Spectrophotometric Determination of Aspirin by Transacetylation of 4-Aminophenol

Article abstract of DOI:10.1021/ac00295a037

Aspirin transacetylates 4-aminophenol, yielding acetaminophen (N-acetyl-4-aminophenol), which can be determined by its oxidation to an orange-yellow product either by iodylbenzene in acetone when the absorbance is measured at 430 nm or by photometric titration with 2-iodylbenzoate in acetone-water medium at 444 nm.Salicylic acid, salicylamide, oxyphenbutazone, caffeine, and sodium hydrogen carbonate do not interfere.Drug mixtures of acetaminophen and aspirin have been analyzed by determining acetaminophen alone directly with iodyl reagents and then determining acetaminophen plus aspirin after 4-aminophenol reaction; aspirin is found b y difference