A PARTIALLY AUTOMATED PRETREATMENT MODULE FOR ROUTINE ANALYSES FOR 17NONSTEROID ANTIINFLAMMATORY DRUGS IN RACE HORSES USING GAS-CHROMATOGRAPHY MASS-SPECTROMETRY

A partially automated module for the routine determination of illicit non-steroid antiinflammatory drugs (NSAIDs) in biological fluids from race horses was built, tested, refined, and shown to work. This pretre atment module retains 17 NSAIDs on an Amberlite XAD-2 column before ba ck-elution derivatization with methyl iodide in acetonitrile. Methylat ed derivatives are manually injected into a gas chromatograph connecte d to a mass spectrometer. The quantification limits thus achieved are 50-100 ng/mL in 1 mL of urine or plasma. The proposed method is more e xpeditious than its manual liquid-liquid and liquid-solid extraction c ounterparts and is similar in speed to a typical gas chromatographic p rogram.