Veterinary Drugs Residue Methods


Category Antibacterial substances, including sulfonamides and quinolones
Drug Class Name Sulfonamides
Method Title Screening of Sulfonamides by Automated Robotic Extraction and Thin Layer Chromatography (TLC)
Method Date 2012/02/24
Method Type Screening
Scope and Application This method can be used to screen for the presence of sulfamethazine, sulfathiazole, and sulfadimethoxine in tissue (porcine, bovine caprine and avian muscle and liver), processed products, eggs, and egg products.
Method Summary Liver and muscle samples are homogenized in ethyl acetate and centrifuged. Eggs and egg products are thoroughly mixed in ethyl acetate and centrifuged as well. After adding 3.2M HCl and vortexing, the ethyl acetate is discarded and hexane added. After shaking, the hexane layer is also discarded before adding 3.5 M sodium acetate followed by ethyl acetate again. Centrifugation is repeated, the extracts mixed with diethylamine solution, evaporated to dryness and reconstituted in methanol before spotting onto the pre-absorbant layer of LK6D thin layer plates. Developement is done in methanol followed by chloroform/t-butanol (80:20) after drying the plate. The plate is then dipped in fluorescamine and scanned using a densitometer (410 plus or minus 10nm excitation)
Applicable Concentration Range The sulfonamides sulfamethazine, sulfathiazole, and sulfadimethoxine may be detected at the concentration level ≥ 50µg kg-1 in the matrices above.
QC Requirements See uploaded SOP
Method Source USDA-FSIS
Method SOP PDF icon SOP 
Citation USDA-FSIS Chemistry Laboratory Guidebook