Simultaneous enantiomeric determination of MDMA and its phase I and phase II metabolites in urine by liquid chromatography-tandem mass spectrometry with chiral derivatization.
A liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MSMS) procedure was developed for the simultaneous determination of enantiomers of the prevalent designer drug 3,4-methylenedioxymethamphetamine (MDMA) and its phase I and phase II metabolites in urine with chiral derivatization. The analytes in urine were directly derivatized with chiral Marfeys reagent, N(α)-(5-fluoro-2,4-dinitrophenyl)-D-leucinamide, without extraction. The diastereomers of the N(α)-(2,4-dinitrophenyl)-D-leucinamide derivatives generated were determined by LC-MSMS. Satisfactory chromatographic separation was achieved for the enantiomers of MDMA and its metabolites 3,4-methylenedioxyamphetamine, 4-hydroxy-3-methoxymethamphetamine (HMMA), HMMA glucuronide, and HMMA sulfate on a semimicro octadecylsilane column using linear gradient elution. With use of multiple reaction monitoring mode, the limits of detection of these analytes ranged from 0.01 to 0.03 μgmL. Linear calibration curves were obtained for all enantiomers from 0.1 to 20 μgmL in urine. The method showed sufficient reproducibility and quantitative ability. This is the first report of a simple LC-MSMS-based analytical procedure with direct chiral derivatization in aqueous media that allows simultaneous enantiomeric determination of drugs and their metabolites, including glucuronide and sulfate derivatives.