Differentiation of the 1-(methylenedioxyphenyl)-2-piperazinopropanes and 1-(methoxyphenyl)-2-piperazinopropanones by GC-IRD and GC-MS

Abstract

Two amphetamine-like piperazine-containing compounds, 1-(3,4-methylenedioxyphenyl)-2-piperazinopropane (3,4-MDPPP), its positional isomer 1-(2,3-methylenedioxyphenyl)-2-piperazinopropane (2,3-MDPPP) and three methcathinone-like piperazine-containing regioisomeric ring substituted 1-(methoxyphenyl)-2-piperazinopropanones (OMePPPOs) have identical elemental composition and no marked differences in their mass spectra. Perfluoroacylation of the secondary amine nitrogen of these isomeric piperazines gave mass spectra with differences in the relative abundance of some fragment ions but did not alter the fragmentation pathway to provide unique ions for discrimination among these isomers. Gas chromatography coupled to infrared detection (GC-IRD) provides direct confirmatory data for the identification of the carbonyl containing compounds and the differentiation of the 3,4-MDPPP from its direct (2,3-MDPPP) and indirect (OMePPPOs) regioisomers. The vapor phase infrared spectra provide for specific confirmation of each of the isomeric piperazines. The perfluoroacyl derivative forms of the five piperazines involved in this study were resolved on two stationary phases, the first is composed of 100% dimethyl polysiloxane (Rtx-1) and the second of 5% diphenyl and 95% dimethyl polysiloxane (Rtx-5).

Keywords: GC-IRD; GC–MS; Methoxyphenylpiperazinopropanones; Methylenedioxyphenylpiperazinopropanes; Perfluoroacylation; Regioisomers.