Veterinary Drugs Residue Methods


Category Non-steroidal anti-inflammatory drugs (NSAIDs)
Drug Class Name Flunixin, NSAID, a nicotinic acid derivative
Method Title Determination and Confirmation of Flunixin by HPLC/ESI-MS/MS
Method Date 2012/07/16
Method Type Confirmatory, Quantitative
Scope and Application This method is suitable for determining and confirming the presence of flunixin in bovine and porcine liver and muscle.
Method Summary Homogenized tissue is hydrolized with HCl in tubes incubated for 2 hours on a heating block set between 95 -120 degrees Celsius before cooling the mixture to ambient temperature. The pH of the hydrolysate is adjusted to 9.5 (9.30 - 9.70) using NaOH. Ethyl acetate is added to the tube prior to extraction by repeated centrifugation. The upper ethyl acetate extract is then loaded onto SCX cartridges for clean up and the analyte is eluted with methanolic ammonium hydroxide solution. This solution is evaporated to dryness and the residue reconstituted in 50 percent methanol/water. The mixture is then pressed through 0.45 micometer PTFE filters ready for analysis by LC/ESI/MSMS. An Eclipse XDB-C18 analytical column is used
Applicable Concentration Range Flunixin may be detected/quantified in bovine liver and muscle at ≥ 62.5 µg kg-1 and at ≥ 12.5 µg kg-1 concentration levels, respectively, and in porcine liver and muscle at ≥ 15.0 ppb and at ≥ 12.5 ppb, respectively
QC Requirements See attached SOP
Method Source USDA-FSIS
Method SOP PDF icon SOP 
Citation USDA-FSIS Chemistry Lab Guide Book