Ninhydrin Test
• A biochemical test for detecting amino acids and proteins.
• Reacts with free amino groups to produce a colored compound.
Principle
• Ninhydrin reacts with α-amino acids to form a deep blue or purple complex called Ruhemann’s purple.
• Involves decarboxylation and deamination of the amino acid, releasing CO₂ and ammonia.
Reagents Required
1. Ninhydrin solution (0.1% in ethanol or acetone).
2. Buffer solution (optional, to maintain pH).
3. Distilled water.
Procedure
1. Add 1 mL of test solution (containing the amino
acid or protein) in a test tube.
2. Add 1 mL of ninhydrin reagent to the solution.
3. Heat the mixture in a boiling water bath for 2-3 minutes.
4. Observe the color change a...