Question

Which of the following tests cannot be used for identifying amino acids?
A. Biuret test
B. Xanthoproteic test
C. Barfoed test
D. Ninhydrin test

Answer 1

Hint The test can be used for the detection of monosaccharides. The compound in the test contains copper which gets reduced and a brick red precipitate is formed, when glucose is the testing material.

Complete step by step answer:
The biuret test is such a chemical test which will be accustomed to check for the presence of peptide bonds when an analyte is given. Therefore, the biuret test can be used to measure the quantity of protein that is accumulated in the given analyte.. In the duration of this test, the presence of peptides leads to the formation of coordination compounds that are pale or mauve purple coloured copper(II) ions (when the answer is sufficiently alkaline.
The Xanthoproteic test uses a nitration reaction to work out the presence of proteins during a solution. When the sample is treated with a concentrated and hot acid it reacts with aromatic amino acids like tyrosine, phenylalanine and tryptophan and forms a yellow colored product also named Xanthoprotein.
Barfoed's test is employed for distinguishing monosaccharides from reducing disaccharides. Monosaccharides, being the simplest of all, usually are said to react in about 1-2 minute while the reducing disaccharides significantly need more time which is about between 7-12 minutes to react with the reagents.
The ninhydrin test may be a chemical test which is employed to test whether a given analyte contains amines or amino acids. During this test, ninhydrin (a matter with the formula ; IUPAC name: 2,2-dihydroxybenzene-1,3-dione) is provided to a test solution of the analyte. The event of a deep blue colour indicates the presence of ammonia, primary/secondary amines, or amino acids within the analyte.The amino of the analyte forms a compound the same as diketo hydrin. This compound incorporates a deep blue colour, often observed as Ruhemann’s purple.
Hence Biuret test , Xanthoproteic test , Ninhydrin test are used for identifying Amino Acids.

Therefore option c is the correct answer.

Note: Amino acids are a bunch of organic compounds that form the building blocks of proteins that frame 75% of the body. they're involved in almost all sundry functions, including growth and development, normal digestion, healing and repair, and providing energy required in the body.