Determination of small amounts of some sulfonamide drugs by resonance raman spectrometry

Resonance Raman spectrometric determinations of eight sulfonamide drugs are discussed. All the samples were colorless and exhibited no resonance Raman effect with argon ion laser excitation. After conversion to colored derivatives by diazotization and coupling reactions of the aromatic primary amine moiety, the sulfonamides could be determined from their resonance Raman spectra; the detection limits were about 2 × 10^-3 M. However, the method cannot be used for identification of the individual drugs because the spectra obtained exhibited exactly the same spectral features. In order to obtain characteristic spectra, color development for the R—NH₂ molecule produced by hydrolysis of the sulfonamide with hydrochloric acid was examined. Three of the samples tested (sulfathiazole, sulfisoxazole and sulfisomezole) gave colored derivatives by a common chemical reaction system; the resonance Raman spectra then obtained exhibited characteristic spectral patterns.