title: Colorimetric assay of urinary 5-hydroxy-3-indoleacetic acid.
abstract: We describe a method for 5-hydroxy-3-indoleacetic acid in urine based on its reaction with nitrosonaphthol in the presence of mercaptoethanolamine, an odorless compound. Mercaptoethanolamine shifts the color maximum from 540 nm to 640 nm, intensifies the color and discharges the color of interfering substances. The method is rapid and free from interferences.
mesh_terms: D000082:Acetaminophen; D000328:Adult; D002276:Carcinoid Tumor / Q000652:urine; D003124:Colorimetry / Q000379:methods; D006801:Humans; D006897:Hydroxyindoleacetic Acid / Q000652:urine*; D008624:Mercaptoethylamines / Q000494:pharmacology; D009284:Naphthols / Q000494:pharmacology; D009603:Nitroso Compounds / Q000494:pharmacology
chemical_list: D008624:Mercaptoethylamines; D009284:Naphthols; D009603:Nitroso Compounds; D000082:Acetaminophen; D006897:Hydroxyindoleacetic Acid