbohydrates to form aldehydes, which is precisely what Schiff reagent detects, giving the characteristic magenta color. Other oxidizers like potassium permanganate, hydrogen peroxide, or sodium hypochlorite either tend to over-oxidize, bleach, or act non-specifically, which would alter or destroy the tissue or fail to create the needed aldehyde groups. That targeted, aldehyde-forming action is why periodic acid is the best choice here.