Sensitive Gas Chromatography-Mass Spectrometry Method for Simultaneous Measurement of MDEA, MDMA, and Metabolites HMA, MDA, and HMMA in Human Urine

Abstract

A sensitive gas chromatography-mass spectrometry method was developed and validated for the simultaneous measurement of MDEA, MDMA, and its metabolites, 3,4-methylenedioxy-N-ethylamphetamine (MDEA), 3,4-methylenedioxymethamphetamine (MDMA or Ecstasy), and its metabolites, 4-hydroxy-3-methoxyamphetamine (HMA), 3,4-methylenedioxyamphetamine (MDA), and 4-hydroxy-3-methoxyamphetamine (HMMA) in human urine. We hydrolyzed 1 mL urine, fortified with MDMA-d5, MDA-d5, and MDEA-d6, with 100 microL of concentrated hydrochloric acid at 120 degrees C for 40 min, then added 100 microL 10 N sodium hydroxide and 3 mL phosphate buffer 0.1 N (pH 6.0) were added to hydrolyzed urine specimens before solid-phase extraction. After elution and evaporation, we derivatized extracts with heptafluorobutyric acid anhydride and analyzed with gas chromatography-mass spectrometry operated in EI-selected ion-monitoring mode. Limits of quantification were 25 microg/L for MDEA, MDMA, and its metabolites. Calibration curves were linear to 5000 microg/L for MDEA, MDMA, HMA, MDA, and HMMA, with a minimum r2 > 0.99. At 3 concentrations spanning the linear dynamic range of the assay, mean overall extraction efficiencies from urine were >85.5% for all compounds of interest. Intra- and interassay imprecisions, produced as CV, were <15% for all drugs at 30, 300, and 3000 microg/L. This gas chromatography-mass spectrometry assay provides adequate sensitivity and performance characteristics for the simultaneous quantification of MDEA, MDMA, and its metabolites HMMA, MDA, and HMA in human urine. The method meets and exceeds the requirements of the proposed Substance Abuse and Mental Health Services Administration's guidelines for federal workplace drug testing of MDEA and MDMA in urine.