title: Application of the ammonia gas-sensing electrode: determination of drugs having a carbothionamido group by decomposition with acid.
abstract: A method to determine drugs having a carbothionamido group using an ammonia gas-sensing electrode is described. To obtain analytical accuracy, the effect of factors that influence the potential is also discussed. Ethionamide or prothionamide was refluxed with 20% HCl to give ammonium chloride, hydrogen sulfide, and a carboxylic acid. The ammonia, which evolved at pH greater than 11, was determined. A linear calibration plot was obtained within the drug concentration range of 2 X 10(-5)--1 X 10(-2) M.
mesh_terms: D000577:Amides / Q000032:analysis; D000641:Ammonia / Q000032:analysis*; D055598:Chemical Phenomena; D002621:Chemistry; D004340:Drug Contamination; D004566:Electrodes; D012492:Salts; D013607:Tablets / Q000032:analysis; D013871:Thiones / Q000032:analysis*
chemical_list: D000577:Amides; D012492:Salts; D013607:Tablets; D013871:Thiones; D000641:Ammonia