J Clin Lab Anal. The color change from blue to violet indicates the presence of proteins.
The Biuret test for proteins may also be extended to quantitatively measure the concentration of total protein using spectrometric methods. Shake well and allow the mixtures to stand for 5 minutes.
This biuret colorimetric method was relatively simple, fast, and accurate for the determination of protein in urine and cerebrospinal fluid, with a wide linearity extending from 0.
The peptide bonds in Biuret give a positive result for the test hence the reagent is named so. The chelate complex absorbs light at nm and hence appears violet.
The quantity of food crushed and water used depends on the number of tests to be conducted. Cupric ions or Cu II ions form a violet-colored chelate complex with unshared electron pairs of peptide nitrogen and oxygen of water.
October 16, Author Biochemistry 0 Biuret is a compound formed by heating urea at It is the result of the condensation of 2 molecules of urea.