<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="6.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Thevis, M.</style></author><author><style face="normal" font="default" size="100%">Beuck, S.</style></author><author><style face="normal" font="default" size="100%">Hoppner, S.</style></author><author><style face="normal" font="default" size="100%">Thomas, A.</style></author><author><style face="normal" font="default" size="100%">Held, J.</style></author><author><style face="normal" font="default" size="100%">Schafer, M.</style></author><author><style face="normal" font="default" size="100%">Oomens, J.</style></author><author><style face="normal" font="default" size="100%">Schanzer, W.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Structure Elucidation of the Diagnostic Product Ion at m/z 97 Derived from Androst-4-en-3-One-Based Steroids by ESI-CID and IRMPD Spectroscopy</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of the American Society for Mass Spectrometry</style></secondary-title><alt-title><style face="normal" font="default" size="100%">J. Am. Soc. Mass Spectrom.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">ADRENOCORTICAL TUMORS</style></keyword><keyword><style  face="normal" font="default" size="100%">Anabolic steroids</style></keyword><keyword><style  face="normal" font="default" size="100%">CHILDREN</style></keyword><keyword><style  face="normal" font="default" size="100%">CHROMATOGRAPHY</style></keyword><keyword><style  face="normal" font="default" size="100%">COLLISION-INDUCED DISSOCIATION</style></keyword><keyword><style  face="normal" font="default" size="100%">COMPLEXES</style></keyword><keyword><style  face="normal" font="default" size="100%">FRAGMENTATION</style></keyword><keyword><style  face="normal" font="default" size="100%">GAS-PHASE</style></keyword><keyword><style  face="normal" font="default" size="100%">INFRARED-SPECTROSCOPY</style></keyword><keyword><style  face="normal" font="default" size="100%">Mass spectrometry</style></keyword><keyword><style  face="normal" font="default" size="100%">PROFILE ANALYSIS</style></keyword><keyword><style  face="normal" font="default" size="100%">Structure elucidation</style></keyword><keyword><style  face="normal" font="default" size="100%">TANDEM MASS-SPECTROMETRY</style></keyword><keyword><style  face="normal" font="default" size="100%">URINE</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2012</style></year><pub-dates><date><style  face="normal" font="default" size="100%">Mar</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">&lt;Go to ISI&gt;://WOS:000302468800013 </style></url></web-urls></urls><number><style face="normal" font="default" size="100%">3</style></number><volume><style face="normal" font="default" size="100%">23</style></volume><pages><style face="normal" font="default" size="100%">537-546</style></pages><isbn><style face="normal" font="default" size="100%">1044-0305</style></isbn><language><style face="normal" font="default" size="100%">English</style></language><abstract><style face="normal" font="default" size="100%">Structure elucidation of steroids by mass spectrometry has been of great importance to various analytical arenas and numerous studies were conducted to provide evidence for the composition and origin of (tandem) mass spectrometry-derived product ions used to characterize and identify steroidal substances. The common product ion at m/z 97 generated from androst-4-ene-3-one analogs has been subject of various studies, including stable isotope-labeling and (high resolution/high accuracy) tandem mass spectrometry, but its gas-phase structure has never been confirmed. Using high resolution/high accuracy mass spectrometry and low resolution tandem mass spectrometry, density functional theory (DFT) calculation, and infrared multiple photon dissociation (IRMPD) spectroscopy employing a free electron laser, the structure of m/z 97 derived from testosterone was assigned to protonated 3-methyl-2-cyclopenten-1-one. This ion was identified in a set of six cyclic C6HgO+ isomers as computed at the B3LYP/6-311++G(2d,2p) level of theory (protonated 3-methyl-2-cyclopenten-1-one, 2-methyl-2-cyclopenten-1-one and 2-cyclohexen-1-one). Product ions of m/z 97 obtained from MS2 and MS3 experiments of protonated 3-methyl-2-cyclopenten-1-one, 2-methyl-2-cyclopenten-1-one, 2-cyclohexen-1-one, and testosterone corrobo-rated the suggested gas-phase ion structure, which was eventually substantiated by IRMPD spectroscopy yielding a spectrum that convincingly matched the predicted counterpart. Finally, the dissociation pathway of the protonated molecule of testosterone to m/z 97 was revisited and an alternative pathway was suggested that considers the exclusion of C-10 along with the inclusion of C-5, which was experimentally demonstrated with stable isotope labeling.</style></abstract><work-type><style face="normal" font="default" size="100%">Article</style></work-type><accession-num><style face="normal" font="default" size="100%">WOS:000302468800013</style></accession-num><notes><style face="normal" font="default" size="100%">ISI Document Delivery No.: 921HNTimes Cited: 0Cited Reference Count: 34</style></notes><custom1><style face="normal" font="default" size="100%">GUTHz</style></custom1><custom2><style face="normal" font="default" size="100%">Molecular Dynamics</style></custom2><auth-address><style face="normal" font="default" size="100%">[Thevis, Mario; Beuck, Simon; Hoeppner, Sebastian; Thomas, Andreas; Schaenzer, Wilhelm] German Sport Univ Cologne, Ctr Prevent Doping Res, Inst Biochem, D-50933 Cologne, Germany. [Held, Joseph; Schaefer, Mathias] Univ Cologne, Dept Chem, D-50931 Cologne, Germany. [Oomens, Jos] FOM Inst Plasma Phys Rijnhuizen, Nieuwegein, Netherlands. [Oomens, Jos] Univ Amsterdam, Amsterdam, Netherlands.Thevis, M (reprint author), German Sport Univ Cologne, Ctr Prevent Doping Res, Inst Biochem, Sportpk Mungersdorf 6, D-50933 Cologne, Germanym.thevis@biochem.dshs-koeln.de</style></auth-address></record></records></xml>