Mass spectrometry of steroid glucuronide conjugates. I. Electron impact fragmentation of 5 alpha-/5 beta-androstan-3 alpha-ol-17-one glucuronides, 5 alpha-estran-3 alpha-ol-17-one glucuronide and deuterium-labelled analogues

Owing to the developments of analytical instruments and interfaces (e.g. co upling high-performance liquid chromatography to mass spectrometry), there has been increased interest in new reference materials, for example in dopi ng analysis with steroid glucuronide conjugates. The synthesized reference material has to pass several characterization steps including the use of ga s chromatography/mass spectrometry (GC/MS) for its structure confirmation. In the present study, the fragmentation and mass spectrometric behaviour of several steroid glucuronide conjugates of endogenous and anabolic steroids after derivatization to pertrimethylsilylated products and to methyl ester pertrimethylsilylated products were investigated using GC/MS ion trap and GC/MS quadrupole instruments. The mass spectra of the derivatives of andros terone glucuronide, ns-androsterone glucuronide, epiandrosterone glucuronid e, etiocholanolone glucuronide, 11 beta -hydroxy etiocholanolone glucuronid e, 19-norandrosterone glucuronide, d(4)-19-norandrosterone glucuronide and l alpha -methyl-5 alpha -androstan-3 alpha -ol-17-one glucuronide are prese nted and the origin of typical fragment ions of the glycosidic and steroida l moieties is proposed, based on different derivatization techniques includ ing derivatization with d(18)-bistrimethylsilylacetamide, methyl ester and trimethylsilyl ester derivatization and selected reaction monitoring. Typic al fragmentation patterns which are related to the steroid structure are di scussed. Copyright (C) 2001 John Wiley & Sons, Ltd.