Mass spectrometry of anabolic steroids as their tert-butyldimethylsilyl ether derivatives

The aim of the present study was the development of an improved method for derivatization of anabolic steroids. A suitable derivative should facilitate identification of anabolic steroids and their metabolites in human urine without using reference standards. Compared with commonly used trimethylsilyl ether derivatives, tert-butyldimethylsilyl ether derivatives were found to give an increased production of the molecular ion and diagnostic ions above m/z 300 upon electron impact massspectrometry. The bulky tert-butyldimethylsilyl group could also be introduced into the sterically crowded 17-position of anabolic steroids, This was accomplished simultaneously with enolization of 3-keto functionalities by unsing small amount of tert-butyldimethylsilyl triflate as a catalyst, The versatility of the presented method is demonstrated by derivatization and full scan mass spectra of urine metabolites of anabolic steroids.