Determination of flunixin residues in bovine muscle tissue by liquid chromatography with UV detection

A new and sensitive liquid chromatography-ultra violet method with a detect ion limit of 6 ng/g (ppb) and a limit of quantification of 15 ng/g was deve loped for the determination of flunixin residues in bovine muscle tissue, F lunixin in homogenized animal tissue was extracted with acetonitrile after enzyme digestion. The tissue digest (extract) was then cleaned up on a soli d-phase extraction cartridge and eluted with acidified hexane. After the el uate was evaporated to dryness under nitrogen at 55 degreesC, the residue w as reconstituted in 1 mi mobile phase solution and analyzed by reversed-pha se gradient chromatography with UV detection at 285 nm, The method was then applied in a survey study of slaughter animals to determine whether flunix in is being used in an off-label manner for veal and beef production in Can ada.