Two oxidizing agents are used in Schiff reaction for unsaturated lipids.

• A. Performic and peractic acid
• B. Nitric and acetic acid
• C. Permanganic and chromic acid
• D. Hydrogen peroxide and ozone

Answer: (A)

In this Schiff reaction for unsaturated lipids, staining depends on turning carbon–carbon double bonds into aldehyde groups that will react with Schiff reagent to give color. Using mild, in situ generated peracids—performic acid and peracetic acid—provides just that kind of oxidation: they cleave the double bonds to form aldehyde ends without excessive breakdown of the lipid structure. Those aldehyde groups then react with Schiff reagent to produce the magenta staining that highlights unsaturated lipid areas.

Other oxidants would either over-oxidize and fragment the lipids or fail to generate the needed aldehyde groups in a controlled way, so they aren’t as suitable for this specific staining approach.