Lead Sulfide Test- Definition, Principle, Procedure, Result, Uses


Lead sulfide test is a biochemical test that detects the presence of sulfur-containing amino acids, such as cysteine and cystine, in a given sample. The test is based on the reaction of sulfur with lead acetate under alkaline conditions, resulting in the formation of a black precipitate of lead sulfide. The test is also known as lead acetate test, as lead acetate is the main reagent used in the test. The test is specific for amino acids that have free sulfur atoms in their side chains, such as cysteine and cystine. However, methionine, another sulfur-containing amino acid, does not give a positive result in this test. The test can be used to identify proteins that contain cysteine and cystine residues, as well as to detect cystine in urine samples. The test is simple, rapid and inexpensive, and can be performed in a laboratory or at home.