Xanthoproteic Test- Definition, Principle, Procedure, Result, Uses


Xanthoproteic test is a biochemical test that detects the presence of amino acids that have phenolic or indolic groups in their structure. These amino acids are called aromatic amino acids because they contain benzene rings or other aromatic compounds. Examples of aromatic amino acids are phenylalanine, tyrosine, and tryptophan.

The name xanthoproteic test comes from the Greek word xanthos, which means yellow. This is because the test produces a yellow precipitate of xanthoproteic acid when the amino acids react with nitric acid. The yellow color is due to the nitration of the aromatic groups by nitric acid. The nitration reaction also makes the amino acids more soluble in alkali, which turns the solution orange.

The xanthoproteic test is a qualitative test, which means that it only tells whether the amino acids are present or not. It does not measure the amount or concentration of the amino acids. The test is useful for identifying and differentiating aromatic amino acids from other types of amino acids.