Collision‐induced dissociation of 3‐keto anabolic steroids and related compounds after electrospray ionization. Considerations for structural elucidation

Abstract

The collision-induced dissociation of forty-one 3-keto anabolic steroids and related compounds has been studied using both triple quadrupole (QqQ) and hybrid quadrupole-time of flight (QTOF) instruments. Due to the complexity of the product ion spectra of these analytes, which generate a large number of ions, only two specific regions were studied in depth: the product ions near the precursor ion (m/z > or =M-100) and the most abundant product ions at a collision energy of 30 eV. Accurate mass measurements were used in order to obtain an unequivocal assignment of the empirical formula and the origin of each selected product ion. Analytes have been divided into eight groups according to the number and position of double bonds and the presence of functional groups such as hydroxyl- or nitrogen-containing rings. A correlation between the steroid structure and the product ions obtained has been postulated. The application of these correlations can be useful in the elucidation of feasible structures for unknown steroids and/or their metabolites.

Mass Spectrometric Evaluation of Mephedrone In Vivo Human Metabolism: Identification of Phase I and Phase II Metabolites, Including a Novel Succinyl Conjugate

“…The product ion spectrum showed the two expected losses of water: the one coming from the ketone observed in most of the mephedrone (Pozo et al, 2008). Therefore, 49-hydroxymethyl-mephedrone was proposed for M6 in agreement with previously published studies (Meyer et al, 2010;Khreit et al, 2013;Martínez-Clemente et al, 2013;Pedersen et al, 2013).…”

Detection and Characterization of a New Metabolite of 17α-Methyltestosterone

“…Both analytes showed losses of water and acetone as main ions in the area of m/z close to the precursor ion. This is a common behavior for 17-methylated anabolic steroids (Pozo et al, 2008c) and was supported by accurate mass measurement experiments ( Table 2). …”

“…At 30 eV of collision energy, four abundant ions were obtained (m/z 210, 195, 183, and 169). One of them (m/z 210) is an odd electron ion (OE ϩ ), which is quite unusual in the fragmentation of anabolic steroids (Pozo et al, 2008c). Other OE ϩ such as m/z 268 were also found with lower abundance.…”

“…Regarding the first area, the metabolite A5 exhibited two losses of water (m/z 283 and 265), identical to the number of oxygen atoms present in the molecule, which is common for those 3-oxo-steroids without either a 1,4-diene or a 4,9,11-triene function (Pozo et al, 2008c). In addition, the ion at m/z 225 could be explained by the subsequent losses of H 2 O and acetone, suggesting the presence of a 17-hydroxy-17-methyl moiety in the analyte.…”

“…Afterward, urine was collected every 24 h and stored at Ϫ20°C Once the molecular formula of the metabolites was obtained, their EI spectra in both quadrupole and TOF analyzers were studied and compared with those obtained for methyltestosterone (parent compound). The occurrence of common and related ions was used as an indication for the presence of a part of the structure (Pozo et al, 2008c).…”