Assay of Aspirin,Ethenzamide and Caffeine Mixture by 13C NMR Spectrometry

¹³C FT NMR method of gated decoupling without NOE was applied in the quantitative analysis of aspirin, ethenzamide and caffeine mixture (antipyretic). Spectra were obtained in pyridine-d⁵, containing anisole as an internal standard and chromium(III) acetylacetonate as a paramagnetic relaxation reagent, The results were generally satisfactory.