High-pressure liquid chromatographic separation, identification, and determination of sulfa drugs and their metabolites in urine.

A high-pressure liquid chromatographic method for the separation and quantitative determination of sulfamethazine, sulfathiazole, and their N4-acetylated metabolites on an amino-bonded reversed-phase column was developed. The method is suitable for the analysis of these compounds in pure solutions as well as in cattle urine. Retention times were reproducible. Injection volumes containing 0.2 mug of individual sulfonamides or their acetyl derivatives were successfully quantitated; coefficients of variation ranged from 0 to 0.073 for individual sulfonamides.