Differentiation of methylenedioxybenzylpiperazines (MDBPs) and methoxymethylbenzylpiperazines (MMBPs) By GC-IRD and GC–MS

2012

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Gas chromatography with infrared detection (GC-IRD) provides direct confirmatory data for the differentiation between the six regioisomeric aromatic ring substituted dimethoxybenzylpiperazines (DMBPs). These regioisomeric substances are resolved by GC and the vapour-phase infrared spectra clearly differentiate among the six dimethoxybenzyl substitution patterns. The mass spectra for these regioisomeric substances are almost identical. With only the 2,3-dimethoxy isomer showing one unique major fragment ion at m/z 136. Thus mass spectrometry does not provide for the confirmation of identity of any one of these compounds to the exclusion of the other isomers. Perfluoroacylation of the secondary amine nitrogen for each of the six regioisomers gave mass spectra showing some differences in the relative abundance of fragment ions without the appearance of any unique fragments for specific confirmation of structure. Gas chromatography coupled with time-of-flight mass spectrometric detection (GC-TOF) provided an additional means of confirmation of the elemental composition of the major fragment ions in the mass spectra of these compounds.

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

GC‐MS and GC‐IRD studies on the six‐ring regioisomeric dimethoxybenzylpiperazines (DMBPs)

2012

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“…Analysis of drugs of abuse in biological and forensic samples has been the focus of many studies over the past years. Gas chromatography‐mass spectrometry (GC‐MS) is the most widely used technique in the analysis of controlled substances in forensic laboratories . A recent report showed that 3,4‐MDBP cannot be differentiated from its 2,3 regioisomer using mass spectrometry even after chemical derivatization.…”

Section: Introductionmentioning

confidence: 99%

Differentiation of methylbenzylpiperazines (MBPs) and benzoylpiperazine (BNZP) using GC‐MS and GC‐IRD

2012

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Three-ring substituted methylbenzylpiperazines (MBPs) and their isobaric benzoylpiperazine (BNZP) have equal mass and many common mass spectral fragment ions. The mass spectrum of BNZP yields a unique benzoyl-group containing fragment at m/z 122 and an additional major fragment at m/z 69 that allows its discrimination from the three MBP regioisomers. Perfluoroacylation of the secondary amine nitrogen of these isomeric piperazines gave mass spectra with differences in relative abundance of some fragment ions but acylation does not alter the fragmentation pathway and did not provide additional MS fragments of discrimination among these isomers. Gas chromatography coupled with infrared detection (GC-IRD) provides direct confirmatory data for the structural differentiation between the four isomers. The mass spectra in combination with the vapour phase IR spectra provide for specific confirmation of each of the isomeric piperazines. The underivatized and perfluoroacyl derivatives of these four piperazines were resolved on a stationary phase of 100% trifluoropropyl methyl polysiloxane (Rtx-200). Gas chromatography coupled with time-of-flight mass spectrometry provides an additional means of differentiating between the isobaric MBP and BNZP which have equivalent nominal masses but are different in their elemental composition and exact masses.

“…GC‐MS is the most commonly employed technique in the analysis of controlled substances in forensic laboratories . The identification of psychoactive drugs in a number of chemical categories is complicated by the existence of regioisomeric and isobaric substances related to the target drug . These isomeric substances are a challenge to forensic analyses that must depend heavily on mass spectrometry for confirmation level data.…”

Section: Introductionmentioning

confidence: 99%

“…[16][17][18][19][20][21] The identification of psychoactive drugs in a number of chemical categories is complicated by the existence of regioisomeric and isobaric substances related to the target drug. [9][10][11][12][13][14][15][16][17] These isomeric substances are a challenge to forensic analyses that must depend heavily on mass spectrometry for confirmation level data. These regioisomeric and isobaric substances have the same nominal mass and yield essentially identical mass spectra.…”

Section: Introductionmentioning

confidence: 99%

Differentiation of methoxybenzoylpiperazines (OMeBzPs) and methylenedioxybenzylpiperazines (MDBPs) By GC‐IRD and GC‐MS

2011

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The designer drug 3,4-methylenedioxybenzylpiperazine (3,4-MDBP), its positional isomer 2,3-methylenedioxybenzylpiperazine (2,3-MDBP) and three regioisomeric ring-substituted methoxybenzoylpiperazines (OMeBzPs) have identical elemental composition and no marked differences in their mass spectra with only the three methoxybenzoylpiperazine regioisomers showing one unique major fragment ion at m/z 152. 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. Exact mass determination using gas chromatography coupled to time-of-flight mass spectrometry (GC-TOF-MS) did not provide any discrimination among these compounds since the main fragment ions are of identical elemental composition. 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 psychoactive designer drug 3,4-MDBP from its direct (2,3-MDBP) and indirect (OMeBzPs) regioisomers. The mass spectra in combination with the vapour phase infrared spectra provide for specific confirmation of each of the isomeric piperazines. The underivatized and perfluoroacyl derivative forms of the five piperazines involved in this study were resolved on a stationary phase of 100% trifluoropropyl methyl polysiloxane (Rtx-200).