This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1002/jms.3973 This article is protected by copyright. All rights reserved. IONIZATION AND COLLISION INDUCED DISSOCIATION OF STEROID BIS-GLUCURONIDES Argitxu Esquivel 1,2 ; Xavier Matabosch 1 ; Aristotelis Kotronoulas 3,4 ; Georgina Balcells 1,2 ; Jesús Joglar 3 ; Rosa Ventura 1,2 * 1. Barcelona Antidoping Laboratory, Doping Control Research Group, IMIM, Hospital del Mar Medical Research Institute, Doctor Aiguader 88, 08003 Barcelona, Spain. 2. Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Doctor Aiguader 88, 08003 Barcelona, Spain. 3. Department of Biological Chemistry and Molecular Modeling, Instituto de Química Avanzada de Cataluña, Consejo Superior de Investigaciones Científicas (IQAC- CSIC), Jordi Girona 18-26, 08034 Barcelona, Spain. 4. Integrative Pharmacology and Systems Neurocience Research Group, IMIM, Hospital del Mar Medical Research Institute, Doctor Aiguader 88, 08003 Barcelona, Spain. *Corresponding author: Rosa Ventura Alemany Barcelona Antidoping Laboratory, Doping Control Research Group IMIM, Hospital del Mar Medical Research Institute Doctor Aiguader 88 08003 Barcelona, Spain Tel. 34933160471 Fax 34933160499 E-mail: rventura@imim.es