N-methyl-N-alkylsilyltrifluoroacetamide-I-2 as a new derivatization reagent for anabolic steroid control

Analytical methods for the control of growth promoters have to be specific and sensitive. At low concentration levels, it is difficult to identify som e molecules unambiguously even with the improved performance of analytical methods. CC-MS analysis of 17 beta-trenbolone and its major metabolite, 17 alpha-trenbolone, is a good example. A new derivatization agent has been de veloped which is based on silylation of the 3- and 17-oxygenated functions and nucleophilic substitution in the 4-position. The structure of the deriv atized products was demonstrated using a simple model, cyclohex-2-en-1-one, by NMR and MS spectrometry. In contrast to data found in the literature, t his derivative permitted specific mass spectra for trenbolone, sensitive si gnals for high mass ions and reproducible gas chromatograms to be obtained. The addition of an N(CH3)COCF3 radical to the steroid nucleus allowed high ly specific detection in CC-high resolution MS even following extraction fr om complex matrices; sensitive responses were also observed in the negative chemical ionization mode. Moreover, then are significant differences in th e electron ionization mass spectra:of the two stereoisomers, 17 alpha- and 17 beta-trenbolone. These preliminary results and those obtained for andros ta-1,4-dien-3-one and pregna-4,6-dien-3-one indicate useful advances for th e determination of steroids and potential applications for metabolism studi es on such compounds.