GC-MS and GC-IRD Studies on Dimethoxyamphetamines (DMA): Regioisomers Related to 2,5-DMA

• NCJ Number: 255298
• Journal: Forensic Science International Volume: 192 Issue: 1-3 Dated: November 2009 Pages: 115-125
• Author(s): Hadir. M. Maher; Tamer Awad; Jack DeRuiter; C. R. Clark
• Date Published: November 2009
• Length: 11 pages
• Grant Number(s): 2006-DN-BX-K016
• Agencies: NIJ-Sponsored
• Publication Type: Research (Applied/Empirical); Report (Study/Research); Report (Grant Sponsored); Program/Project Description
• Award: Synthesis and Analytical Profiles for Regiosomeric and Isobaric Amines Related to MDMA, MDEA and MBDB: Differentiation of Drug and non-Drug Substances of Mass Spectral Equivalence.

Annotation

This article reports on GC-MS and GC-IRD studies on dimethoxyamphetamines (DMA).

Abstract

The mass spectrum of the drug of abuse 2,5-dimethoxyamphetamine (2,5-DMA) is characterized by an imine fragment base peak at m/z 44 and additional fragments at m/z 151/152 for the dimethoxybenzyl cation and radical cation, respectively. Five positional ring isomers of dimethoxyamphetamines (DMA) have an isomeric relationship to 2,5-DMA. All six compounds have the same molecular weight and produce similar EI mass spectra. This lack of mass spectral specificity for the isomers in addition to the possibility of chromatographic coelution could result in misidentification. The lack of reference materials for the potential imposter molecules constitutes a significant analytical challenge. Perfluoroacylation of the amine group reduced the nitrogen basicity and provided individual fragmentation pathways for discrimination between these compounds based on some unique fragment ions and the relative abundance of common ions. GC-IRD studies provided additional structure-IR spectra relationships and yielded confirmation level identification for each of the six regioisomeric dimethoxyamphetamines. The amines and their perfluoroacylated derivatives were resolved by capillary gas chromatography and the amines showed excellent resolution on the more polar stationary phase, Rtx-200. (publisher abstract modified)