How would you test an unknown solutions for protein?

Answer 1

The biuret test is a chemical test used for detecting the presence of peptide bonds. In the presence of peptides, a copper(II) ion forms violet-colored coordination complexes in an alkaline solution.[1] Several variants on the test have been developed.

The Biuret reaction can be used to assay the concentration of proteins because peptide bonds occur with the same frequency per amino acid in the peptide. The intensity of the color, and hence the absorption at 540 nm, is directly proportional to the protein concentration, according to the Beer-Lambert law.

Answer 2

To test an unknown solution for protein, you can use a biuret reagent test. Mix the unknown solution with the biuret reagent, and observe any color change. A purple color indicates the presence of protein in the solution. If the color change does not occur, it suggests that there is little or no protein present.