title: Application of the ammonia gas-sensing electrode: determination of drugs having a carboxyamide group by decomposition with acid.
abstract: A simple potentiometric method for the determination of drugs having a carboxyamide group is described. Ethenzamide, niacinamide, pyrazinamide, or salicylamide was refluxed with 20% HCl and the carboxyamide was hydrolyzed. The ammonia evolved at a pH greater than 11 and was determined without separation from the decomposition solution using an ammonia gas-sensing electrode. A linear calibration plot was obtained with drugs in the range of 2 x 10(-5) - 1 x 10(-2) M. This method was applied to the analysis of injection and powder-containing auxiliary compounds.
mesh_terms: D000577:Amides / Q000032:analysis*; D000641:Ammonia / Q000032:analysis*; D055598:Chemical Phenomena; D002621:Chemistry; D004566:Electrodes; D006851:Hydrochloric Acid; D006868:Hydrolysis; D009536:Niacinamide / Q000032:analysis; D011208:Powders / Q000032:analysis
chemical_list: D000577:Amides; D011208:Powders; D009536:Niacinamide; D000641:Ammonia; D006851:Hydrochloric Acid