Millon's Test

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Millon’s Test


a color reaction test used to detect the presence of proteins; first observed by the French chemist A. E. Millon in 1849. A purplish-red deposit is precipitated upon heating a protein solution containing Millon’s reagent (a solution of mercuric nitrate in nitric acid, with an admixture of nitrous acid). The reaction is caused by the presence of phenol radicals in the amino acid tyrosine, which is a constituent of proteins.