Observation of "Rhumann's purple "is confirmatory test for the presence of :

Options

A. Starch
B. Reducing sugar
C. Protein
D. Cupric ion

Answer

C

Explanation

Ninhydrin is often used to detect `prop` - amino acids and also free amino and carboxylic acid groups on proteins and peptides. When about 0.5 mL of a 0.1% solution of ninhydrin is boiled for one or two minutes with a few mL of dilute amino acid or protein solution, a blue color develops. Ninhydrin degrades amino acids into aldehydes, ammonia, and `CO_2` through a series of reactions, the net result is ninhydrin in a partially reduced form hydrindantin,

Ninhydrin then condenses with ammonia and hydrindantin to produce an intensely blue or purple pigment, sometimes called Ruhemann.s purple: