Question

Millon's test detects the presence of __________.

• A. lipids
• B. amino acids
• C. nucleic acids
• D. glucuronic acids

Hint:

This test reacts specifically with the phenolic ring of the amino acid tyrosine.

Answer 1

The Correct Option is B

Step 1: Millon's reagent is a solution of mercuric and mercurous nitrate in nitric acid, used as a classic qualitative test in biochemistry.

Step 2: When heated with a protein or amino acid solution, the reagent reacts with the phenolic ring of tyrosine, producing a brick-red precipitate or coloration.

Step 3: Since the test specifically responds to the tyrosine residue found in proteins and free amino acids, it is used to detect amino acids/proteins, not lipids, nucleic acids or glucuronic acids, none of which carry the phenolic group this test targets.

Step 4: So the correct answer is amino acids.