Detection of anabolic steroids by GC/SIM/MS with trifluoroacetylation in equine plasma and urine

A method to detect three anabolic steroids (boldenone, nandrolone and meste rolone) is presented. The anabolic steroids are isolated from equine plasma and urine by extraction with diethyl ether and C-18 Sep-Pak cartridge adso rption, respectively. The extracts obtained were derivatized with trifluoro acetyl anhydride and analyzed by GC/SIM/MS. The selected ion monitoring (SI M) mode was applied to increase the sensitivity and, when possible, the hig her m/z ions were selected to improve identification. Stability of derivati ves was good and compounds having hydroxy and conjugated ketone groups prod uced trifluoroacetyl ester derivatives that were also stable. Repeatability of the chromatographic analysis was evaluated on the basis of area repeata bility, and the coefficient of variation obtained was lower than 4.4. The d etection limit was 1 and 5 ng/ml for all the anabolic steroids studied in e quine plasma and urine, respectively.