Veterinary Drugs Residue Methods


Category Antibacterial substances, including sulfonamides and quinolones
Drug Class Name Sulfonamides
Method Title Determination and Confirmation of Sulfonamides
Method Date 2009/09/25
Method Type Confirmatory, Quantitative
Scope and Application This method is suitable for analysis of multiple sulphonamides (Sulfathiazole, Sulfadiazine, Sulfamerazine, Sulfachloropyridazine, Sulfamethazine, Sulfamethoxazole, Sulfisoxazole, Sulfaquinoxaline, Sulfaethoxypyridazine, Sulfatroxazole, Sulfaphenazole, Sulfadimethoxine, Sulfadoxine) in liver and meat/muscle. Sulfapyridine is used as an internal standard.
Method Summary Methanol extract of centrifuged sample (from a determinative TLC procedure) is evaporated to dryness and dissolved in ethyl acetate (should diazomethane be used to methylate the sulfonamides). Some diazomethane is evaporation and PFPA in hexane added before agitating the mixture. Diethylamine in ethyl acetate is also added to acylate the sulfonamides. The sample extract is then carefully evaporated (avoiding loss of volatile derivatized sulphonamides) before adding ethyl acetate in cyclohexane. 1 M (pH 6.8) phosphate buffer is the added and the mixture centrifuged. The aqueous bottom layer is quickly removed, excess water is removed from the extract using sodium sulfate prior to a final centrifugation step. An aliquot of the resulting organic layer is then analysed using GC/MS-EI in SIM mode. A fused silica capillary analytical column is used to separate the analytes
Applicable Concentration Range The minimum proficiency level is 50 µg kg-1.
QC Requirements See attached SOP
Method Source USDA-FSIS
Method SOP PDF icon SOP