Plasma LSD and MDMA concentrations
BLOOD
Plasma concentrations of LSD and MDMA and their metabolites were measured before and 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 5, 6, 7, 8, 9, 10, 11, 12, and 24 h after drug administration. Blood was collected into lithium heparin tubes. The blood samples were immediately centrifuged, and the plasma was subsequently stored at −80°C until analysis. Plasma concentrations of LSD and its metabolite 2-oxo-3-hydroxy-LSD (O-H-LSD) were determined by ultra-high-performance liquid chromatography tandem mass spectrometry with a lower limit of quantification of 10 pg/ml [MDMA and its metabolites 3,4-methylenedioxyamphetamine (MDA) and 4-hydroxy-3-methoxymethamphetamine (HMMA) were analyzed in human plasma using high-performance liquid chromatography tandem mass spectrometry as previously described. HMMA concentration was determined after enzymatic deglucuronidation [