CORT, CCONE, 11-DECOL, ADIONE, TESTO, 17-OHP and PROG were purchased from Sigma-Aldrich® (St. Louis, MO, USA). 2H3-CORT, 2H8-CCONE, 2H5-11-DECOL, 2H5-ADIONE, 2H5-TESTO, 2H8-17-OHP, 2H9-PROG were from CHSTM MSMS Steroids Kit, PerkinElmer® (Turku, Finland). Water (H2O), methanol (MeOH), acetonitrile (ACN) LC-MS grade were from Romil-Pure chemistry® (Cambridge, UK). Formic acid and ethanol LC-MS grade were from Sigma-Aldrich® (St. Louis, MO, USA). HPLC solvent additive was from CHS MSMS Steroids Tool Box, PerkinElmer® (Turku, Finland).