Determination of Dexamethasone in Milk by High Pressure Liquid Chromatography

Abstract

A rapid and sensitive high pressure liquid chromatographic method for the analysis of dexamethasone (9α-fluoro-11β,17α,21-trihydroxy-16α-methylpregna-1,4-diene-3,20-dione) in milk has been developed. The corticosteroid can be quantitated at 20 ppb, with the limit of detectability estimated at 5 ppb. Recoveries ranged from 72 to 94%. After dexamethasone was injected into 5 Holstein-Friesian cows, no residues were found in milk, even after the first milking.