ELECTROSPRAY MASS-SPECTROMETRY OF TESTOSTERONE ESTERS - POTENTIAL FORUSE IN DOPING CONTROL

The study described involves an attempt to identify 17 beta-fatty acid esters of testosterone in blood plasma following administration of su ch agents. These drugs are therapeutic bur are increasingly misused by athletes in an attempt to improve sports performance. The mass spectr al properties of testosterone esters under electrospray ionization are described. These esters (testosterone acetate, propionate, isocaproat e, benzoate, enanthate, cypionate, phenylpropionate, decanoate, and un decanoate) essentially give only a protonated molecular ion (MH+) unde r ''optimum sensitivity'' mass spectrometric conditions but could be i nduced to fragment in the source or collision cell of a triple quadrup ole mass spectrometer. The underivatized steroid esters were analyzed by direct infusion because development of solvent systems compatible w ith high-performance liquid chromatography (HPLC) was not achieved for these nonpolar compounds. HPLC/MS (mass spectrometry) was possible wh en the steroids were converted to polar; water soluble, Girard hydrazo nes, and almost all compounds were separated by microbore C-4 HPLC usi ng a water acetonitrile, TFA gradient. The mass spectra under optimal ionization conditions essentially comprised only a molecular ion (M+), but source fragmentation gave major ions at M-59 and M-87 for all com pounds. The molecular ion and these fragment ions were monitored in a selected-ion-recording (SIR) method developed for defecting the steroi ds in plasma. Using this methodology, testosterone enanthate and undec anoate could be detected after intramuscular injection or or al admini stration of the drugs. Further development of the technique could form the basis of a protocol for confirming the misuse of testosterone in sport, especially if sensitivity could be improved. (C) 1997 by Elsevi er Science Inc.