Simultaneous high-performance liquid chromatographic determination of residual sulphamonomethoxine, sulphadimethoxine and their N4-acetyl metabolites in foods of animal origin.

A rapid and sensitive method for the determination of residual sulphamonomethoxine, sulphadimethoxine and their N4-acetyl metabolites in beef, pork, chicken and eggs by high-performance liquid chromatography (HPLC) was developed. The extraction of these compounds was performed using a mixture of 90% (v/v) acetonitrile solution and hexane (5:4, v/v) to minimize the fat content followed by purification by alumina column chromatography. These extracts contained sulphonamide analytes which were free from interfering compounds when examined by HPLC using a LiChrosorb RP-18 column. The average recoveries from spiked meat and egg were in excess of 80% with relative standard deviations between 0.4 and 5.0%. The practical limits of detection were 0.01 ppm for all samples.