title: GC-MS analysis of ring and side chain regioisomers of ethoxyphenethylamines.
abstract: Mass spectral differentiation of 3,4-methylenedioxymethamphetamine (3,4-MDMA), a controlled drug, and its 2,3-regioisomer from the ring substituted ethoxyphenethylamines is possible after formation of the perfluoroacyl derivatives, pentafluoropropionamides (PFPA), and heptafluorobutyrylamides (HFBA). The ring substituted ethoxyphenethylamines constitute a unique set of compounds having an isobaric relationship with 3,4-MDMA. These isomeric forms of the 2-, 3-, and 4-ethoxy phenethylamines have mass spectra essentially equivalent to 3,4-MDMA; all have molecular weight of 193 and major fragment ions in their electron ionization mass spectra at m/z 58 and 135/136. All the side chain regioisomers of 2-ethoxy phenethylamine having equivalent mass spectra to 3,4-MDMA are synthesized and compared via gas chromatography-mass spectrometry to 2,3- and 3,4-methylenedioxymethamphetamine. The mass spectra for the perfluoroacyl derivatives of the primary and secondary amine regioisomers are significantly individualized, and the side chain regioisomers yield unique hydrocarbon fragment ions at m/z 148, 162, and 176. Additionally, the substituted ethoxymethamphetamines are distinguished from the methylenedioxymethamphet-amines via the presence of the m/z 107 ion. Gas chromatographic separation on relatively non-polar stationary phases successfully resolves these derivatives.
authors.affiliation: Department of Pharmacal Sciences, School of Pharmacy, Auburn University, Auburn, AL 36849, USA.
authors.forename: Tamer
authors.initials: T
authors.lastname: Awad
authors.forename: Jack
authors.initials: J
authors.lastname: DeRuiter
authors.forename: C Randall
authors.initials: CR
authors.lastname: Clark
mesh_terms: D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D007202:Indicators and Reagents; D010627:Phenethylamines / Q000032:analysis / Q000737:chemistry*
chemical_list: D007202:Indicators and Reagents; D010627:Phenethylamines